1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Read-Copy Update module-based torture test facility
4 *
5 * Copyright (C) IBM Corporation, 2005, 2006
6 *
7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
8 * Josh Triplett <josh@joshtriplett.org>
9 *
10 * See also: Documentation/RCU/torture.rst
11 */
12
13 #define pr_fmt(fmt) fmt
14
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/kthread.h>
20 #include <linux/err.h>
21 #include <linux/spinlock.h>
22 #include <linux/smp.h>
23 #include <linux/rcupdate_wait.h>
24 #include <linux/rcu_notifier.h>
25 #include <linux/interrupt.h>
26 #include <linux/sched/signal.h>
27 #include <uapi/linux/sched/types.h>
28 #include <linux/atomic.h>
29 #include <linux/bitops.h>
30 #include <linux/completion.h>
31 #include <linux/moduleparam.h>
32 #include <linux/percpu.h>
33 #include <linux/notifier.h>
34 #include <linux/reboot.h>
35 #include <linux/freezer.h>
36 #include <linux/cpu.h>
37 #include <linux/delay.h>
38 #include <linux/stat.h>
39 #include <linux/srcu.h>
40 #include <linux/slab.h>
41 #include <linux/trace_clock.h>
42 #include <asm/byteorder.h>
43 #include <linux/torture.h>
44 #include <linux/vmalloc.h>
45 #include <linux/sched/debug.h>
46 #include <linux/sched/sysctl.h>
47 #include <linux/oom.h>
48 #include <linux/tick.h>
49 #include <linux/rcupdate_trace.h>
50 #include <linux/nmi.h>
51
52 #include "rcu.h"
53
54 MODULE_DESCRIPTION("Read-Copy Update module-based torture test facility");
55 MODULE_LICENSE("GPL");
56 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@joshtriplett.org>");
57
58 // Bits for ->extendables field, extendables param, and related definitions.
59 #define RCUTORTURE_RDR_SHIFT_1 8 // Put SRCU index in upper bits.
60 #define RCUTORTURE_RDR_MASK_1 (0xff << RCUTORTURE_RDR_SHIFT_1)
61 #define RCUTORTURE_RDR_SHIFT_2 16 // Put SRCU index in upper bits.
62 #define RCUTORTURE_RDR_MASK_2 (0xff << RCUTORTURE_RDR_SHIFT_2)
63 #define RCUTORTURE_RDR_BH 0x01 // Extend readers by disabling bh.
64 #define RCUTORTURE_RDR_IRQ 0x02 // ... disabling interrupts.
65 #define RCUTORTURE_RDR_PREEMPT 0x04 // ... disabling preemption.
66 #define RCUTORTURE_RDR_RBH 0x08 // ... rcu_read_lock_bh().
67 #define RCUTORTURE_RDR_SCHED 0x10 // ... rcu_read_lock_sched().
68 #define RCUTORTURE_RDR_RCU_1 0x20 // ... entering another RCU reader.
69 #define RCUTORTURE_RDR_RCU_2 0x40 // ... entering another RCU reader.
70 #define RCUTORTURE_RDR_UPDOWN 0x80 // ... up-read from task, down-read from timer.
71 // Note: Manual start, automatic end.
72 #define RCUTORTURE_RDR_NBITS 8 // Number of bits defined above.
73 #define RCUTORTURE_MAX_EXTEND \
74 (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
75 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED) // Intentionally omit RCUTORTURE_RDR_UPDOWN.
76 #define RCUTORTURE_RDR_ALLBITS \
77 (RCUTORTURE_MAX_EXTEND | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2 | \
78 RCUTORTURE_RDR_MASK_1 | RCUTORTURE_RDR_MASK_2)
79 #define RCUTORTURE_RDR_MAX_LOOPS 0x7 /* Maximum reader extensions. */
80 /* Must be power of two minus one. */
81 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
82
83 torture_param(int, extendables, RCUTORTURE_MAX_EXTEND,
84 "Extend readers by disabling bh (1), irqs (2), or preempt (4)");
85 torture_param(int, fqs_duration, 0, "Duration of fqs bursts (us), 0 to disable");
86 torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
87 torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
88 torture_param(int, fwd_progress, 1, "Number of grace-period forward progress tasks (0 to disable)");
89 torture_param(int, fwd_progress_div, 4, "Fraction of CPU stall to wait");
90 torture_param(int, fwd_progress_holdoff, 60, "Time between forward-progress tests (s)");
91 torture_param(bool, fwd_progress_need_resched, 1, "Hide cond_resched() behind need_resched()");
92 torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
93 torture_param(bool, gp_cond_exp, false, "Use conditional/async expedited GP wait primitives");
94 torture_param(bool, gp_cond_full, false, "Use conditional/async full-state GP wait primitives");
95 torture_param(bool, gp_cond_exp_full, false,
96 "Use conditional/async full-stateexpedited GP wait primitives");
97 torture_param(int, gp_cond_wi, 16 * USEC_PER_SEC / HZ,
98 "Wait interval for normal conditional grace periods, us (default 16 jiffies)");
99 torture_param(int, gp_cond_wi_exp, 128,
100 "Wait interval for expedited conditional grace periods, us (default 128 us)");
101 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
102 torture_param(bool, gp_normal, false, "Use normal (non-expedited) GP wait primitives");
103 torture_param(bool, gp_poll, false, "Use polling GP wait primitives");
104 torture_param(bool, gp_poll_exp, false, "Use polling expedited GP wait primitives");
105 torture_param(bool, gp_poll_full, false, "Use polling full-state GP wait primitives");
106 torture_param(bool, gp_poll_exp_full, false, "Use polling full-state expedited GP wait primitives");
107 torture_param(int, gp_poll_wi, 16 * USEC_PER_SEC / HZ,
108 "Wait interval for normal polled grace periods, us (default 16 jiffies)");
109 torture_param(int, gp_poll_wi_exp, 128,
110 "Wait interval for expedited polled grace periods, us (default 128 us)");
111 torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
112 torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
113 torture_param(int, leakpointer, 0, "Leak pointer dereferences from readers");
114 torture_param(int, n_barrier_cbs, 0, "# of callbacks/kthreads for barrier testing");
115 torture_param(int, n_up_down, 32, "# of concurrent up/down hrtimer-based RCU readers");
116 torture_param(int, nfakewriters, 4, "Number of RCU fake writer threads");
117 torture_param(int, nreaders, -1, "Number of RCU reader threads");
118 torture_param(int, object_debug, 0, "Enable debug-object double call_rcu() testing");
119 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
120 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (jiffies), 0=disable");
121 torture_param(bool, gpwrap_lag, true, "Enable grace-period wrap lag testing");
122 torture_param(int, gpwrap_lag_gps, 8, "Value to set for set_gpwrap_lag during an active testing period.");
123 torture_param(int, gpwrap_lag_cycle_mins, 30, "Total cycle duration for gpwrap lag testing (in minutes)");
124 torture_param(int, gpwrap_lag_active_mins, 5, "Duration for which gpwrap lag is active within each cycle (in minutes)");
125 torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disable");
126 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
127 torture_param(int, preempt_duration, 0, "Preemption duration (ms), zero to disable");
128 torture_param(int, preempt_interval, MSEC_PER_SEC, "Interval between preemptions (ms)");
129 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
130 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
131 torture_param(int, reader_flavor, SRCU_READ_FLAVOR_NORMAL, "Reader flavors to use, one per bit.");
132 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
133 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
134 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
135 torture_param(int, stall_cpu_holdoff, 10, "Time to wait before starting stall (s).");
136 torture_param(bool, stall_no_softlockup, false, "Avoid softlockup warning during cpu stall.");
137 torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
138 torture_param(int, stall_cpu_block, 0, "Sleep while stalling.");
139 torture_param(int, stall_cpu_repeat, 0, "Number of additional stalls after the first one.");
140 torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s).");
141 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s");
142 torture_param(int, stutter, 5, "Number of seconds to run/halt test");
143 torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
144 torture_param(int, test_boost_duration, 4, "Duration of each boost test, seconds.");
145 torture_param(int, test_boost_holdoff, 0, "Holdoff time from rcutorture start, seconds.");
146 torture_param(int, test_boost_interval, 7, "Interval between boost tests, seconds.");
147 torture_param(int, test_nmis, 0, "End-test NMI tests, 0 to disable.");
148 torture_param(bool, test_no_idle_hz, true, "Test support for tickless idle CPUs");
149 torture_param(int, test_srcu_lockdep, 0, "Test specified SRCU deadlock scenario.");
150 torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
151
152 static char *torture_type = "rcu";
153 module_param(torture_type, charp, 0444);
154 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, srcu, ...)");
155
156 static int nrealnocbers;
157 static int nrealreaders;
158 static int nrealfakewriters;
159 static struct task_struct *writer_task;
160 static struct task_struct **fakewriter_tasks;
161 static struct task_struct **reader_tasks;
162 static struct task_struct *updown_task;
163 static struct task_struct **nocb_tasks;
164 static struct task_struct *stats_task;
165 static struct task_struct *fqs_task;
166 static struct task_struct *boost_tasks[NR_CPUS];
167 static struct task_struct *stall_task;
168 static struct task_struct **fwd_prog_tasks;
169 static struct task_struct **barrier_cbs_tasks;
170 static struct task_struct *barrier_task;
171 static struct task_struct *read_exit_task;
172 static struct task_struct *preempt_task;
173
174 #define RCU_TORTURE_PIPE_LEN 10
175
176 // Mailbox-like structure to check RCU global memory ordering.
177 struct rcu_torture_reader_check {
178 unsigned long rtc_myloops;
179 int rtc_chkrdr;
180 unsigned long rtc_chkloops;
181 int rtc_ready;
182 struct rcu_torture_reader_check *rtc_assigner;
183 } ____cacheline_internodealigned_in_smp;
184
185 // Update-side data structure used to check RCU readers.
186 struct rcu_torture {
187 struct rcu_head rtort_rcu;
188 int rtort_pipe_count;
189 struct list_head rtort_free;
190 int rtort_mbtest;
191 struct rcu_torture_reader_check *rtort_chkp;
192 };
193
194 static LIST_HEAD(rcu_torture_freelist);
195 static struct rcu_torture __rcu *rcu_torture_current;
196 static unsigned long rcu_torture_current_version;
197 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
198 static DEFINE_SPINLOCK(rcu_torture_lock);
199 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count);
200 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch);
201 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
202 static struct rcu_torture_reader_check *rcu_torture_reader_mbchk;
203 static atomic_t n_rcu_torture_alloc;
204 static atomic_t n_rcu_torture_alloc_fail;
205 static atomic_t n_rcu_torture_free;
206 static atomic_t n_rcu_torture_mberror;
207 static atomic_t n_rcu_torture_mbchk_fail;
208 static atomic_t n_rcu_torture_mbchk_tries;
209 static atomic_t n_rcu_torture_error;
210 static long n_rcu_torture_barrier_error;
211 static long n_rcu_torture_boost_ktrerror;
212 static long n_rcu_torture_boost_failure;
213 static long n_rcu_torture_boosts;
214 static atomic_long_t n_rcu_torture_timers;
215 static long n_barrier_attempts;
216 static long n_barrier_successes; /* did rcu_barrier test succeed? */
217 static unsigned long n_read_exits;
218 static struct list_head rcu_torture_removed;
219 static unsigned long shutdown_jiffies;
220 static unsigned long start_gp_seq;
221 static atomic_long_t n_nocb_offload;
222 static atomic_long_t n_nocb_deoffload;
223
224 static int rcu_torture_writer_state;
225 #define RTWS_FIXED_DELAY 0
226 #define RTWS_DELAY 1
227 #define RTWS_REPLACE 2
228 #define RTWS_DEF_FREE 3
229 #define RTWS_EXP_SYNC 4
230 #define RTWS_COND_GET 5
231 #define RTWS_COND_GET_FULL 6
232 #define RTWS_COND_GET_EXP 7
233 #define RTWS_COND_GET_EXP_FULL 8
234 #define RTWS_COND_SYNC 9
235 #define RTWS_COND_SYNC_FULL 10
236 #define RTWS_COND_SYNC_EXP 11
237 #define RTWS_COND_SYNC_EXP_FULL 12
238 #define RTWS_POLL_GET 13
239 #define RTWS_POLL_GET_FULL 14
240 #define RTWS_POLL_GET_EXP 15
241 #define RTWS_POLL_GET_EXP_FULL 16
242 #define RTWS_POLL_WAIT 17
243 #define RTWS_POLL_WAIT_FULL 18
244 #define RTWS_POLL_WAIT_EXP 19
245 #define RTWS_POLL_WAIT_EXP_FULL 20
246 #define RTWS_SYNC 21
247 #define RTWS_STUTTER 22
248 #define RTWS_STOPPING 23
249 static const char * const rcu_torture_writer_state_names[] = {
250 "RTWS_FIXED_DELAY",
251 "RTWS_DELAY",
252 "RTWS_REPLACE",
253 "RTWS_DEF_FREE",
254 "RTWS_EXP_SYNC",
255 "RTWS_COND_GET",
256 "RTWS_COND_GET_FULL",
257 "RTWS_COND_GET_EXP",
258 "RTWS_COND_GET_EXP_FULL",
259 "RTWS_COND_SYNC",
260 "RTWS_COND_SYNC_FULL",
261 "RTWS_COND_SYNC_EXP",
262 "RTWS_COND_SYNC_EXP_FULL",
263 "RTWS_POLL_GET",
264 "RTWS_POLL_GET_FULL",
265 "RTWS_POLL_GET_EXP",
266 "RTWS_POLL_GET_EXP_FULL",
267 "RTWS_POLL_WAIT",
268 "RTWS_POLL_WAIT_FULL",
269 "RTWS_POLL_WAIT_EXP",
270 "RTWS_POLL_WAIT_EXP_FULL",
271 "RTWS_SYNC",
272 "RTWS_STUTTER",
273 "RTWS_STOPPING",
274 };
275
276 /* Record reader segment types and duration for first failing read. */
277 struct rt_read_seg {
278 int rt_readstate;
279 unsigned long rt_delay_jiffies;
280 unsigned long rt_delay_ms;
281 unsigned long rt_delay_us;
282 bool rt_preempted;
283 int rt_cpu;
284 int rt_end_cpu;
285 unsigned long long rt_gp_seq;
286 unsigned long long rt_gp_seq_end;
287 u64 rt_ts;
288 };
289 static int err_segs_recorded;
290 static struct rt_read_seg err_segs[RCUTORTURE_RDR_MAX_SEGS];
291 static int rt_read_nsegs;
292 static int rt_read_preempted;
293
rcu_torture_writer_state_getname(void)294 static const char *rcu_torture_writer_state_getname(void)
295 {
296 unsigned int i = READ_ONCE(rcu_torture_writer_state);
297
298 if (i >= ARRAY_SIZE(rcu_torture_writer_state_names))
299 return "???";
300 return rcu_torture_writer_state_names[i];
301 }
302
303 #ifdef CONFIG_RCU_TRACE
rcu_trace_clock_local(void)304 static u64 notrace rcu_trace_clock_local(void)
305 {
306 u64 ts = trace_clock_local();
307
308 (void)do_div(ts, NSEC_PER_USEC);
309 return ts;
310 }
311 #else /* #ifdef CONFIG_RCU_TRACE */
rcu_trace_clock_local(void)312 static u64 notrace rcu_trace_clock_local(void)
313 {
314 return 0ULL;
315 }
316 #endif /* #else #ifdef CONFIG_RCU_TRACE */
317
318 /*
319 * Stop aggressive CPU-hog tests a bit before the end of the test in order
320 * to avoid interfering with test shutdown.
321 */
shutdown_time_arrived(void)322 static bool shutdown_time_arrived(void)
323 {
324 return shutdown_secs && time_after(jiffies, shutdown_jiffies - 30 * HZ);
325 }
326
327 static unsigned long boost_starttime; /* jiffies of next boost test start. */
328 static DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
329 /* and boost task create/destroy. */
330 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
331 static bool barrier_phase; /* Test phase. */
332 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
333 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
334 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
335
336 static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
337
338 /*
339 * Allocate an element from the rcu_tortures pool.
340 */
341 static struct rcu_torture *
rcu_torture_alloc(void)342 rcu_torture_alloc(void)
343 {
344 struct list_head *p;
345
346 spin_lock_bh(&rcu_torture_lock);
347 if (list_empty(&rcu_torture_freelist)) {
348 atomic_inc(&n_rcu_torture_alloc_fail);
349 spin_unlock_bh(&rcu_torture_lock);
350 return NULL;
351 }
352 atomic_inc(&n_rcu_torture_alloc);
353 p = rcu_torture_freelist.next;
354 list_del_init(p);
355 spin_unlock_bh(&rcu_torture_lock);
356 return container_of(p, struct rcu_torture, rtort_free);
357 }
358
359 /*
360 * Free an element to the rcu_tortures pool.
361 */
362 static void
rcu_torture_free(struct rcu_torture * p)363 rcu_torture_free(struct rcu_torture *p)
364 {
365 atomic_inc(&n_rcu_torture_free);
366 spin_lock_bh(&rcu_torture_lock);
367 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
368 spin_unlock_bh(&rcu_torture_lock);
369 }
370
371 /*
372 * Operations vector for selecting different types of tests.
373 */
374
375 struct rcu_torture_ops {
376 int ttype;
377 void (*init)(void);
378 void (*cleanup)(void);
379 int (*readlock)(void);
380 void (*read_delay)(struct torture_random_state *rrsp,
381 struct rt_read_seg *rtrsp);
382 void (*readunlock)(int idx);
383 int (*readlock_held)(void); // lockdep.
384 int (*readlock_nesting)(void); // actual nesting, if available, -1 if not.
385 int (*down_read)(void);
386 void (*up_read)(int idx);
387 unsigned long (*get_gp_seq)(void);
388 unsigned long (*gp_diff)(unsigned long new, unsigned long old);
389 void (*deferred_free)(struct rcu_torture *p);
390 void (*sync)(void);
391 void (*exp_sync)(void);
392 unsigned long (*get_gp_state_exp)(void);
393 unsigned long (*start_gp_poll_exp)(void);
394 void (*start_gp_poll_exp_full)(struct rcu_gp_oldstate *rgosp);
395 bool (*poll_gp_state_exp)(unsigned long oldstate);
396 void (*cond_sync_exp)(unsigned long oldstate);
397 void (*cond_sync_exp_full)(struct rcu_gp_oldstate *rgosp);
398 unsigned long (*get_comp_state)(void);
399 void (*get_comp_state_full)(struct rcu_gp_oldstate *rgosp);
400 bool (*same_gp_state)(unsigned long oldstate1, unsigned long oldstate2);
401 bool (*same_gp_state_full)(struct rcu_gp_oldstate *rgosp1, struct rcu_gp_oldstate *rgosp2);
402 unsigned long (*get_gp_state)(void);
403 void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp);
404 unsigned long (*start_gp_poll)(void);
405 void (*start_gp_poll_full)(struct rcu_gp_oldstate *rgosp);
406 bool (*poll_gp_state)(unsigned long oldstate);
407 bool (*poll_gp_state_full)(struct rcu_gp_oldstate *rgosp);
408 bool (*poll_need_2gp)(bool poll, bool poll_full);
409 void (*cond_sync)(unsigned long oldstate);
410 void (*cond_sync_full)(struct rcu_gp_oldstate *rgosp);
411 int poll_active;
412 int poll_active_full;
413 call_rcu_func_t call;
414 void (*cb_barrier)(void);
415 void (*fqs)(void);
416 void (*stats)(void);
417 void (*gp_kthread_dbg)(void);
418 bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
419 int (*stall_dur)(void);
420 void (*get_gp_data)(int *flags, unsigned long *gp_seq);
421 void (*gp_slow_register)(atomic_t *rgssp);
422 void (*gp_slow_unregister)(atomic_t *rgssp);
423 bool (*reader_blocked)(void);
424 unsigned long long (*gather_gp_seqs)(void);
425 void (*format_gp_seqs)(unsigned long long seqs, char *cp, size_t len);
426 void (*set_gpwrap_lag)(unsigned long lag);
427 int (*get_gpwrap_count)(int cpu);
428 long cbflood_max;
429 int irq_capable;
430 int can_boost;
431 int extendables;
432 int slow_gps;
433 int no_pi_lock;
434 int debug_objects;
435 int start_poll_irqsoff;
436 int have_up_down;
437 const char *name;
438 };
439
440 static struct rcu_torture_ops *cur_ops;
441
442 /*
443 * Definitions for rcu torture testing.
444 */
445
torture_readlock_not_held(void)446 static int torture_readlock_not_held(void)
447 {
448 return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
449 }
450
rcu_torture_read_lock(void)451 static int rcu_torture_read_lock(void)
452 {
453 rcu_read_lock();
454 return 0;
455 }
456
457 static void
rcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)458 rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
459 {
460 unsigned long started;
461 unsigned long completed;
462 const unsigned long shortdelay_us = 200;
463 unsigned long longdelay_ms = 300;
464 unsigned long long ts;
465
466 /* We want a short delay sometimes to make a reader delay the grace
467 * period, and we want a long delay occasionally to trigger
468 * force_quiescent_state. */
469
470 if (!atomic_read(&rcu_fwd_cb_nodelay) &&
471 !(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
472 started = cur_ops->get_gp_seq();
473 ts = rcu_trace_clock_local();
474 if ((preempt_count() & HARDIRQ_MASK) || softirq_count())
475 longdelay_ms = 5; /* Avoid triggering BH limits. */
476 mdelay(longdelay_ms);
477 rtrsp->rt_delay_ms = longdelay_ms;
478 completed = cur_ops->get_gp_seq();
479 do_trace_rcu_torture_read(cur_ops->name, NULL, ts,
480 started, completed);
481 }
482 if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us))) {
483 udelay(shortdelay_us);
484 rtrsp->rt_delay_us = shortdelay_us;
485 }
486 if (!preempt_count() &&
487 !(torture_random(rrsp) % (nrealreaders * 500)))
488 torture_preempt_schedule(); /* QS only if preemptible. */
489 }
490
rcu_torture_read_unlock(int idx)491 static void rcu_torture_read_unlock(int idx)
492 {
493 rcu_read_unlock();
494 }
495
rcu_torture_readlock_nesting(void)496 static int rcu_torture_readlock_nesting(void)
497 {
498 if (IS_ENABLED(CONFIG_PREEMPT_RCU))
499 return rcu_preempt_depth();
500 if (IS_ENABLED(CONFIG_PREEMPT_COUNT))
501 return (preempt_count() & PREEMPT_MASK);
502 return -1;
503 }
504
505 /*
506 * Update callback in the pipe. This should be invoked after a grace period.
507 */
508 static bool
rcu_torture_pipe_update_one(struct rcu_torture * rp)509 rcu_torture_pipe_update_one(struct rcu_torture *rp)
510 {
511 int i;
512 struct rcu_torture_reader_check *rtrcp = READ_ONCE(rp->rtort_chkp);
513
514 if (rtrcp) {
515 WRITE_ONCE(rp->rtort_chkp, NULL);
516 smp_store_release(&rtrcp->rtc_ready, 1); // Pair with smp_load_acquire().
517 }
518 i = rp->rtort_pipe_count;
519 if (i > RCU_TORTURE_PIPE_LEN)
520 i = RCU_TORTURE_PIPE_LEN;
521 atomic_inc(&rcu_torture_wcount[i]);
522 WRITE_ONCE(rp->rtort_pipe_count, i + 1);
523 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
524 if (i + 1 >= RCU_TORTURE_PIPE_LEN) {
525 rp->rtort_mbtest = 0;
526 return true;
527 }
528 return false;
529 }
530
531 /*
532 * Update all callbacks in the pipe. Suitable for synchronous grace-period
533 * primitives.
534 */
535 static void
rcu_torture_pipe_update(struct rcu_torture * old_rp)536 rcu_torture_pipe_update(struct rcu_torture *old_rp)
537 {
538 struct rcu_torture *rp;
539 struct rcu_torture *rp1;
540
541 if (old_rp)
542 list_add(&old_rp->rtort_free, &rcu_torture_removed);
543 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
544 if (rcu_torture_pipe_update_one(rp)) {
545 list_del(&rp->rtort_free);
546 rcu_torture_free(rp);
547 }
548 }
549 }
550
551 static void
rcu_torture_cb(struct rcu_head * p)552 rcu_torture_cb(struct rcu_head *p)
553 {
554 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
555
556 if (torture_must_stop_irq()) {
557 /* Test is ending, just drop callbacks on the floor. */
558 /* The next initialization will pick up the pieces. */
559 return;
560 }
561 if (rcu_torture_pipe_update_one(rp))
562 rcu_torture_free(rp);
563 else
564 cur_ops->deferred_free(rp);
565 }
566
rcu_no_completed(void)567 static unsigned long rcu_no_completed(void)
568 {
569 return 0;
570 }
571
rcu_torture_deferred_free(struct rcu_torture * p)572 static void rcu_torture_deferred_free(struct rcu_torture *p)
573 {
574 call_rcu_hurry(&p->rtort_rcu, rcu_torture_cb);
575 }
576
rcu_sync_torture_init(void)577 static void rcu_sync_torture_init(void)
578 {
579 INIT_LIST_HEAD(&rcu_torture_removed);
580 }
581
rcu_poll_need_2gp(bool poll,bool poll_full)582 static bool rcu_poll_need_2gp(bool poll, bool poll_full)
583 {
584 return poll;
585 }
586
587 static struct rcu_torture_ops rcu_ops = {
588 .ttype = RCU_FLAVOR,
589 .init = rcu_sync_torture_init,
590 .readlock = rcu_torture_read_lock,
591 .read_delay = rcu_read_delay,
592 .readunlock = rcu_torture_read_unlock,
593 .readlock_held = torture_readlock_not_held,
594 .readlock_nesting = rcu_torture_readlock_nesting,
595 .get_gp_seq = rcu_get_gp_seq,
596 .gp_diff = rcu_seq_diff,
597 .deferred_free = rcu_torture_deferred_free,
598 .sync = synchronize_rcu,
599 .exp_sync = synchronize_rcu_expedited,
600 .same_gp_state = same_state_synchronize_rcu,
601 .same_gp_state_full = same_state_synchronize_rcu_full,
602 .get_comp_state = get_completed_synchronize_rcu,
603 .get_comp_state_full = get_completed_synchronize_rcu_full,
604 .get_gp_state = get_state_synchronize_rcu,
605 .get_gp_state_full = get_state_synchronize_rcu_full,
606 .start_gp_poll = start_poll_synchronize_rcu,
607 .start_gp_poll_full = start_poll_synchronize_rcu_full,
608 .poll_gp_state = poll_state_synchronize_rcu,
609 .poll_gp_state_full = poll_state_synchronize_rcu_full,
610 .poll_need_2gp = rcu_poll_need_2gp,
611 .cond_sync = cond_synchronize_rcu,
612 .cond_sync_full = cond_synchronize_rcu_full,
613 .poll_active = NUM_ACTIVE_RCU_POLL_OLDSTATE,
614 .poll_active_full = NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE,
615 .get_gp_state_exp = get_state_synchronize_rcu,
616 .start_gp_poll_exp = start_poll_synchronize_rcu_expedited,
617 .start_gp_poll_exp_full = start_poll_synchronize_rcu_expedited_full,
618 .poll_gp_state_exp = poll_state_synchronize_rcu,
619 .cond_sync_exp = cond_synchronize_rcu_expedited,
620 .cond_sync_exp_full = cond_synchronize_rcu_expedited_full,
621 .call = call_rcu_hurry,
622 .cb_barrier = rcu_barrier,
623 .fqs = rcu_force_quiescent_state,
624 .gp_kthread_dbg = show_rcu_gp_kthreads,
625 .check_boost_failed = rcu_check_boost_fail,
626 .stall_dur = rcu_jiffies_till_stall_check,
627 .get_gp_data = rcutorture_get_gp_data,
628 .gp_slow_register = rcu_gp_slow_register,
629 .gp_slow_unregister = rcu_gp_slow_unregister,
630 .reader_blocked = IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)
631 ? has_rcu_reader_blocked
632 : NULL,
633 .gather_gp_seqs = rcutorture_gather_gp_seqs,
634 .format_gp_seqs = rcutorture_format_gp_seqs,
635 .set_gpwrap_lag = rcu_set_gpwrap_lag,
636 .get_gpwrap_count = rcu_get_gpwrap_count,
637 .irq_capable = 1,
638 .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
639 .extendables = RCUTORTURE_MAX_EXTEND,
640 .debug_objects = 1,
641 .start_poll_irqsoff = 1,
642 .name = "rcu"
643 };
644
645 /*
646 * Don't even think about trying any of these in real life!!!
647 * The names includes "busted", and they really means it!
648 * The only purpose of these functions is to provide a buggy RCU
649 * implementation to make sure that rcutorture correctly emits
650 * buggy-RCU error messages.
651 */
rcu_busted_torture_deferred_free(struct rcu_torture * p)652 static void rcu_busted_torture_deferred_free(struct rcu_torture *p)
653 {
654 /* This is a deliberate bug for testing purposes only! */
655 rcu_torture_cb(&p->rtort_rcu);
656 }
657
synchronize_rcu_busted(void)658 static void synchronize_rcu_busted(void)
659 {
660 /* This is a deliberate bug for testing purposes only! */
661 }
662
663 static void
call_rcu_busted(struct rcu_head * head,rcu_callback_t func)664 call_rcu_busted(struct rcu_head *head, rcu_callback_t func)
665 {
666 /* This is a deliberate bug for testing purposes only! */
667 func(head);
668 }
669
670 static struct rcu_torture_ops rcu_busted_ops = {
671 .ttype = INVALID_RCU_FLAVOR,
672 .init = rcu_sync_torture_init,
673 .readlock = rcu_torture_read_lock,
674 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
675 .readunlock = rcu_torture_read_unlock,
676 .readlock_held = torture_readlock_not_held,
677 .get_gp_seq = rcu_no_completed,
678 .deferred_free = rcu_busted_torture_deferred_free,
679 .sync = synchronize_rcu_busted,
680 .exp_sync = synchronize_rcu_busted,
681 .call = call_rcu_busted,
682 .gather_gp_seqs = rcutorture_gather_gp_seqs,
683 .format_gp_seqs = rcutorture_format_gp_seqs,
684 .irq_capable = 1,
685 .extendables = RCUTORTURE_MAX_EXTEND,
686 .name = "busted"
687 };
688
689 /*
690 * Definitions for srcu torture testing.
691 */
692
693 DEFINE_STATIC_SRCU(srcu_ctl);
694 static struct srcu_struct srcu_ctld;
695 static struct srcu_struct *srcu_ctlp = &srcu_ctl;
696 static struct rcu_torture_ops srcud_ops;
697
srcu_get_gp_data(int * flags,unsigned long * gp_seq)698 static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
699 {
700 srcutorture_get_gp_data(srcu_ctlp, flags, gp_seq);
701 }
702
srcu_torture_read_lock(void)703 static int srcu_torture_read_lock(void)
704 {
705 int idx;
706 struct srcu_ctr __percpu *scp;
707 int ret = 0;
708
709 WARN_ON_ONCE(reader_flavor & ~SRCU_READ_FLAVOR_ALL);
710
711 if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor & SRCU_READ_FLAVOR_ALL)) {
712 idx = srcu_read_lock(srcu_ctlp);
713 WARN_ON_ONCE(idx & ~0x1);
714 ret += idx;
715 }
716 if (reader_flavor & SRCU_READ_FLAVOR_NMI) {
717 idx = srcu_read_lock_nmisafe(srcu_ctlp);
718 WARN_ON_ONCE(idx & ~0x1);
719 ret += idx << 1;
720 }
721 if (reader_flavor & SRCU_READ_FLAVOR_FAST) {
722 scp = srcu_read_lock_fast(srcu_ctlp);
723 idx = __srcu_ptr_to_ctr(srcu_ctlp, scp);
724 WARN_ON_ONCE(idx & ~0x1);
725 ret += idx << 3;
726 }
727 return ret;
728 }
729
730 static void
srcu_read_delay(struct torture_random_state * rrsp,struct rt_read_seg * rtrsp)731 srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
732 {
733 long delay;
734 const long uspertick = 1000000 / HZ;
735 const long longdelay = 10;
736
737 /* We want there to be long-running readers, but not all the time. */
738
739 delay = torture_random(rrsp) %
740 (nrealreaders * 2 * longdelay * uspertick);
741 if (!delay && in_task()) {
742 schedule_timeout_interruptible(longdelay);
743 rtrsp->rt_delay_jiffies = longdelay;
744 } else {
745 rcu_read_delay(rrsp, rtrsp);
746 }
747 }
748
srcu_torture_read_unlock(int idx)749 static void srcu_torture_read_unlock(int idx)
750 {
751 WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
752 if (reader_flavor & SRCU_READ_FLAVOR_FAST)
753 srcu_read_unlock_fast(srcu_ctlp, __srcu_ctr_to_ptr(srcu_ctlp, (idx & 0x8) >> 3));
754 if (reader_flavor & SRCU_READ_FLAVOR_NMI)
755 srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1);
756 if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor & SRCU_READ_FLAVOR_ALL))
757 srcu_read_unlock(srcu_ctlp, idx & 0x1);
758 }
759
torture_srcu_read_lock_held(void)760 static int torture_srcu_read_lock_held(void)
761 {
762 return srcu_read_lock_held(srcu_ctlp);
763 }
764
srcu_torture_have_up_down(void)765 static bool srcu_torture_have_up_down(void)
766 {
767 int rf = reader_flavor;
768
769 if (!rf)
770 rf = SRCU_READ_FLAVOR_NORMAL;
771 return !!(cur_ops->have_up_down & rf);
772 }
773
srcu_torture_down_read(void)774 static int srcu_torture_down_read(void)
775 {
776 int idx;
777 struct srcu_ctr __percpu *scp;
778
779 WARN_ON_ONCE(reader_flavor & ~SRCU_READ_FLAVOR_ALL);
780 WARN_ON_ONCE(reader_flavor & (reader_flavor - 1));
781
782 if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) || !(reader_flavor & SRCU_READ_FLAVOR_ALL)) {
783 idx = srcu_down_read(srcu_ctlp);
784 WARN_ON_ONCE(idx & ~0x1);
785 return idx;
786 }
787 if (reader_flavor & SRCU_READ_FLAVOR_FAST) {
788 scp = srcu_down_read_fast(srcu_ctlp);
789 idx = __srcu_ptr_to_ctr(srcu_ctlp, scp);
790 WARN_ON_ONCE(idx & ~0x1);
791 return idx << 3;
792 }
793 WARN_ON_ONCE(1);
794 return 0;
795 }
796
srcu_torture_up_read(int idx)797 static void srcu_torture_up_read(int idx)
798 {
799 WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
800 if (reader_flavor & SRCU_READ_FLAVOR_FAST)
801 srcu_up_read_fast(srcu_ctlp, __srcu_ctr_to_ptr(srcu_ctlp, (idx & 0x8) >> 3));
802 else if ((reader_flavor & SRCU_READ_FLAVOR_NORMAL) ||
803 !(reader_flavor & SRCU_READ_FLAVOR_ALL))
804 srcu_up_read(srcu_ctlp, idx & 0x1);
805 else
806 WARN_ON_ONCE(1);
807 }
808
srcu_torture_completed(void)809 static unsigned long srcu_torture_completed(void)
810 {
811 return srcu_batches_completed(srcu_ctlp);
812 }
813
srcu_torture_deferred_free(struct rcu_torture * rp)814 static void srcu_torture_deferred_free(struct rcu_torture *rp)
815 {
816 call_srcu(srcu_ctlp, &rp->rtort_rcu, rcu_torture_cb);
817 }
818
srcu_torture_synchronize(void)819 static void srcu_torture_synchronize(void)
820 {
821 synchronize_srcu(srcu_ctlp);
822 }
823
srcu_torture_get_gp_state(void)824 static unsigned long srcu_torture_get_gp_state(void)
825 {
826 return get_state_synchronize_srcu(srcu_ctlp);
827 }
828
srcu_torture_start_gp_poll(void)829 static unsigned long srcu_torture_start_gp_poll(void)
830 {
831 return start_poll_synchronize_srcu(srcu_ctlp);
832 }
833
srcu_torture_poll_gp_state(unsigned long oldstate)834 static bool srcu_torture_poll_gp_state(unsigned long oldstate)
835 {
836 return poll_state_synchronize_srcu(srcu_ctlp, oldstate);
837 }
838
srcu_torture_call(struct rcu_head * head,rcu_callback_t func)839 static void srcu_torture_call(struct rcu_head *head,
840 rcu_callback_t func)
841 {
842 call_srcu(srcu_ctlp, head, func);
843 }
844
srcu_torture_barrier(void)845 static void srcu_torture_barrier(void)
846 {
847 srcu_barrier(srcu_ctlp);
848 }
849
srcu_torture_stats(void)850 static void srcu_torture_stats(void)
851 {
852 srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG);
853 }
854
srcu_torture_synchronize_expedited(void)855 static void srcu_torture_synchronize_expedited(void)
856 {
857 synchronize_srcu_expedited(srcu_ctlp);
858 }
859
860 static struct rcu_torture_ops srcu_ops = {
861 .ttype = SRCU_FLAVOR,
862 .init = rcu_sync_torture_init,
863 .readlock = srcu_torture_read_lock,
864 .read_delay = srcu_read_delay,
865 .readunlock = srcu_torture_read_unlock,
866 .down_read = srcu_torture_down_read,
867 .up_read = srcu_torture_up_read,
868 .readlock_held = torture_srcu_read_lock_held,
869 .get_gp_seq = srcu_torture_completed,
870 .gp_diff = rcu_seq_diff,
871 .deferred_free = srcu_torture_deferred_free,
872 .sync = srcu_torture_synchronize,
873 .exp_sync = srcu_torture_synchronize_expedited,
874 .same_gp_state = same_state_synchronize_srcu,
875 .get_comp_state = get_completed_synchronize_srcu,
876 .get_gp_state = srcu_torture_get_gp_state,
877 .start_gp_poll = srcu_torture_start_gp_poll,
878 .poll_gp_state = srcu_torture_poll_gp_state,
879 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
880 .call = srcu_torture_call,
881 .cb_barrier = srcu_torture_barrier,
882 .stats = srcu_torture_stats,
883 .get_gp_data = srcu_get_gp_data,
884 .cbflood_max = 50000,
885 .irq_capable = 1,
886 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
887 .debug_objects = 1,
888 .have_up_down = IS_ENABLED(CONFIG_TINY_SRCU)
889 ? 0 : SRCU_READ_FLAVOR_NORMAL | SRCU_READ_FLAVOR_FAST,
890 .name = "srcu"
891 };
892
srcu_torture_init(void)893 static void srcu_torture_init(void)
894 {
895 rcu_sync_torture_init();
896 WARN_ON(init_srcu_struct(&srcu_ctld));
897 srcu_ctlp = &srcu_ctld;
898 }
899
srcu_torture_cleanup(void)900 static void srcu_torture_cleanup(void)
901 {
902 cleanup_srcu_struct(&srcu_ctld);
903 srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
904 }
905
906 /* As above, but dynamically allocated. */
907 static struct rcu_torture_ops srcud_ops = {
908 .ttype = SRCU_FLAVOR,
909 .init = srcu_torture_init,
910 .cleanup = srcu_torture_cleanup,
911 .readlock = srcu_torture_read_lock,
912 .read_delay = srcu_read_delay,
913 .readunlock = srcu_torture_read_unlock,
914 .readlock_held = torture_srcu_read_lock_held,
915 .down_read = srcu_torture_down_read,
916 .up_read = srcu_torture_up_read,
917 .get_gp_seq = srcu_torture_completed,
918 .gp_diff = rcu_seq_diff,
919 .deferred_free = srcu_torture_deferred_free,
920 .sync = srcu_torture_synchronize,
921 .exp_sync = srcu_torture_synchronize_expedited,
922 .same_gp_state = same_state_synchronize_srcu,
923 .get_comp_state = get_completed_synchronize_srcu,
924 .get_gp_state = srcu_torture_get_gp_state,
925 .start_gp_poll = srcu_torture_start_gp_poll,
926 .poll_gp_state = srcu_torture_poll_gp_state,
927 .poll_active = NUM_ACTIVE_SRCU_POLL_OLDSTATE,
928 .call = srcu_torture_call,
929 .cb_barrier = srcu_torture_barrier,
930 .stats = srcu_torture_stats,
931 .get_gp_data = srcu_get_gp_data,
932 .cbflood_max = 50000,
933 .irq_capable = 1,
934 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
935 .debug_objects = 1,
936 .have_up_down = IS_ENABLED(CONFIG_TINY_SRCU)
937 ? 0 : SRCU_READ_FLAVOR_NORMAL | SRCU_READ_FLAVOR_FAST,
938 .name = "srcud"
939 };
940
941 /* As above, but broken due to inappropriate reader extension. */
942 static struct rcu_torture_ops busted_srcud_ops = {
943 .ttype = SRCU_FLAVOR,
944 .init = srcu_torture_init,
945 .cleanup = srcu_torture_cleanup,
946 .readlock = srcu_torture_read_lock,
947 .read_delay = rcu_read_delay,
948 .readunlock = srcu_torture_read_unlock,
949 .readlock_held = torture_srcu_read_lock_held,
950 .get_gp_seq = srcu_torture_completed,
951 .deferred_free = srcu_torture_deferred_free,
952 .sync = srcu_torture_synchronize,
953 .exp_sync = srcu_torture_synchronize_expedited,
954 .call = srcu_torture_call,
955 .cb_barrier = srcu_torture_barrier,
956 .stats = srcu_torture_stats,
957 .irq_capable = 1,
958 .no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
959 .extendables = RCUTORTURE_MAX_EXTEND,
960 .name = "busted_srcud"
961 };
962
963 /*
964 * Definitions for trivial CONFIG_PREEMPT=n-only torture testing.
965 * This implementation does not work well with CPU hotplug nor
966 * with rcutorture's shuffling.
967 */
968
synchronize_rcu_trivial(void)969 static void synchronize_rcu_trivial(void)
970 {
971 int cpu;
972
973 for_each_online_cpu(cpu) {
974 torture_sched_setaffinity(current->pid, cpumask_of(cpu), true);
975 WARN_ON_ONCE(raw_smp_processor_id() != cpu);
976 }
977 }
978
rcu_sync_torture_init_trivial(void)979 static void rcu_sync_torture_init_trivial(void)
980 {
981 rcu_sync_torture_init();
982 // if (onoff_interval || shuffle_interval) {
983 if (WARN_ONCE(onoff_interval || shuffle_interval, "%s: Non-zero onoff_interval (%d) or shuffle_interval (%d) breaks trivial RCU, resetting to zero", __func__, onoff_interval, shuffle_interval)) {
984 onoff_interval = 0;
985 shuffle_interval = 0;
986 }
987 }
988
rcu_torture_read_lock_trivial(void)989 static int rcu_torture_read_lock_trivial(void)
990 {
991 preempt_disable();
992 return 0;
993 }
994
rcu_torture_read_unlock_trivial(int idx)995 static void rcu_torture_read_unlock_trivial(int idx)
996 {
997 preempt_enable();
998 }
999
1000 static struct rcu_torture_ops trivial_ops = {
1001 .ttype = RCU_TRIVIAL_FLAVOR,
1002 .init = rcu_sync_torture_init_trivial,
1003 .readlock = rcu_torture_read_lock_trivial,
1004 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
1005 .readunlock = rcu_torture_read_unlock_trivial,
1006 .readlock_held = torture_readlock_not_held,
1007 .get_gp_seq = rcu_no_completed,
1008 .sync = synchronize_rcu_trivial,
1009 .exp_sync = synchronize_rcu_trivial,
1010 .irq_capable = 1,
1011 .name = "trivial"
1012 };
1013
1014 #ifdef CONFIG_TASKS_RCU
1015
1016 /*
1017 * Definitions for RCU-tasks torture testing.
1018 */
1019
tasks_torture_read_lock(void)1020 static int tasks_torture_read_lock(void)
1021 {
1022 return 0;
1023 }
1024
tasks_torture_read_unlock(int idx)1025 static void tasks_torture_read_unlock(int idx)
1026 {
1027 }
1028
rcu_tasks_torture_deferred_free(struct rcu_torture * p)1029 static void rcu_tasks_torture_deferred_free(struct rcu_torture *p)
1030 {
1031 call_rcu_tasks(&p->rtort_rcu, rcu_torture_cb);
1032 }
1033
synchronize_rcu_mult_test(void)1034 static void synchronize_rcu_mult_test(void)
1035 {
1036 synchronize_rcu_mult(call_rcu_tasks, call_rcu_hurry);
1037 }
1038
1039 static struct rcu_torture_ops tasks_ops = {
1040 .ttype = RCU_TASKS_FLAVOR,
1041 .init = rcu_sync_torture_init,
1042 .readlock = tasks_torture_read_lock,
1043 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
1044 .readunlock = tasks_torture_read_unlock,
1045 .get_gp_seq = rcu_no_completed,
1046 .deferred_free = rcu_tasks_torture_deferred_free,
1047 .sync = synchronize_rcu_tasks,
1048 .exp_sync = synchronize_rcu_mult_test,
1049 .call = call_rcu_tasks,
1050 .cb_barrier = rcu_barrier_tasks,
1051 .gp_kthread_dbg = show_rcu_tasks_classic_gp_kthread,
1052 .get_gp_data = rcu_tasks_get_gp_data,
1053 .irq_capable = 1,
1054 .slow_gps = 1,
1055 .name = "tasks"
1056 };
1057
1058 #define TASKS_OPS &tasks_ops,
1059
1060 #else // #ifdef CONFIG_TASKS_RCU
1061
1062 #define TASKS_OPS
1063
1064 #endif // #else #ifdef CONFIG_TASKS_RCU
1065
1066
1067 #ifdef CONFIG_TASKS_RUDE_RCU
1068
1069 /*
1070 * Definitions for rude RCU-tasks torture testing.
1071 */
1072
1073 static struct rcu_torture_ops tasks_rude_ops = {
1074 .ttype = RCU_TASKS_RUDE_FLAVOR,
1075 .init = rcu_sync_torture_init,
1076 .readlock = rcu_torture_read_lock_trivial,
1077 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
1078 .readunlock = rcu_torture_read_unlock_trivial,
1079 .get_gp_seq = rcu_no_completed,
1080 .sync = synchronize_rcu_tasks_rude,
1081 .exp_sync = synchronize_rcu_tasks_rude,
1082 .gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
1083 .get_gp_data = rcu_tasks_rude_get_gp_data,
1084 .cbflood_max = 50000,
1085 .irq_capable = 1,
1086 .name = "tasks-rude"
1087 };
1088
1089 #define TASKS_RUDE_OPS &tasks_rude_ops,
1090
1091 #else // #ifdef CONFIG_TASKS_RUDE_RCU
1092
1093 #define TASKS_RUDE_OPS
1094
1095 #endif // #else #ifdef CONFIG_TASKS_RUDE_RCU
1096
1097
1098 #ifdef CONFIG_TASKS_TRACE_RCU
1099
1100 /*
1101 * Definitions for tracing RCU-tasks torture testing.
1102 */
1103
tasks_tracing_torture_read_lock(void)1104 static int tasks_tracing_torture_read_lock(void)
1105 {
1106 rcu_read_lock_trace();
1107 return 0;
1108 }
1109
tasks_tracing_torture_read_unlock(int idx)1110 static void tasks_tracing_torture_read_unlock(int idx)
1111 {
1112 rcu_read_unlock_trace();
1113 }
1114
rcu_tasks_tracing_torture_deferred_free(struct rcu_torture * p)1115 static void rcu_tasks_tracing_torture_deferred_free(struct rcu_torture *p)
1116 {
1117 call_rcu_tasks_trace(&p->rtort_rcu, rcu_torture_cb);
1118 }
1119
1120 static struct rcu_torture_ops tasks_tracing_ops = {
1121 .ttype = RCU_TASKS_TRACING_FLAVOR,
1122 .init = rcu_sync_torture_init,
1123 .readlock = tasks_tracing_torture_read_lock,
1124 .read_delay = srcu_read_delay, /* just reuse srcu's version. */
1125 .readunlock = tasks_tracing_torture_read_unlock,
1126 .readlock_held = rcu_read_lock_trace_held,
1127 .get_gp_seq = rcu_no_completed,
1128 .deferred_free = rcu_tasks_tracing_torture_deferred_free,
1129 .sync = synchronize_rcu_tasks_trace,
1130 .exp_sync = synchronize_rcu_tasks_trace,
1131 .call = call_rcu_tasks_trace,
1132 .cb_barrier = rcu_barrier_tasks_trace,
1133 .gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
1134 .get_gp_data = rcu_tasks_trace_get_gp_data,
1135 .cbflood_max = 50000,
1136 .irq_capable = 1,
1137 .slow_gps = 1,
1138 .name = "tasks-tracing"
1139 };
1140
1141 #define TASKS_TRACING_OPS &tasks_tracing_ops,
1142
1143 #else // #ifdef CONFIG_TASKS_TRACE_RCU
1144
1145 #define TASKS_TRACING_OPS
1146
1147 #endif // #else #ifdef CONFIG_TASKS_TRACE_RCU
1148
1149
rcutorture_seq_diff(unsigned long new,unsigned long old)1150 static unsigned long rcutorture_seq_diff(unsigned long new, unsigned long old)
1151 {
1152 if (!cur_ops->gp_diff)
1153 return new - old;
1154 return cur_ops->gp_diff(new, old);
1155 }
1156
1157 /*
1158 * RCU torture priority-boost testing. Runs one real-time thread per
1159 * CPU for moderate bursts, repeatedly starting grace periods and waiting
1160 * for them to complete. If a given grace period takes too long, we assume
1161 * that priority inversion has occurred.
1162 */
1163
1164 static int old_rt_runtime = -1;
1165
rcu_torture_disable_rt_throttle(void)1166 static void rcu_torture_disable_rt_throttle(void)
1167 {
1168 /*
1169 * Disable RT throttling so that rcutorture's boost threads don't get
1170 * throttled. Only possible if rcutorture is built-in otherwise the
1171 * user should manually do this by setting the sched_rt_period_us and
1172 * sched_rt_runtime sysctls.
1173 */
1174 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime != -1)
1175 return;
1176
1177 old_rt_runtime = sysctl_sched_rt_runtime;
1178 sysctl_sched_rt_runtime = -1;
1179 }
1180
rcu_torture_enable_rt_throttle(void)1181 static void rcu_torture_enable_rt_throttle(void)
1182 {
1183 if (!IS_BUILTIN(CONFIG_RCU_TORTURE_TEST) || old_rt_runtime == -1)
1184 return;
1185
1186 sysctl_sched_rt_runtime = old_rt_runtime;
1187 old_rt_runtime = -1;
1188 }
1189
rcu_torture_boost_failed(unsigned long gp_state,unsigned long * start)1190 static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
1191 {
1192 int cpu;
1193 static int dbg_done;
1194 unsigned long end = jiffies;
1195 bool gp_done;
1196 unsigned long j;
1197 static unsigned long last_persist;
1198 unsigned long lp;
1199 unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
1200
1201 if (end - *start > mininterval) {
1202 // Recheck after checking time to avoid false positives.
1203 smp_mb(); // Time check before grace-period check.
1204 if (cur_ops->poll_gp_state(gp_state))
1205 return false; // passed, though perhaps just barely
1206 if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
1207 // At most one persisted message per boost test.
1208 j = jiffies;
1209 lp = READ_ONCE(last_persist);
1210 if (time_after(j, lp + mininterval) &&
1211 cmpxchg(&last_persist, lp, j) == lp) {
1212 if (cpu < 0)
1213 pr_info("Boost inversion persisted: QS from all CPUs\n");
1214 else
1215 pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
1216 }
1217 return false; // passed on a technicality
1218 }
1219 VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
1220 n_rcu_torture_boost_failure++;
1221 if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
1222 pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
1223 current->rt_priority, gp_state, end - *start);
1224 cur_ops->gp_kthread_dbg();
1225 // Recheck after print to flag grace period ending during splat.
1226 gp_done = cur_ops->poll_gp_state(gp_state);
1227 pr_info("Boost inversion: GP %lu %s.\n", gp_state,
1228 gp_done ? "ended already" : "still pending");
1229
1230 }
1231
1232 return true; // failed
1233 } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
1234 *start = jiffies;
1235 }
1236
1237 return false; // passed
1238 }
1239
rcu_torture_boost(void * arg)1240 static int rcu_torture_boost(void *arg)
1241 {
1242 unsigned long endtime;
1243 unsigned long gp_state;
1244 unsigned long gp_state_time;
1245 unsigned long oldstarttime;
1246 unsigned long booststarttime = get_torture_init_jiffies() + test_boost_holdoff * HZ;
1247
1248 if (test_boost_holdoff <= 0 || time_after(jiffies, booststarttime)) {
1249 VERBOSE_TOROUT_STRING("rcu_torture_boost started");
1250 } else {
1251 VERBOSE_TOROUT_STRING("rcu_torture_boost started holdoff period");
1252 while (time_before(jiffies, booststarttime)) {
1253 schedule_timeout_idle(HZ);
1254 if (kthread_should_stop())
1255 goto cleanup;
1256 }
1257 VERBOSE_TOROUT_STRING("rcu_torture_boost finished holdoff period");
1258 }
1259
1260 /* Set real-time priority. */
1261 sched_set_fifo_low(current);
1262
1263 /* Each pass through the following loop does one boost-test cycle. */
1264 do {
1265 bool failed = false; // Test failed already in this test interval
1266 bool gp_initiated = false;
1267
1268 if (kthread_should_stop())
1269 goto checkwait;
1270
1271 /* Wait for the next test interval. */
1272 oldstarttime = READ_ONCE(boost_starttime);
1273 while (time_before(jiffies, oldstarttime)) {
1274 schedule_timeout_interruptible(oldstarttime - jiffies);
1275 if (stutter_wait("rcu_torture_boost"))
1276 sched_set_fifo_low(current);
1277 if (torture_must_stop())
1278 goto checkwait;
1279 }
1280
1281 // Do one boost-test interval.
1282 endtime = oldstarttime + test_boost_duration * HZ;
1283 while (time_before(jiffies, endtime)) {
1284 // Has current GP gone too long?
1285 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1286 failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
1287 // If we don't have a grace period in flight, start one.
1288 if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
1289 gp_state = cur_ops->start_gp_poll();
1290 gp_initiated = true;
1291 gp_state_time = jiffies;
1292 }
1293 if (stutter_wait("rcu_torture_boost")) {
1294 sched_set_fifo_low(current);
1295 // If the grace period already ended,
1296 // we don't know when that happened, so
1297 // start over.
1298 if (cur_ops->poll_gp_state(gp_state))
1299 gp_initiated = false;
1300 }
1301 if (torture_must_stop())
1302 goto checkwait;
1303 }
1304
1305 // In case the grace period extended beyond the end of the loop.
1306 if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
1307 rcu_torture_boost_failed(gp_state, &gp_state_time);
1308
1309 /*
1310 * Set the start time of the next test interval.
1311 * Yes, this is vulnerable to long delays, but such
1312 * delays simply cause a false negative for the next
1313 * interval. Besides, we are running at RT priority,
1314 * so delays should be relatively rare.
1315 */
1316 while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
1317 if (mutex_trylock(&boost_mutex)) {
1318 if (oldstarttime == boost_starttime) {
1319 WRITE_ONCE(boost_starttime,
1320 jiffies + test_boost_interval * HZ);
1321 n_rcu_torture_boosts++;
1322 }
1323 mutex_unlock(&boost_mutex);
1324 break;
1325 }
1326 schedule_timeout_uninterruptible(HZ / 20);
1327 }
1328
1329 /* Go do the stutter. */
1330 checkwait: if (stutter_wait("rcu_torture_boost"))
1331 sched_set_fifo_low(current);
1332 } while (!torture_must_stop());
1333
1334 cleanup:
1335 /* Clean up and exit. */
1336 while (!kthread_should_stop()) {
1337 torture_shutdown_absorb("rcu_torture_boost");
1338 schedule_timeout_uninterruptible(HZ / 20);
1339 }
1340 torture_kthread_stopping("rcu_torture_boost");
1341 return 0;
1342 }
1343
1344 /*
1345 * RCU torture force-quiescent-state kthread. Repeatedly induces
1346 * bursts of calls to force_quiescent_state(), increasing the probability
1347 * of occurrence of some important types of race conditions.
1348 */
1349 static int
rcu_torture_fqs(void * arg)1350 rcu_torture_fqs(void *arg)
1351 {
1352 unsigned long fqs_resume_time;
1353 int fqs_burst_remaining;
1354 int oldnice = task_nice(current);
1355
1356 VERBOSE_TOROUT_STRING("rcu_torture_fqs task started");
1357 do {
1358 fqs_resume_time = jiffies + fqs_stutter * HZ;
1359 while (time_before(jiffies, fqs_resume_time) &&
1360 !kthread_should_stop()) {
1361 schedule_timeout_interruptible(HZ / 20);
1362 }
1363 fqs_burst_remaining = fqs_duration;
1364 while (fqs_burst_remaining > 0 &&
1365 !kthread_should_stop()) {
1366 cur_ops->fqs();
1367 udelay(fqs_holdoff);
1368 fqs_burst_remaining -= fqs_holdoff;
1369 }
1370 if (stutter_wait("rcu_torture_fqs"))
1371 sched_set_normal(current, oldnice);
1372 } while (!torture_must_stop());
1373 torture_kthread_stopping("rcu_torture_fqs");
1374 return 0;
1375 }
1376
1377 // Used by writers to randomly choose from the available grace-period primitives.
1378 static int synctype[ARRAY_SIZE(rcu_torture_writer_state_names)] = { };
1379 static int nsynctypes;
1380
1381 /*
1382 * Determine which grace-period primitives are available.
1383 */
rcu_torture_write_types(void)1384 static void rcu_torture_write_types(void)
1385 {
1386 bool gp_cond1 = gp_cond, gp_cond_exp1 = gp_cond_exp, gp_cond_full1 = gp_cond_full;
1387 bool gp_cond_exp_full1 = gp_cond_exp_full, gp_exp1 = gp_exp, gp_poll_exp1 = gp_poll_exp;
1388 bool gp_poll_exp_full1 = gp_poll_exp_full, gp_normal1 = gp_normal, gp_poll1 = gp_poll;
1389 bool gp_poll_full1 = gp_poll_full, gp_sync1 = gp_sync;
1390
1391 /* Initialize synctype[] array. If none set, take default. */
1392 if (!gp_cond1 &&
1393 !gp_cond_exp1 &&
1394 !gp_cond_full1 &&
1395 !gp_cond_exp_full1 &&
1396 !gp_exp1 &&
1397 !gp_poll_exp1 &&
1398 !gp_poll_exp_full1 &&
1399 !gp_normal1 &&
1400 !gp_poll1 &&
1401 !gp_poll_full1 &&
1402 !gp_sync1) {
1403 gp_cond1 = true;
1404 gp_cond_exp1 = true;
1405 gp_cond_full1 = true;
1406 gp_cond_exp_full1 = true;
1407 gp_exp1 = true;
1408 gp_poll_exp1 = true;
1409 gp_poll_exp_full1 = true;
1410 gp_normal1 = true;
1411 gp_poll1 = true;
1412 gp_poll_full1 = true;
1413 gp_sync1 = true;
1414 }
1415 if (gp_cond1 && cur_ops->get_gp_state && cur_ops->cond_sync) {
1416 synctype[nsynctypes++] = RTWS_COND_GET;
1417 pr_info("%s: Testing conditional GPs.\n", __func__);
1418 } else if (gp_cond && (!cur_ops->get_gp_state || !cur_ops->cond_sync)) {
1419 pr_alert("%s: gp_cond without primitives.\n", __func__);
1420 }
1421 if (gp_cond_exp1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp) {
1422 synctype[nsynctypes++] = RTWS_COND_GET_EXP;
1423 pr_info("%s: Testing conditional expedited GPs.\n", __func__);
1424 } else if (gp_cond_exp && (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp)) {
1425 pr_alert("%s: gp_cond_exp without primitives.\n", __func__);
1426 }
1427 if (gp_cond_full1 && cur_ops->get_gp_state && cur_ops->cond_sync_full) {
1428 synctype[nsynctypes++] = RTWS_COND_GET_FULL;
1429 pr_info("%s: Testing conditional full-state GPs.\n", __func__);
1430 } else if (gp_cond_full && (!cur_ops->get_gp_state || !cur_ops->cond_sync_full)) {
1431 pr_alert("%s: gp_cond_full without primitives.\n", __func__);
1432 }
1433 if (gp_cond_exp_full1 && cur_ops->get_gp_state_exp && cur_ops->cond_sync_exp_full) {
1434 synctype[nsynctypes++] = RTWS_COND_GET_EXP_FULL;
1435 pr_info("%s: Testing conditional full-state expedited GPs.\n", __func__);
1436 } else if (gp_cond_exp_full &&
1437 (!cur_ops->get_gp_state_exp || !cur_ops->cond_sync_exp_full)) {
1438 pr_alert("%s: gp_cond_exp_full without primitives.\n", __func__);
1439 }
1440 if (gp_exp1 && cur_ops->exp_sync) {
1441 synctype[nsynctypes++] = RTWS_EXP_SYNC;
1442 pr_info("%s: Testing expedited GPs.\n", __func__);
1443 } else if (gp_exp && !cur_ops->exp_sync) {
1444 pr_alert("%s: gp_exp without primitives.\n", __func__);
1445 }
1446 if (gp_normal1 && cur_ops->deferred_free) {
1447 synctype[nsynctypes++] = RTWS_DEF_FREE;
1448 pr_info("%s: Testing asynchronous GPs.\n", __func__);
1449 } else if (gp_normal && !cur_ops->deferred_free) {
1450 pr_alert("%s: gp_normal without primitives.\n", __func__);
1451 }
1452 if (gp_poll1 && cur_ops->get_comp_state && cur_ops->same_gp_state &&
1453 cur_ops->start_gp_poll && cur_ops->poll_gp_state) {
1454 synctype[nsynctypes++] = RTWS_POLL_GET;
1455 pr_info("%s: Testing polling GPs.\n", __func__);
1456 } else if (gp_poll && (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)) {
1457 pr_alert("%s: gp_poll without primitives.\n", __func__);
1458 }
1459 if (gp_poll_full1 && cur_ops->get_comp_state_full && cur_ops->same_gp_state_full
1460 && cur_ops->start_gp_poll_full && cur_ops->poll_gp_state_full) {
1461 synctype[nsynctypes++] = RTWS_POLL_GET_FULL;
1462 pr_info("%s: Testing polling full-state GPs.\n", __func__);
1463 } else if (gp_poll_full && (!cur_ops->start_gp_poll_full || !cur_ops->poll_gp_state_full)) {
1464 pr_alert("%s: gp_poll_full without primitives.\n", __func__);
1465 }
1466 if (gp_poll_exp1 && cur_ops->start_gp_poll_exp && cur_ops->poll_gp_state_exp) {
1467 synctype[nsynctypes++] = RTWS_POLL_GET_EXP;
1468 pr_info("%s: Testing polling expedited GPs.\n", __func__);
1469 } else if (gp_poll_exp && (!cur_ops->start_gp_poll_exp || !cur_ops->poll_gp_state_exp)) {
1470 pr_alert("%s: gp_poll_exp without primitives.\n", __func__);
1471 }
1472 if (gp_poll_exp_full1 && cur_ops->start_gp_poll_exp_full && cur_ops->poll_gp_state_full) {
1473 synctype[nsynctypes++] = RTWS_POLL_GET_EXP_FULL;
1474 pr_info("%s: Testing polling full-state expedited GPs.\n", __func__);
1475 } else if (gp_poll_exp_full &&
1476 (!cur_ops->start_gp_poll_exp_full || !cur_ops->poll_gp_state_full)) {
1477 pr_alert("%s: gp_poll_exp_full without primitives.\n", __func__);
1478 }
1479 if (gp_sync1 && cur_ops->sync) {
1480 synctype[nsynctypes++] = RTWS_SYNC;
1481 pr_info("%s: Testing normal GPs.\n", __func__);
1482 } else if (gp_sync && !cur_ops->sync) {
1483 pr_alert("%s: gp_sync without primitives.\n", __func__);
1484 }
1485 pr_alert("%s: Testing %d update types.\n", __func__, nsynctypes);
1486 pr_info("%s: gp_cond_wi %d gp_cond_wi_exp %d gp_poll_wi %d gp_poll_wi_exp %d\n", __func__, gp_cond_wi, gp_cond_wi_exp, gp_poll_wi, gp_poll_wi_exp);
1487 }
1488
1489 /*
1490 * Do the specified rcu_torture_writer() synchronous grace period,
1491 * while also testing out the polled APIs. Note well that the single-CPU
1492 * grace-period optimizations must be accounted for.
1493 */
do_rtws_sync(struct torture_random_state * trsp,void (* sync)(void))1494 static void do_rtws_sync(struct torture_random_state *trsp, void (*sync)(void))
1495 {
1496 unsigned long cookie;
1497 struct rcu_gp_oldstate cookie_full;
1498 bool dopoll;
1499 bool dopoll_full;
1500 unsigned long r = torture_random(trsp);
1501
1502 dopoll = cur_ops->get_gp_state && cur_ops->poll_gp_state && !(r & 0x300);
1503 dopoll_full = cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full && !(r & 0xc00);
1504 if (dopoll || dopoll_full)
1505 cpus_read_lock();
1506 if (dopoll)
1507 cookie = cur_ops->get_gp_state();
1508 if (dopoll_full)
1509 cur_ops->get_gp_state_full(&cookie_full);
1510 if (cur_ops->poll_need_2gp && cur_ops->poll_need_2gp(dopoll, dopoll_full))
1511 sync();
1512 sync();
1513 WARN_ONCE(dopoll && !cur_ops->poll_gp_state(cookie),
1514 "%s: Cookie check 3 failed %pS() online %*pbl.",
1515 __func__, sync, cpumask_pr_args(cpu_online_mask));
1516 WARN_ONCE(dopoll_full && !cur_ops->poll_gp_state_full(&cookie_full),
1517 "%s: Cookie check 4 failed %pS() online %*pbl",
1518 __func__, sync, cpumask_pr_args(cpu_online_mask));
1519 if (dopoll || dopoll_full)
1520 cpus_read_unlock();
1521 }
1522
1523 /*
1524 * RCU torture writer kthread. Repeatedly substitutes a new structure
1525 * for that pointed to by rcu_torture_current, freeing the old structure
1526 * after a series of grace periods (the "pipeline").
1527 */
1528 static int
rcu_torture_writer(void * arg)1529 rcu_torture_writer(void *arg)
1530 {
1531 bool boot_ended;
1532 bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal();
1533 unsigned long cookie;
1534 struct rcu_gp_oldstate cookie_full;
1535 int expediting = 0;
1536 unsigned long gp_snap;
1537 unsigned long gp_snap1;
1538 struct rcu_gp_oldstate gp_snap_full;
1539 struct rcu_gp_oldstate gp_snap1_full;
1540 int i;
1541 int idx;
1542 int oldnice = task_nice(current);
1543 struct rcu_gp_oldstate *rgo = NULL;
1544 int rgo_size = 0;
1545 struct rcu_torture *rp;
1546 struct rcu_torture *old_rp;
1547 static DEFINE_TORTURE_RANDOM(rand);
1548 unsigned long stallsdone = jiffies;
1549 bool stutter_waited;
1550 unsigned long *ulo = NULL;
1551 int ulo_size = 0;
1552
1553 // If a new stall test is added, this must be adjusted.
1554 if (stall_cpu_holdoff + stall_gp_kthread + stall_cpu)
1555 stallsdone += (stall_cpu_holdoff + stall_gp_kthread + stall_cpu + 60) *
1556 HZ * (stall_cpu_repeat + 1);
1557 VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
1558 if (!can_expedite)
1559 pr_alert("%s" TORTURE_FLAG
1560 " GP expediting controlled from boot/sysfs for %s.\n",
1561 torture_type, cur_ops->name);
1562 if (WARN_ONCE(nsynctypes == 0,
1563 "%s: No update-side primitives.\n", __func__)) {
1564 /*
1565 * No updates primitives, so don't try updating.
1566 * The resulting test won't be testing much, hence the
1567 * above WARN_ONCE().
1568 */
1569 rcu_torture_writer_state = RTWS_STOPPING;
1570 torture_kthread_stopping("rcu_torture_writer");
1571 return 0;
1572 }
1573 if (cur_ops->poll_active > 0) {
1574 ulo = kzalloc(cur_ops->poll_active * sizeof(ulo[0]), GFP_KERNEL);
1575 if (!WARN_ON(!ulo))
1576 ulo_size = cur_ops->poll_active;
1577 }
1578 if (cur_ops->poll_active_full > 0) {
1579 rgo = kzalloc(cur_ops->poll_active_full * sizeof(rgo[0]), GFP_KERNEL);
1580 if (!WARN_ON(!rgo))
1581 rgo_size = cur_ops->poll_active_full;
1582 }
1583
1584 do {
1585 rcu_torture_writer_state = RTWS_FIXED_DELAY;
1586 torture_hrtimeout_us(500, 1000, &rand);
1587 rp = rcu_torture_alloc();
1588 if (rp == NULL)
1589 continue;
1590 rp->rtort_pipe_count = 0;
1591 ASSERT_EXCLUSIVE_WRITER(rp->rtort_pipe_count);
1592 rcu_torture_writer_state = RTWS_DELAY;
1593 udelay(torture_random(&rand) & 0x3ff);
1594 rcu_torture_writer_state = RTWS_REPLACE;
1595 old_rp = rcu_dereference_check(rcu_torture_current,
1596 current == writer_task);
1597 rp->rtort_mbtest = 1;
1598 rcu_assign_pointer(rcu_torture_current, rp);
1599 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
1600 if (old_rp) {
1601 i = old_rp->rtort_pipe_count;
1602 if (i > RCU_TORTURE_PIPE_LEN)
1603 i = RCU_TORTURE_PIPE_LEN;
1604 atomic_inc(&rcu_torture_wcount[i]);
1605 WRITE_ONCE(old_rp->rtort_pipe_count,
1606 old_rp->rtort_pipe_count + 1);
1607 ASSERT_EXCLUSIVE_WRITER(old_rp->rtort_pipe_count);
1608
1609 // Make sure readers block polled grace periods.
1610 if (cur_ops->get_gp_state && cur_ops->poll_gp_state) {
1611 idx = cur_ops->readlock();
1612 cookie = cur_ops->get_gp_state();
1613 WARN_ONCE(cur_ops->poll_gp_state(cookie),
1614 "%s: Cookie check 1 failed %s(%d) %lu->%lu\n",
1615 __func__,
1616 rcu_torture_writer_state_getname(),
1617 rcu_torture_writer_state,
1618 cookie, cur_ops->get_gp_state());
1619 if (cur_ops->get_comp_state) {
1620 cookie = cur_ops->get_comp_state();
1621 WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
1622 }
1623 cur_ops->readunlock(idx);
1624 }
1625 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) {
1626 idx = cur_ops->readlock();
1627 cur_ops->get_gp_state_full(&cookie_full);
1628 WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
1629 "%s: Cookie check 5 failed %s(%d) online %*pbl\n",
1630 __func__,
1631 rcu_torture_writer_state_getname(),
1632 rcu_torture_writer_state,
1633 cpumask_pr_args(cpu_online_mask));
1634 if (cur_ops->get_comp_state_full) {
1635 cur_ops->get_comp_state_full(&cookie_full);
1636 WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full));
1637 }
1638 cur_ops->readunlock(idx);
1639 }
1640 switch (synctype[torture_random(&rand) % nsynctypes]) {
1641 case RTWS_DEF_FREE:
1642 rcu_torture_writer_state = RTWS_DEF_FREE;
1643 cur_ops->deferred_free(old_rp);
1644 break;
1645 case RTWS_EXP_SYNC:
1646 rcu_torture_writer_state = RTWS_EXP_SYNC;
1647 do_rtws_sync(&rand, cur_ops->exp_sync);
1648 rcu_torture_pipe_update(old_rp);
1649 break;
1650 case RTWS_COND_GET:
1651 rcu_torture_writer_state = RTWS_COND_GET;
1652 gp_snap = cur_ops->get_gp_state();
1653 torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi,
1654 1000, &rand);
1655 rcu_torture_writer_state = RTWS_COND_SYNC;
1656 cur_ops->cond_sync(gp_snap);
1657 rcu_torture_pipe_update(old_rp);
1658 break;
1659 case RTWS_COND_GET_EXP:
1660 rcu_torture_writer_state = RTWS_COND_GET_EXP;
1661 gp_snap = cur_ops->get_gp_state_exp();
1662 torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi_exp,
1663 1000, &rand);
1664 rcu_torture_writer_state = RTWS_COND_SYNC_EXP;
1665 cur_ops->cond_sync_exp(gp_snap);
1666 rcu_torture_pipe_update(old_rp);
1667 break;
1668 case RTWS_COND_GET_FULL:
1669 rcu_torture_writer_state = RTWS_COND_GET_FULL;
1670 cur_ops->get_gp_state_full(&gp_snap_full);
1671 torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi,
1672 1000, &rand);
1673 rcu_torture_writer_state = RTWS_COND_SYNC_FULL;
1674 cur_ops->cond_sync_full(&gp_snap_full);
1675 rcu_torture_pipe_update(old_rp);
1676 break;
1677 case RTWS_COND_GET_EXP_FULL:
1678 rcu_torture_writer_state = RTWS_COND_GET_EXP_FULL;
1679 cur_ops->get_gp_state_full(&gp_snap_full);
1680 torture_hrtimeout_us(torture_random(&rand) % gp_cond_wi_exp,
1681 1000, &rand);
1682 rcu_torture_writer_state = RTWS_COND_SYNC_EXP_FULL;
1683 cur_ops->cond_sync_exp_full(&gp_snap_full);
1684 rcu_torture_pipe_update(old_rp);
1685 break;
1686 case RTWS_POLL_GET:
1687 rcu_torture_writer_state = RTWS_POLL_GET;
1688 for (i = 0; i < ulo_size; i++)
1689 ulo[i] = cur_ops->get_comp_state();
1690 gp_snap = cur_ops->start_gp_poll();
1691 rcu_torture_writer_state = RTWS_POLL_WAIT;
1692 while (!cur_ops->poll_gp_state(gp_snap)) {
1693 gp_snap1 = cur_ops->get_gp_state();
1694 for (i = 0; i < ulo_size; i++)
1695 if (cur_ops->poll_gp_state(ulo[i]) ||
1696 cur_ops->same_gp_state(ulo[i], gp_snap1)) {
1697 ulo[i] = gp_snap1;
1698 break;
1699 }
1700 WARN_ON_ONCE(ulo_size > 0 && i >= ulo_size);
1701 torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi,
1702 1000, &rand);
1703 }
1704 rcu_torture_pipe_update(old_rp);
1705 break;
1706 case RTWS_POLL_GET_FULL:
1707 rcu_torture_writer_state = RTWS_POLL_GET_FULL;
1708 for (i = 0; i < rgo_size; i++)
1709 cur_ops->get_comp_state_full(&rgo[i]);
1710 cur_ops->start_gp_poll_full(&gp_snap_full);
1711 rcu_torture_writer_state = RTWS_POLL_WAIT_FULL;
1712 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1713 cur_ops->get_gp_state_full(&gp_snap1_full);
1714 for (i = 0; i < rgo_size; i++)
1715 if (cur_ops->poll_gp_state_full(&rgo[i]) ||
1716 cur_ops->same_gp_state_full(&rgo[i],
1717 &gp_snap1_full)) {
1718 rgo[i] = gp_snap1_full;
1719 break;
1720 }
1721 WARN_ON_ONCE(rgo_size > 0 && i >= rgo_size);
1722 torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi,
1723 1000, &rand);
1724 }
1725 rcu_torture_pipe_update(old_rp);
1726 break;
1727 case RTWS_POLL_GET_EXP:
1728 rcu_torture_writer_state = RTWS_POLL_GET_EXP;
1729 gp_snap = cur_ops->start_gp_poll_exp();
1730 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;
1731 while (!cur_ops->poll_gp_state_exp(gp_snap))
1732 torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi_exp,
1733 1000, &rand);
1734 rcu_torture_pipe_update(old_rp);
1735 break;
1736 case RTWS_POLL_GET_EXP_FULL:
1737 rcu_torture_writer_state = RTWS_POLL_GET_EXP_FULL;
1738 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1739 rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;
1740 while (!cur_ops->poll_gp_state_full(&gp_snap_full))
1741 torture_hrtimeout_us(torture_random(&rand) % gp_poll_wi_exp,
1742 1000, &rand);
1743 rcu_torture_pipe_update(old_rp);
1744 break;
1745 case RTWS_SYNC:
1746 rcu_torture_writer_state = RTWS_SYNC;
1747 do_rtws_sync(&rand, cur_ops->sync);
1748 rcu_torture_pipe_update(old_rp);
1749 break;
1750 default:
1751 WARN_ON_ONCE(1);
1752 break;
1753 }
1754 }
1755 WRITE_ONCE(rcu_torture_current_version,
1756 rcu_torture_current_version + 1);
1757 /* Cycle through nesting levels of rcu_expedite_gp() calls. */
1758 if (can_expedite &&
1759 !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
1760 WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
1761 if (expediting >= 0)
1762 rcu_expedite_gp();
1763 else
1764 rcu_unexpedite_gp();
1765 if (++expediting > 3)
1766 expediting = -expediting;
1767 } else if (!can_expedite) { /* Disabled during boot, recheck. */
1768 can_expedite = !rcu_gp_is_expedited() &&
1769 !rcu_gp_is_normal();
1770 }
1771 rcu_torture_writer_state = RTWS_STUTTER;
1772 boot_ended = rcu_inkernel_boot_has_ended();
1773 stutter_waited = stutter_wait("rcu_torture_writer");
1774 if (stutter_waited &&
1775 !atomic_read(&rcu_fwd_cb_nodelay) &&
1776 !cur_ops->slow_gps &&
1777 !torture_must_stop() &&
1778 boot_ended &&
1779 time_after(jiffies, stallsdone))
1780 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++)
1781 if (list_empty(&rcu_tortures[i].rtort_free) &&
1782 rcu_access_pointer(rcu_torture_current) != &rcu_tortures[i]) {
1783 tracing_off();
1784 if (cur_ops->gp_kthread_dbg)
1785 cur_ops->gp_kthread_dbg();
1786 WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
1787 rcu_ftrace_dump(DUMP_ALL);
1788 break;
1789 }
1790 if (stutter_waited)
1791 sched_set_normal(current, oldnice);
1792 } while (!torture_must_stop());
1793 rcu_torture_current = NULL; // Let stats task know that we are done.
1794 /* Reset expediting back to unexpedited. */
1795 if (expediting > 0)
1796 expediting = -expediting;
1797 while (can_expedite && expediting++ < 0)
1798 rcu_unexpedite_gp();
1799 WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
1800 if (!can_expedite)
1801 pr_alert("%s" TORTURE_FLAG
1802 " Dynamic grace-period expediting was disabled.\n",
1803 torture_type);
1804 kfree(ulo);
1805 kfree(rgo);
1806 rcu_torture_writer_state = RTWS_STOPPING;
1807 torture_kthread_stopping("rcu_torture_writer");
1808 return 0;
1809 }
1810
1811 /*
1812 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1813 * delay between calls.
1814 */
1815 static int
rcu_torture_fakewriter(void * arg)1816 rcu_torture_fakewriter(void *arg)
1817 {
1818 unsigned long gp_snap;
1819 struct rcu_gp_oldstate gp_snap_full;
1820 DEFINE_TORTURE_RANDOM(rand);
1821
1822 VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task started");
1823 set_user_nice(current, MAX_NICE);
1824
1825 if (WARN_ONCE(nsynctypes == 0,
1826 "%s: No update-side primitives.\n", __func__)) {
1827 /*
1828 * No updates primitives, so don't try updating.
1829 * The resulting test won't be testing much, hence the
1830 * above WARN_ONCE().
1831 */
1832 torture_kthread_stopping("rcu_torture_fakewriter");
1833 return 0;
1834 }
1835
1836 do {
1837 torture_hrtimeout_jiffies(torture_random(&rand) % 10, &rand);
1838 if (cur_ops->cb_barrier != NULL &&
1839 torture_random(&rand) % (nrealfakewriters * 8) == 0) {
1840 cur_ops->cb_barrier();
1841 } else {
1842 switch (synctype[torture_random(&rand) % nsynctypes]) {
1843 case RTWS_DEF_FREE:
1844 break;
1845 case RTWS_EXP_SYNC:
1846 cur_ops->exp_sync();
1847 break;
1848 case RTWS_COND_GET:
1849 gp_snap = cur_ops->get_gp_state();
1850 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1851 cur_ops->cond_sync(gp_snap);
1852 break;
1853 case RTWS_COND_GET_EXP:
1854 gp_snap = cur_ops->get_gp_state_exp();
1855 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1856 cur_ops->cond_sync_exp(gp_snap);
1857 break;
1858 case RTWS_COND_GET_FULL:
1859 cur_ops->get_gp_state_full(&gp_snap_full);
1860 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1861 cur_ops->cond_sync_full(&gp_snap_full);
1862 break;
1863 case RTWS_COND_GET_EXP_FULL:
1864 cur_ops->get_gp_state_full(&gp_snap_full);
1865 torture_hrtimeout_jiffies(torture_random(&rand) % 16, &rand);
1866 cur_ops->cond_sync_exp_full(&gp_snap_full);
1867 break;
1868 case RTWS_POLL_GET:
1869 if (cur_ops->start_poll_irqsoff)
1870 local_irq_disable();
1871 gp_snap = cur_ops->start_gp_poll();
1872 if (cur_ops->start_poll_irqsoff)
1873 local_irq_enable();
1874 while (!cur_ops->poll_gp_state(gp_snap)) {
1875 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1876 &rand);
1877 }
1878 break;
1879 case RTWS_POLL_GET_FULL:
1880 if (cur_ops->start_poll_irqsoff)
1881 local_irq_disable();
1882 cur_ops->start_gp_poll_full(&gp_snap_full);
1883 if (cur_ops->start_poll_irqsoff)
1884 local_irq_enable();
1885 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1886 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1887 &rand);
1888 }
1889 break;
1890 case RTWS_POLL_GET_EXP:
1891 gp_snap = cur_ops->start_gp_poll_exp();
1892 while (!cur_ops->poll_gp_state_exp(gp_snap)) {
1893 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1894 &rand);
1895 }
1896 break;
1897 case RTWS_POLL_GET_EXP_FULL:
1898 cur_ops->start_gp_poll_exp_full(&gp_snap_full);
1899 while (!cur_ops->poll_gp_state_full(&gp_snap_full)) {
1900 torture_hrtimeout_jiffies(torture_random(&rand) % 16,
1901 &rand);
1902 }
1903 break;
1904 case RTWS_SYNC:
1905 cur_ops->sync();
1906 break;
1907 default:
1908 WARN_ON_ONCE(1);
1909 break;
1910 }
1911 }
1912 stutter_wait("rcu_torture_fakewriter");
1913 } while (!torture_must_stop());
1914
1915 torture_kthread_stopping("rcu_torture_fakewriter");
1916 return 0;
1917 }
1918
rcu_torture_timer_cb(struct rcu_head * rhp)1919 static void rcu_torture_timer_cb(struct rcu_head *rhp)
1920 {
1921 kfree(rhp);
1922 }
1923
1924 // Set up and carry out testing of RCU's global memory ordering
rcu_torture_reader_do_mbchk(long myid,struct rcu_torture * rtp,struct torture_random_state * trsp)1925 static void rcu_torture_reader_do_mbchk(long myid, struct rcu_torture *rtp,
1926 struct torture_random_state *trsp)
1927 {
1928 unsigned long loops;
1929 int noc = torture_num_online_cpus();
1930 int rdrchked;
1931 int rdrchker;
1932 struct rcu_torture_reader_check *rtrcp; // Me.
1933 struct rcu_torture_reader_check *rtrcp_assigner; // Assigned us to do checking.
1934 struct rcu_torture_reader_check *rtrcp_chked; // Reader being checked.
1935 struct rcu_torture_reader_check *rtrcp_chker; // Reader doing checking when not me.
1936
1937 if (myid < 0)
1938 return; // Don't try this from timer handlers.
1939
1940 // Increment my counter.
1941 rtrcp = &rcu_torture_reader_mbchk[myid];
1942 WRITE_ONCE(rtrcp->rtc_myloops, rtrcp->rtc_myloops + 1);
1943
1944 // Attempt to assign someone else some checking work.
1945 rdrchked = torture_random(trsp) % nrealreaders;
1946 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1947 rdrchker = torture_random(trsp) % nrealreaders;
1948 rtrcp_chker = &rcu_torture_reader_mbchk[rdrchker];
1949 if (rdrchked != myid && rdrchked != rdrchker && noc >= rdrchked && noc >= rdrchker &&
1950 smp_load_acquire(&rtrcp->rtc_chkrdr) < 0 && // Pairs with smp_store_release below.
1951 !READ_ONCE(rtp->rtort_chkp) &&
1952 !smp_load_acquire(&rtrcp_chker->rtc_assigner)) { // Pairs with smp_store_release below.
1953 rtrcp->rtc_chkloops = READ_ONCE(rtrcp_chked->rtc_myloops);
1954 WARN_ON_ONCE(rtrcp->rtc_chkrdr >= 0);
1955 rtrcp->rtc_chkrdr = rdrchked;
1956 WARN_ON_ONCE(rtrcp->rtc_ready); // This gets set after the grace period ends.
1957 if (cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, NULL, rtrcp) ||
1958 cmpxchg_relaxed(&rtp->rtort_chkp, NULL, rtrcp))
1959 (void)cmpxchg_relaxed(&rtrcp_chker->rtc_assigner, rtrcp, NULL); // Back out.
1960 }
1961
1962 // If assigned some completed work, do it!
1963 rtrcp_assigner = READ_ONCE(rtrcp->rtc_assigner);
1964 if (!rtrcp_assigner || !smp_load_acquire(&rtrcp_assigner->rtc_ready))
1965 return; // No work or work not yet ready.
1966 rdrchked = rtrcp_assigner->rtc_chkrdr;
1967 if (WARN_ON_ONCE(rdrchked < 0))
1968 return;
1969 rtrcp_chked = &rcu_torture_reader_mbchk[rdrchked];
1970 loops = READ_ONCE(rtrcp_chked->rtc_myloops);
1971 atomic_inc(&n_rcu_torture_mbchk_tries);
1972 if (ULONG_CMP_LT(loops, rtrcp_assigner->rtc_chkloops))
1973 atomic_inc(&n_rcu_torture_mbchk_fail);
1974 rtrcp_assigner->rtc_chkloops = loops + ULONG_MAX / 2;
1975 rtrcp_assigner->rtc_ready = 0;
1976 smp_store_release(&rtrcp->rtc_assigner, NULL); // Someone else can assign us work.
1977 smp_store_release(&rtrcp_assigner->rtc_chkrdr, -1); // Assigner can again assign.
1978 }
1979
1980 // Verify the specified RCUTORTURE_RDR* state.
1981 #define ROEC_ARGS "%s %s: Current %#x To add %#x To remove %#x preempt_count() %#x\n", __func__, s, curstate, new, old, preempt_count()
rcutorture_one_extend_check(char * s,int curstate,int new,int old)1982 static void rcutorture_one_extend_check(char *s, int curstate, int new, int old)
1983 {
1984 int mask;
1985
1986 if (!IS_ENABLED(CONFIG_RCU_TORTURE_TEST_CHK_RDR_STATE) || in_nmi())
1987 return;
1988
1989 WARN_ONCE(!(curstate & RCUTORTURE_RDR_IRQ) && irqs_disabled() && !in_hardirq(), ROEC_ARGS);
1990 WARN_ONCE((curstate & RCUTORTURE_RDR_IRQ) && !irqs_disabled(), ROEC_ARGS);
1991
1992 // If CONFIG_PREEMPT_COUNT=n, further checks are unreliable.
1993 if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
1994 return;
1995
1996 WARN_ONCE((curstate & (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH)) &&
1997 !softirq_count(), ROEC_ARGS);
1998 WARN_ONCE((curstate & (RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED)) &&
1999 !(preempt_count() & PREEMPT_MASK), ROEC_ARGS);
2000 WARN_ONCE(cur_ops->readlock_nesting &&
2001 (curstate & (RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2)) &&
2002 cur_ops->readlock_nesting() == 0, ROEC_ARGS);
2003
2004 // Interrupt handlers have all sorts of stuff disabled, so ignore
2005 // unintended disabling.
2006 if (in_serving_softirq() || in_hardirq())
2007 return;
2008
2009 WARN_ONCE(cur_ops->extendables &&
2010 !(curstate & (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH)) &&
2011 softirq_count(), ROEC_ARGS);
2012
2013 /*
2014 * non-preemptible RCU in a preemptible kernel uses preempt_disable()
2015 * as rcu_read_lock().
2016 */
2017 mask = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
2018 if (!IS_ENABLED(CONFIG_PREEMPT_RCU))
2019 mask |= RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
2020
2021 WARN_ONCE(cur_ops->extendables && !(curstate & mask) &&
2022 (preempt_count() & PREEMPT_MASK), ROEC_ARGS);
2023
2024 /*
2025 * non-preemptible RCU in a preemptible kernel uses "preempt_count() &
2026 * PREEMPT_MASK" as ->readlock_nesting().
2027 */
2028 mask = RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
2029 if (!IS_ENABLED(CONFIG_PREEMPT_RCU))
2030 mask |= RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
2031
2032 if (IS_ENABLED(CONFIG_PREEMPT_RT) && softirq_count())
2033 mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
2034
2035 WARN_ONCE(cur_ops->readlock_nesting && !(curstate & mask) &&
2036 cur_ops->readlock_nesting() > 0, ROEC_ARGS);
2037 }
2038
2039 /*
2040 * Do one extension of an RCU read-side critical section using the
2041 * current reader state in readstate (set to zero for initial entry
2042 * to extended critical section), set the new state as specified by
2043 * newstate (set to zero for final exit from extended critical section),
2044 * and random-number-generator state in trsp. If this is neither the
2045 * beginning or end of the critical section and if there was actually a
2046 * change, do a ->read_delay().
2047 */
rcutorture_one_extend(int * readstate,int newstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)2048 static void rcutorture_one_extend(int *readstate, int newstate, struct torture_random_state *trsp,
2049 struct rt_read_seg *rtrsp)
2050 {
2051 bool first;
2052 unsigned long flags;
2053 int idxnew1 = -1;
2054 int idxnew2 = -1;
2055 int idxold1 = *readstate;
2056 int idxold2 = idxold1;
2057 int statesnew = ~*readstate & newstate;
2058 int statesold = *readstate & ~newstate;
2059
2060 first = idxold1 == 0;
2061 WARN_ON_ONCE(idxold2 < 0);
2062 WARN_ON_ONCE(idxold2 & ~(RCUTORTURE_RDR_ALLBITS | RCUTORTURE_RDR_UPDOWN));
2063 rcutorture_one_extend_check("before change", idxold1, statesnew, statesold);
2064 rtrsp->rt_readstate = newstate;
2065
2066 /* First, put new protection in place to avoid critical-section gap. */
2067 if (statesnew & RCUTORTURE_RDR_BH)
2068 local_bh_disable();
2069 if (statesnew & RCUTORTURE_RDR_RBH)
2070 rcu_read_lock_bh();
2071 if (statesnew & RCUTORTURE_RDR_IRQ)
2072 local_irq_disable();
2073 if (statesnew & RCUTORTURE_RDR_PREEMPT)
2074 preempt_disable();
2075 if (statesnew & RCUTORTURE_RDR_SCHED)
2076 rcu_read_lock_sched();
2077 if (statesnew & RCUTORTURE_RDR_RCU_1)
2078 idxnew1 = (cur_ops->readlock() << RCUTORTURE_RDR_SHIFT_1) & RCUTORTURE_RDR_MASK_1;
2079 if (statesnew & RCUTORTURE_RDR_RCU_2)
2080 idxnew2 = (cur_ops->readlock() << RCUTORTURE_RDR_SHIFT_2) & RCUTORTURE_RDR_MASK_2;
2081
2082 // Complain unless both the old and the new protection is in place.
2083 rcutorture_one_extend_check("during change", idxold1 | statesnew, statesnew, statesold);
2084
2085 // Sample CPU under both sets of protections to reduce confusion.
2086 if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)) {
2087 int cpu = raw_smp_processor_id();
2088 rtrsp->rt_cpu = cpu;
2089 if (!first) {
2090 rtrsp[-1].rt_end_cpu = cpu;
2091 if (cur_ops->reader_blocked)
2092 rtrsp[-1].rt_preempted = cur_ops->reader_blocked();
2093 }
2094 }
2095 // Sample grace-period sequence number, as good a place as any.
2096 if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_GP) && cur_ops->gather_gp_seqs) {
2097 rtrsp->rt_gp_seq = cur_ops->gather_gp_seqs();
2098 rtrsp->rt_ts = ktime_get_mono_fast_ns();
2099 if (!first)
2100 rtrsp[-1].rt_gp_seq_end = rtrsp->rt_gp_seq;
2101 }
2102
2103 /*
2104 * Next, remove old protection, in decreasing order of strength
2105 * to avoid unlock paths that aren't safe in the stronger
2106 * context. Namely: BH can not be enabled with disabled interrupts.
2107 * Additionally PREEMPT_RT requires that BH is enabled in preemptible
2108 * context.
2109 */
2110 if (statesold & RCUTORTURE_RDR_IRQ)
2111 local_irq_enable();
2112 if (statesold & RCUTORTURE_RDR_PREEMPT)
2113 preempt_enable();
2114 if (statesold & RCUTORTURE_RDR_SCHED)
2115 rcu_read_unlock_sched();
2116 if (statesold & RCUTORTURE_RDR_BH)
2117 local_bh_enable();
2118 if (statesold & RCUTORTURE_RDR_RBH)
2119 rcu_read_unlock_bh();
2120 if (statesold & RCUTORTURE_RDR_RCU_2) {
2121 cur_ops->readunlock((idxold2 & RCUTORTURE_RDR_MASK_2) >> RCUTORTURE_RDR_SHIFT_2);
2122 WARN_ON_ONCE(idxnew2 != -1);
2123 idxold2 = 0;
2124 }
2125 if (statesold & RCUTORTURE_RDR_RCU_1) {
2126 bool lockit;
2127
2128 lockit = !cur_ops->no_pi_lock && !statesnew && !(torture_random(trsp) & 0xffff);
2129 if (lockit)
2130 raw_spin_lock_irqsave(¤t->pi_lock, flags);
2131 cur_ops->readunlock((idxold1 & RCUTORTURE_RDR_MASK_1) >> RCUTORTURE_RDR_SHIFT_1);
2132 WARN_ON_ONCE(idxnew1 != -1);
2133 idxold1 = 0;
2134 if (lockit)
2135 raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
2136 }
2137 if (statesold & RCUTORTURE_RDR_UPDOWN) {
2138 cur_ops->up_read((idxold1 & RCUTORTURE_RDR_MASK_1) >> RCUTORTURE_RDR_SHIFT_1);
2139 WARN_ON_ONCE(idxnew1 != -1);
2140 idxold1 = 0;
2141 }
2142
2143 /* Delay if neither beginning nor end and there was a change. */
2144 if ((statesnew || statesold) && *readstate && newstate)
2145 cur_ops->read_delay(trsp, rtrsp);
2146
2147 /* Update the reader state. */
2148 if (idxnew1 == -1)
2149 idxnew1 = idxold1 & RCUTORTURE_RDR_MASK_1;
2150 WARN_ON_ONCE(idxnew1 < 0);
2151 if (idxnew2 == -1)
2152 idxnew2 = idxold2 & RCUTORTURE_RDR_MASK_2;
2153 WARN_ON_ONCE(idxnew2 < 0);
2154 *readstate = idxnew1 | idxnew2 | newstate;
2155 WARN_ON_ONCE(*readstate < 0);
2156 if (WARN_ON_ONCE(*readstate & ~RCUTORTURE_RDR_ALLBITS))
2157 pr_info("Unexpected readstate value of %#x\n", *readstate);
2158 rcutorture_one_extend_check("after change", *readstate, statesnew, statesold);
2159 }
2160
2161 /* Return the biggest extendables mask given current RCU and boot parameters. */
rcutorture_extend_mask_max(void)2162 static int rcutorture_extend_mask_max(void)
2163 {
2164 int mask;
2165
2166 WARN_ON_ONCE(extendables & ~RCUTORTURE_MAX_EXTEND);
2167 mask = extendables & RCUTORTURE_MAX_EXTEND & cur_ops->extendables;
2168 mask = mask | RCUTORTURE_RDR_RCU_1 | RCUTORTURE_RDR_RCU_2;
2169 return mask;
2170 }
2171
2172 /* Return a random protection state mask, but with at least one bit set. */
2173 static int
rcutorture_extend_mask(int oldmask,struct torture_random_state * trsp)2174 rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
2175 {
2176 int mask = rcutorture_extend_mask_max();
2177 unsigned long randmask1 = torture_random(trsp);
2178 unsigned long randmask2 = randmask1 >> 3;
2179 unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
2180 unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
2181 unsigned long bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
2182
2183 WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT_1); // Can't have reader idx bits.
2184 /* Mostly only one bit (need preemption!), sometimes lots of bits. */
2185 if (!(randmask1 & 0x7))
2186 mask = mask & randmask2;
2187 else
2188 mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
2189
2190 // Can't have nested RCU reader without outer RCU reader.
2191 if (!(mask & RCUTORTURE_RDR_RCU_1) && (mask & RCUTORTURE_RDR_RCU_2)) {
2192 if (oldmask & RCUTORTURE_RDR_RCU_1)
2193 mask &= ~RCUTORTURE_RDR_RCU_2;
2194 else
2195 mask |= RCUTORTURE_RDR_RCU_1;
2196 }
2197
2198 /*
2199 * Can't enable bh w/irq disabled.
2200 */
2201 if (mask & RCUTORTURE_RDR_IRQ)
2202 mask |= oldmask & bhs;
2203
2204 /*
2205 * Ideally these sequences would be detected in debug builds
2206 * (regardless of RT), but until then don't stop testing
2207 * them on non-RT.
2208 */
2209 if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
2210 /* Can't modify BH in atomic context */
2211 if (oldmask & preempts_irq)
2212 mask &= ~bhs;
2213 if ((oldmask | mask) & preempts_irq)
2214 mask |= oldmask & bhs;
2215 }
2216
2217 return mask ?: RCUTORTURE_RDR_RCU_1;
2218 }
2219
2220 /*
2221 * Do a randomly selected number of extensions of an existing RCU read-side
2222 * critical section.
2223 */
2224 static struct rt_read_seg *
rcutorture_loop_extend(int * readstate,struct torture_random_state * trsp,struct rt_read_seg * rtrsp)2225 rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp, struct rt_read_seg *rtrsp)
2226 {
2227 int i;
2228 int j;
2229 int mask = rcutorture_extend_mask_max();
2230
2231 WARN_ON_ONCE(!*readstate); /* -Existing- RCU read-side critsect! */
2232 if (!((mask - 1) & mask))
2233 return rtrsp; /* Current RCU reader not extendable. */
2234 /* Bias towards larger numbers of loops. */
2235 i = torture_random(trsp);
2236 i = ((i | (i >> 3)) & RCUTORTURE_RDR_MAX_LOOPS) + 1;
2237 for (j = 0; j < i; j++) {
2238 mask = rcutorture_extend_mask(*readstate, trsp);
2239 WARN_ON_ONCE(mask & RCUTORTURE_RDR_UPDOWN);
2240 rcutorture_one_extend(readstate, mask, trsp, &rtrsp[j]);
2241 }
2242 return &rtrsp[j];
2243 }
2244
2245 struct rcu_torture_one_read_state {
2246 bool checkpolling;
2247 unsigned long cookie;
2248 struct rcu_gp_oldstate cookie_full;
2249 unsigned long started;
2250 struct rcu_torture *p;
2251 int readstate;
2252 struct rt_read_seg rtseg[RCUTORTURE_RDR_MAX_SEGS];
2253 struct rt_read_seg *rtrsp;
2254 unsigned long long ts;
2255 };
2256
init_rcu_torture_one_read_state(struct rcu_torture_one_read_state * rtorsp,struct torture_random_state * trsp)2257 static void init_rcu_torture_one_read_state(struct rcu_torture_one_read_state *rtorsp,
2258 struct torture_random_state *trsp)
2259 {
2260 memset(rtorsp, 0, sizeof(*rtorsp));
2261 rtorsp->checkpolling = !(torture_random(trsp) & 0xfff);
2262 rtorsp->rtrsp = &rtorsp->rtseg[0];
2263 }
2264
2265 /*
2266 * Set up the first segment of a series of overlapping read-side
2267 * critical sections. The caller must have actually initiated the
2268 * outermost read-side critical section.
2269 */
rcu_torture_one_read_start(struct rcu_torture_one_read_state * rtorsp,struct torture_random_state * trsp,long myid)2270 static bool rcu_torture_one_read_start(struct rcu_torture_one_read_state *rtorsp,
2271 struct torture_random_state *trsp, long myid)
2272 {
2273 if (rtorsp->checkpolling) {
2274 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2275 rtorsp->cookie = cur_ops->get_gp_state();
2276 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2277 cur_ops->get_gp_state_full(&rtorsp->cookie_full);
2278 }
2279 rtorsp->started = cur_ops->get_gp_seq();
2280 rtorsp->ts = rcu_trace_clock_local();
2281 rtorsp->p = rcu_dereference_check(rcu_torture_current,
2282 !cur_ops->readlock_held || cur_ops->readlock_held() ||
2283 (rtorsp->readstate & RCUTORTURE_RDR_UPDOWN));
2284 if (rtorsp->p == NULL) {
2285 /* Wait for rcu_torture_writer to get underway */
2286 rcutorture_one_extend(&rtorsp->readstate, 0, trsp, rtorsp->rtrsp);
2287 return false;
2288 }
2289 if (rtorsp->p->rtort_mbtest == 0)
2290 atomic_inc(&n_rcu_torture_mberror);
2291 rcu_torture_reader_do_mbchk(myid, rtorsp->p, trsp);
2292 return true;
2293 }
2294
2295 /*
2296 * Complete the last segment of a series of overlapping read-side
2297 * critical sections and check for errors.
2298 */
rcu_torture_one_read_end(struct rcu_torture_one_read_state * rtorsp,struct torture_random_state * trsp)2299 static void rcu_torture_one_read_end(struct rcu_torture_one_read_state *rtorsp,
2300 struct torture_random_state *trsp)
2301 {
2302 int i;
2303 unsigned long completed;
2304 int pipe_count;
2305 bool preempted = false;
2306 struct rt_read_seg *rtrsp1;
2307
2308 preempt_disable();
2309 pipe_count = READ_ONCE(rtorsp->p->rtort_pipe_count);
2310 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
2311 // Should not happen in a correct RCU implementation,
2312 // happens quite often for torture_type=busted.
2313 pipe_count = RCU_TORTURE_PIPE_LEN;
2314 }
2315 completed = cur_ops->get_gp_seq();
2316 if (pipe_count > 1) {
2317 do_trace_rcu_torture_read(cur_ops->name, &rtorsp->p->rtort_rcu,
2318 rtorsp->ts, rtorsp->started, completed);
2319 rcu_ftrace_dump(DUMP_ALL);
2320 }
2321 __this_cpu_inc(rcu_torture_count[pipe_count]);
2322 completed = rcutorture_seq_diff(completed, rtorsp->started);
2323 if (completed > RCU_TORTURE_PIPE_LEN) {
2324 /* Should not happen, but... */
2325 completed = RCU_TORTURE_PIPE_LEN;
2326 }
2327 __this_cpu_inc(rcu_torture_batch[completed]);
2328 preempt_enable();
2329 if (rtorsp->checkpolling) {
2330 if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
2331 WARN_ONCE(cur_ops->poll_gp_state(rtorsp->cookie),
2332 "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
2333 __func__,
2334 rcu_torture_writer_state_getname(),
2335 rcu_torture_writer_state,
2336 rtorsp->cookie, cur_ops->get_gp_state());
2337 if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
2338 WARN_ONCE(cur_ops->poll_gp_state_full(&rtorsp->cookie_full),
2339 "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
2340 __func__,
2341 rcu_torture_writer_state_getname(),
2342 rcu_torture_writer_state,
2343 cpumask_pr_args(cpu_online_mask));
2344 }
2345 if (cur_ops->reader_blocked)
2346 preempted = cur_ops->reader_blocked();
2347 rcutorture_one_extend(&rtorsp->readstate, 0, trsp, rtorsp->rtrsp);
2348 WARN_ON_ONCE(rtorsp->readstate);
2349 // This next splat is expected behavior if leakpointer, especially
2350 // for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.
2351 WARN_ON_ONCE(leakpointer && READ_ONCE(rtorsp->p->rtort_pipe_count) > 1);
2352
2353 /* If error or close call, record the sequence of reader protections. */
2354 if ((pipe_count > 1 || completed > 1) && !xchg(&err_segs_recorded, 1)) {
2355 i = 0;
2356 for (rtrsp1 = &rtorsp->rtseg[0]; rtrsp1 < rtorsp->rtrsp; rtrsp1++)
2357 err_segs[i++] = *rtrsp1;
2358 rt_read_nsegs = i;
2359 rt_read_preempted = preempted;
2360 }
2361 }
2362
2363 /*
2364 * Do one read-side critical section, returning false if there was
2365 * no data to read. Can be invoked both from process context and
2366 * from a timer handler.
2367 */
rcu_torture_one_read(struct torture_random_state * trsp,long myid)2368 static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
2369 {
2370 int newstate;
2371 struct rcu_torture_one_read_state rtors;
2372
2373 WARN_ON_ONCE(!rcu_is_watching());
2374 init_rcu_torture_one_read_state(&rtors, trsp);
2375 newstate = rcutorture_extend_mask(rtors.readstate, trsp);
2376 WARN_ON_ONCE(newstate & RCUTORTURE_RDR_UPDOWN);
2377 rcutorture_one_extend(&rtors.readstate, newstate, trsp, rtors.rtrsp++);
2378 if (!rcu_torture_one_read_start(&rtors, trsp, myid)) {
2379 rcutorture_one_extend(&rtors.readstate, 0, trsp, rtors.rtrsp);
2380 return false;
2381 }
2382 rtors.rtrsp = rcutorture_loop_extend(&rtors.readstate, trsp, rtors.rtrsp);
2383 rcu_torture_one_read_end(&rtors, trsp);
2384 return true;
2385 }
2386
2387 static DEFINE_TORTURE_RANDOM_PERCPU(rcu_torture_timer_rand);
2388
2389 /*
2390 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
2391 * incrementing the corresponding element of the pipeline array. The
2392 * counter in the element should never be greater than 1, otherwise, the
2393 * RCU implementation is broken.
2394 */
rcu_torture_timer(struct timer_list * unused)2395 static void rcu_torture_timer(struct timer_list *unused)
2396 {
2397 atomic_long_inc(&n_rcu_torture_timers);
2398 (void)rcu_torture_one_read(this_cpu_ptr(&rcu_torture_timer_rand), -1);
2399
2400 /* Test call_rcu() invocation from interrupt handler. */
2401 if (cur_ops->call) {
2402 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT);
2403
2404 if (rhp)
2405 cur_ops->call(rhp, rcu_torture_timer_cb);
2406 }
2407 }
2408
2409 /*
2410 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
2411 * incrementing the corresponding element of the pipeline array. The
2412 * counter in the element should never be greater than 1, otherwise, the
2413 * RCU implementation is broken.
2414 */
2415 static int
rcu_torture_reader(void * arg)2416 rcu_torture_reader(void *arg)
2417 {
2418 unsigned long lastsleep = jiffies;
2419 long myid = (long)arg;
2420 int mynumonline = myid;
2421 DEFINE_TORTURE_RANDOM(rand);
2422 struct timer_list t;
2423
2424 VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
2425 set_user_nice(current, MAX_NICE);
2426 if (irqreader && cur_ops->irq_capable)
2427 timer_setup_on_stack(&t, rcu_torture_timer, 0);
2428 tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick.
2429 do {
2430 if (irqreader && cur_ops->irq_capable) {
2431 if (!timer_pending(&t))
2432 mod_timer(&t, jiffies + 1);
2433 }
2434 if (!rcu_torture_one_read(&rand, myid) && !torture_must_stop())
2435 schedule_timeout_interruptible(HZ);
2436 if (time_after(jiffies, lastsleep) && !torture_must_stop()) {
2437 torture_hrtimeout_us(500, 1000, &rand);
2438 lastsleep = jiffies + 10;
2439 }
2440 while (torture_num_online_cpus() < mynumonline && !torture_must_stop())
2441 schedule_timeout_interruptible(HZ / 5);
2442 stutter_wait("rcu_torture_reader");
2443 } while (!torture_must_stop());
2444 if (irqreader && cur_ops->irq_capable) {
2445 timer_delete_sync(&t);
2446 timer_destroy_on_stack(&t);
2447 }
2448 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
2449 torture_kthread_stopping("rcu_torture_reader");
2450 return 0;
2451 }
2452
2453 struct rcu_torture_one_read_state_updown {
2454 struct hrtimer rtorsu_hrt;
2455 bool rtorsu_inuse;
2456 ktime_t rtorsu_kt;
2457 int rtorsu_cpu;
2458 unsigned long rtorsu_j;
2459 unsigned long rtorsu_ndowns;
2460 unsigned long rtorsu_nups;
2461 unsigned long rtorsu_nmigrates;
2462 struct torture_random_state rtorsu_trs;
2463 struct rcu_torture_one_read_state rtorsu_rtors;
2464 };
2465
2466 static struct rcu_torture_one_read_state_updown *updownreaders;
2467 static DEFINE_TORTURE_RANDOM(rcu_torture_updown_rand);
2468 static int rcu_torture_updown(void *arg);
2469
rcu_torture_updown_hrt(struct hrtimer * hrtp)2470 static enum hrtimer_restart rcu_torture_updown_hrt(struct hrtimer *hrtp)
2471 {
2472 int cpu = raw_smp_processor_id();
2473 struct rcu_torture_one_read_state_updown *rtorsup;
2474
2475 rtorsup = container_of(hrtp, struct rcu_torture_one_read_state_updown, rtorsu_hrt);
2476 rcu_torture_one_read_end(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs);
2477 WARN_ONCE(rtorsup->rtorsu_nups >= rtorsup->rtorsu_ndowns, "%s: Up without matching down #%zu.\n", __func__, rtorsup - updownreaders);
2478 WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1);
2479 WRITE_ONCE(rtorsup->rtorsu_nmigrates,
2480 rtorsup->rtorsu_nmigrates + (cpu != rtorsup->rtorsu_cpu));
2481 smp_store_release(&rtorsup->rtorsu_inuse, false);
2482 return HRTIMER_NORESTART;
2483 }
2484
rcu_torture_updown_init(void)2485 static int rcu_torture_updown_init(void)
2486 {
2487 int i;
2488 struct torture_random_state *rand = &rcu_torture_updown_rand;
2489 int ret;
2490
2491 if (n_up_down < 0)
2492 return 0;
2493 if (!srcu_torture_have_up_down()) {
2494 VERBOSE_TOROUT_STRING("rcu_torture_updown_init: Disabling up/down reader tests due to lack of primitives");
2495 return 0;
2496 }
2497 updownreaders = kcalloc(n_up_down, sizeof(*updownreaders), GFP_KERNEL);
2498 if (!updownreaders) {
2499 VERBOSE_TOROUT_STRING("rcu_torture_updown_init: Out of memory, disabling up/down reader tests");
2500 return -ENOMEM;
2501 }
2502 for (i = 0; i < n_up_down; i++) {
2503 init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors, rand);
2504 hrtimer_setup(&updownreaders[i].rtorsu_hrt, rcu_torture_updown_hrt, CLOCK_MONOTONIC,
2505 HRTIMER_MODE_REL | HRTIMER_MODE_HARD);
2506 torture_random_init(&updownreaders[i].rtorsu_trs);
2507 init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors,
2508 &updownreaders[i].rtorsu_trs);
2509 }
2510 ret = torture_create_kthread(rcu_torture_updown, rand, updown_task);
2511 if (ret) {
2512 kfree(updownreaders);
2513 updownreaders = NULL;
2514 }
2515 return ret;
2516 }
2517
rcu_torture_updown_cleanup(void)2518 static void rcu_torture_updown_cleanup(void)
2519 {
2520 struct rcu_torture_one_read_state_updown *rtorsup;
2521
2522 for (rtorsup = updownreaders; rtorsup < &updownreaders[n_up_down]; rtorsup++) {
2523 if (!smp_load_acquire(&rtorsup->rtorsu_inuse))
2524 continue;
2525 if (hrtimer_cancel(&rtorsup->rtorsu_hrt) || WARN_ON_ONCE(rtorsup->rtorsu_inuse)) {
2526 rcu_torture_one_read_end(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs);
2527 WARN_ONCE(rtorsup->rtorsu_nups >= rtorsup->rtorsu_ndowns, "%s: Up without matching down #%zu.\n", __func__, rtorsup - updownreaders);
2528 WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1);
2529 smp_store_release(&rtorsup->rtorsu_inuse, false);
2530 }
2531
2532 }
2533 kfree(updownreaders);
2534 updownreaders = NULL;
2535 }
2536
2537 // Do one reader for rcu_torture_updown().
rcu_torture_updown_one(struct rcu_torture_one_read_state_updown * rtorsup)2538 static void rcu_torture_updown_one(struct rcu_torture_one_read_state_updown *rtorsup)
2539 {
2540 int idx;
2541 int rawidx;
2542 ktime_t t;
2543
2544 init_rcu_torture_one_read_state(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs);
2545 rawidx = cur_ops->down_read();
2546 WRITE_ONCE(rtorsup->rtorsu_ndowns, rtorsup->rtorsu_ndowns + 1);
2547 idx = (rawidx << RCUTORTURE_RDR_SHIFT_1) & RCUTORTURE_RDR_MASK_1;
2548 rtorsup->rtorsu_rtors.readstate = idx | RCUTORTURE_RDR_UPDOWN;
2549 rtorsup->rtorsu_rtors.rtrsp++;
2550 rtorsup->rtorsu_cpu = raw_smp_processor_id();
2551 if (!rcu_torture_one_read_start(&rtorsup->rtorsu_rtors, &rtorsup->rtorsu_trs, -1)) {
2552 WARN_ONCE(rtorsup->rtorsu_nups >= rtorsup->rtorsu_ndowns, "%s: Up without matching down #%zu.\n", __func__, rtorsup - updownreaders);
2553 WRITE_ONCE(rtorsup->rtorsu_nups, rtorsup->rtorsu_nups + 1);
2554 schedule_timeout_idle(HZ);
2555 return;
2556 }
2557 smp_store_release(&rtorsup->rtorsu_inuse, true);
2558 t = torture_random(&rtorsup->rtorsu_trs) & 0xfffff; // One per million.
2559 if (t < 10 * 1000)
2560 t = 200 * 1000 * 1000;
2561 hrtimer_start(&rtorsup->rtorsu_hrt, t, HRTIMER_MODE_REL | HRTIMER_MODE_HARD);
2562 smp_mb(); // Sample jiffies after posting hrtimer.
2563 rtorsup->rtorsu_j = jiffies; // Not used by hrtimer handler.
2564 rtorsup->rtorsu_kt = t;
2565 }
2566
2567 /*
2568 * RCU torture up/down reader kthread, starting RCU readers in kthread
2569 * context and ending them in hrtimer handlers. Otherwise similar to
2570 * rcu_torture_reader().
2571 */
2572 static int
rcu_torture_updown(void * arg)2573 rcu_torture_updown(void *arg)
2574 {
2575 unsigned long j;
2576 struct rcu_torture_one_read_state_updown *rtorsup;
2577
2578 VERBOSE_TOROUT_STRING("rcu_torture_updown task started");
2579 do {
2580 for (rtorsup = updownreaders; rtorsup < &updownreaders[n_up_down]; rtorsup++) {
2581 if (torture_must_stop())
2582 break;
2583 j = smp_load_acquire(&jiffies); // Time before ->rtorsu_inuse.
2584 if (smp_load_acquire(&rtorsup->rtorsu_inuse)) {
2585 WARN_ONCE(time_after(j, rtorsup->rtorsu_j + 1 + HZ * 10),
2586 "hrtimer queued at jiffies %lu for %lld ns took %lu jiffies\n", rtorsup->rtorsu_j, rtorsup->rtorsu_kt, j - rtorsup->rtorsu_j);
2587 continue;
2588 }
2589 rcu_torture_updown_one(rtorsup);
2590 }
2591 torture_hrtimeout_ms(1, 1000, &rcu_torture_updown_rand);
2592 stutter_wait("rcu_torture_updown");
2593 } while (!torture_must_stop());
2594 rcu_torture_updown_cleanup();
2595 torture_kthread_stopping("rcu_torture_updown");
2596 return 0;
2597 }
2598
2599 /*
2600 * Randomly Toggle CPUs' callback-offload state. This uses hrtimers to
2601 * increase race probabilities and fuzzes the interval between toggling.
2602 */
rcu_nocb_toggle(void * arg)2603 static int rcu_nocb_toggle(void *arg)
2604 {
2605 int cpu;
2606 int maxcpu = -1;
2607 int oldnice = task_nice(current);
2608 long r;
2609 DEFINE_TORTURE_RANDOM(rand);
2610 ktime_t toggle_delay;
2611 unsigned long toggle_fuzz;
2612 ktime_t toggle_interval = ms_to_ktime(nocbs_toggle);
2613
2614 VERBOSE_TOROUT_STRING("rcu_nocb_toggle task started");
2615 while (!rcu_inkernel_boot_has_ended())
2616 schedule_timeout_interruptible(HZ / 10);
2617 for_each_possible_cpu(cpu)
2618 maxcpu = cpu;
2619 WARN_ON(maxcpu < 0);
2620 if (toggle_interval > ULONG_MAX)
2621 toggle_fuzz = ULONG_MAX >> 3;
2622 else
2623 toggle_fuzz = toggle_interval >> 3;
2624 if (toggle_fuzz <= 0)
2625 toggle_fuzz = NSEC_PER_USEC;
2626 do {
2627 r = torture_random(&rand);
2628 cpu = (r >> 1) % (maxcpu + 1);
2629 if (r & 0x1) {
2630 rcu_nocb_cpu_offload(cpu);
2631 atomic_long_inc(&n_nocb_offload);
2632 } else {
2633 rcu_nocb_cpu_deoffload(cpu);
2634 atomic_long_inc(&n_nocb_deoffload);
2635 }
2636 toggle_delay = torture_random(&rand) % toggle_fuzz + toggle_interval;
2637 set_current_state(TASK_INTERRUPTIBLE);
2638 schedule_hrtimeout(&toggle_delay, HRTIMER_MODE_REL);
2639 if (stutter_wait("rcu_nocb_toggle"))
2640 sched_set_normal(current, oldnice);
2641 } while (!torture_must_stop());
2642 torture_kthread_stopping("rcu_nocb_toggle");
2643 return 0;
2644 }
2645
2646 /*
2647 * Print torture statistics. Caller must ensure that there is only
2648 * one call to this function at a given time!!! This is normally
2649 * accomplished by relying on the module system to only have one copy
2650 * of the module loaded, and then by giving the rcu_torture_stats
2651 * kthread full control (or the init/cleanup functions when rcu_torture_stats
2652 * thread is not running).
2653 */
2654 static void
rcu_torture_stats_print(void)2655 rcu_torture_stats_print(void)
2656 {
2657 int cpu;
2658 int i;
2659 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2660 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
2661 long n_gpwraps = 0;
2662 unsigned long ndowns = 0;
2663 unsigned long nunexpired = 0;
2664 unsigned long nmigrates = 0;
2665 unsigned long nups = 0;
2666 struct rcu_torture *rtcp;
2667 static unsigned long rtcv_snap = ULONG_MAX;
2668 static bool splatted;
2669 struct task_struct *wtp;
2670
2671 for_each_possible_cpu(cpu) {
2672 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2673 pipesummary[i] += READ_ONCE(per_cpu(rcu_torture_count, cpu)[i]);
2674 batchsummary[i] += READ_ONCE(per_cpu(rcu_torture_batch, cpu)[i]);
2675 }
2676 if (cur_ops->get_gpwrap_count)
2677 n_gpwraps += cur_ops->get_gpwrap_count(cpu);
2678 }
2679 if (updownreaders) {
2680 for (i = 0; i < n_up_down; i++) {
2681 ndowns += READ_ONCE(updownreaders[i].rtorsu_ndowns);
2682 nups += READ_ONCE(updownreaders[i].rtorsu_nups);
2683 nunexpired += READ_ONCE(updownreaders[i].rtorsu_inuse);
2684 nmigrates += READ_ONCE(updownreaders[i].rtorsu_nmigrates);
2685 }
2686 }
2687 for (i = RCU_TORTURE_PIPE_LEN; i >= 0; i--) {
2688 if (pipesummary[i] != 0)
2689 break;
2690 } // The value of variable "i" is used later, so don't clobber it!
2691
2692 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2693 rtcp = rcu_access_pointer(rcu_torture_current);
2694 pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
2695 rtcp,
2696 rtcp && !rcu_stall_is_suppressed_at_boot() ? "ver" : "VER",
2697 rcu_torture_current_version,
2698 list_empty(&rcu_torture_freelist),
2699 atomic_read(&n_rcu_torture_alloc),
2700 atomic_read(&n_rcu_torture_alloc_fail),
2701 atomic_read(&n_rcu_torture_free));
2702 pr_cont("rtmbe: %d rtmbkf: %d/%d rtbe: %ld rtbke: %ld ",
2703 atomic_read(&n_rcu_torture_mberror),
2704 atomic_read(&n_rcu_torture_mbchk_fail), atomic_read(&n_rcu_torture_mbchk_tries),
2705 n_rcu_torture_barrier_error,
2706 n_rcu_torture_boost_ktrerror);
2707 pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
2708 n_rcu_torture_boost_failure,
2709 n_rcu_torture_boosts,
2710 atomic_long_read(&n_rcu_torture_timers));
2711 if (updownreaders)
2712 pr_cont("ndowns: %lu nups: %lu nhrt: %lu nmigrates: %lu ", ndowns, nups, nunexpired, nmigrates);
2713 torture_onoff_stats();
2714 pr_cont("barrier: %ld/%ld:%ld ",
2715 data_race(n_barrier_successes),
2716 data_race(n_barrier_attempts),
2717 data_race(n_rcu_torture_barrier_error));
2718 pr_cont("read-exits: %ld ", data_race(n_read_exits)); // Statistic.
2719 pr_cont("nocb-toggles: %ld:%ld ",
2720 atomic_long_read(&n_nocb_offload), atomic_long_read(&n_nocb_deoffload));
2721 pr_cont("gpwraps: %ld\n", n_gpwraps);
2722
2723 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2724 if (atomic_read(&n_rcu_torture_mberror) ||
2725 atomic_read(&n_rcu_torture_mbchk_fail) ||
2726 n_rcu_torture_barrier_error || n_rcu_torture_boost_ktrerror ||
2727 n_rcu_torture_boost_failure || i > 1) {
2728 pr_cont("%s", "!!! ");
2729 atomic_inc(&n_rcu_torture_error);
2730 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mberror));
2731 WARN_ON_ONCE(atomic_read(&n_rcu_torture_mbchk_fail));
2732 WARN_ON_ONCE(n_rcu_torture_barrier_error); // rcu_barrier()
2733 WARN_ON_ONCE(n_rcu_torture_boost_ktrerror); // no boost kthread
2734 WARN_ON_ONCE(n_rcu_torture_boost_failure); // boost failed (TIMER_SOFTIRQ RT prio?)
2735 WARN_ON_ONCE(i > 1); // Too-short grace period
2736 }
2737 pr_cont("Reader Pipe: ");
2738 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2739 pr_cont(" %ld", pipesummary[i]);
2740 pr_cont("\n");
2741
2742 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2743 pr_cont("Reader Batch: ");
2744 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
2745 pr_cont(" %ld", batchsummary[i]);
2746 pr_cont("\n");
2747
2748 pr_alert("%s%s ", torture_type, TORTURE_FLAG);
2749 pr_cont("Free-Block Circulation: ");
2750 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
2751 pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
2752 }
2753 pr_cont("\n");
2754
2755 if (cur_ops->stats)
2756 cur_ops->stats();
2757 if (rtcv_snap == rcu_torture_current_version &&
2758 rcu_access_pointer(rcu_torture_current) &&
2759 !rcu_stall_is_suppressed()) {
2760 int __maybe_unused flags = 0;
2761 unsigned long __maybe_unused gp_seq = 0;
2762
2763 if (cur_ops->get_gp_data)
2764 cur_ops->get_gp_data(&flags, &gp_seq);
2765 wtp = READ_ONCE(writer_task);
2766 pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
2767 rcu_torture_writer_state_getname(),
2768 rcu_torture_writer_state, gp_seq, flags,
2769 wtp == NULL ? ~0U : wtp->__state,
2770 wtp == NULL ? -1 : (int)task_cpu(wtp));
2771 if (!splatted && wtp) {
2772 sched_show_task(wtp);
2773 splatted = true;
2774 }
2775 if (cur_ops->gp_kthread_dbg)
2776 cur_ops->gp_kthread_dbg();
2777 rcu_ftrace_dump(DUMP_ALL);
2778 }
2779 rtcv_snap = rcu_torture_current_version;
2780 }
2781
2782 /*
2783 * Periodically prints torture statistics, if periodic statistics printing
2784 * was specified via the stat_interval module parameter.
2785 */
2786 static int
rcu_torture_stats(void * arg)2787 rcu_torture_stats(void *arg)
2788 {
2789 VERBOSE_TOROUT_STRING("rcu_torture_stats task started");
2790 do {
2791 schedule_timeout_interruptible(stat_interval * HZ);
2792 rcu_torture_stats_print();
2793 torture_shutdown_absorb("rcu_torture_stats");
2794 } while (!torture_must_stop());
2795 torture_kthread_stopping("rcu_torture_stats");
2796 return 0;
2797 }
2798
2799 /* Test mem_dump_obj() and friends. */
rcu_torture_mem_dump_obj(void)2800 static void rcu_torture_mem_dump_obj(void)
2801 {
2802 struct rcu_head *rhp;
2803 struct kmem_cache *kcp;
2804 static int z;
2805
2806 kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
2807 if (WARN_ON_ONCE(!kcp))
2808 return;
2809 rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
2810 if (WARN_ON_ONCE(!rhp)) {
2811 kmem_cache_destroy(kcp);
2812 return;
2813 }
2814 pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
2815 pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
2816 mem_dump_obj(ZERO_SIZE_PTR);
2817 pr_alert("mem_dump_obj(NULL):");
2818 mem_dump_obj(NULL);
2819 pr_alert("mem_dump_obj(%px):", &rhp);
2820 mem_dump_obj(&rhp);
2821 pr_alert("mem_dump_obj(%px):", rhp);
2822 mem_dump_obj(rhp);
2823 pr_alert("mem_dump_obj(%px):", &rhp->func);
2824 mem_dump_obj(&rhp->func);
2825 pr_alert("mem_dump_obj(%px):", &z);
2826 mem_dump_obj(&z);
2827 kmem_cache_free(kcp, rhp);
2828 kmem_cache_destroy(kcp);
2829 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
2830 if (WARN_ON_ONCE(!rhp))
2831 return;
2832 pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2833 pr_alert("mem_dump_obj(kmalloc %px):", rhp);
2834 mem_dump_obj(rhp);
2835 pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
2836 mem_dump_obj(&rhp->func);
2837 kfree(rhp);
2838 rhp = vmalloc(4096);
2839 if (WARN_ON_ONCE(!rhp))
2840 return;
2841 pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
2842 pr_alert("mem_dump_obj(vmalloc %px):", rhp);
2843 mem_dump_obj(rhp);
2844 pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
2845 mem_dump_obj(&rhp->func);
2846 vfree(rhp);
2847 }
2848
2849 static void
rcu_torture_print_module_parms(struct rcu_torture_ops * cur_ops,const char * tag)2850 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
2851 {
2852 pr_alert("%s" TORTURE_FLAG
2853 "--- %s: nreaders=%d nfakewriters=%d "
2854 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
2855 "shuffle_interval=%d stutter=%d irqreader=%d "
2856 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
2857 "test_boost=%d/%d test_boost_interval=%d "
2858 "test_boost_duration=%d test_boost_holdoff=%d shutdown_secs=%d "
2859 "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
2860 "stall_cpu_block=%d stall_cpu_repeat=%d "
2861 "n_barrier_cbs=%d "
2862 "onoff_interval=%d onoff_holdoff=%d "
2863 "read_exit_delay=%d read_exit_burst=%d "
2864 "reader_flavor=%x "
2865 "nocbs_nthreads=%d nocbs_toggle=%d "
2866 "test_nmis=%d "
2867 "preempt_duration=%d preempt_interval=%d n_up_down=%d\n",
2868 torture_type, tag, nrealreaders, nrealfakewriters,
2869 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
2870 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
2871 test_boost, cur_ops->can_boost,
2872 test_boost_interval, test_boost_duration, test_boost_holdoff, shutdown_secs,
2873 stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
2874 stall_cpu_block, stall_cpu_repeat,
2875 n_barrier_cbs,
2876 onoff_interval, onoff_holdoff,
2877 read_exit_delay, read_exit_burst,
2878 reader_flavor,
2879 nocbs_nthreads, nocbs_toggle,
2880 test_nmis,
2881 preempt_duration, preempt_interval, n_up_down);
2882 }
2883
rcutorture_booster_cleanup(unsigned int cpu)2884 static int rcutorture_booster_cleanup(unsigned int cpu)
2885 {
2886 struct task_struct *t;
2887
2888 if (boost_tasks[cpu] == NULL)
2889 return 0;
2890 mutex_lock(&boost_mutex);
2891 t = boost_tasks[cpu];
2892 boost_tasks[cpu] = NULL;
2893 rcu_torture_enable_rt_throttle();
2894 mutex_unlock(&boost_mutex);
2895
2896 /* This must be outside of the mutex, otherwise deadlock! */
2897 torture_stop_kthread(rcu_torture_boost, t);
2898 return 0;
2899 }
2900
rcutorture_booster_init(unsigned int cpu)2901 static int rcutorture_booster_init(unsigned int cpu)
2902 {
2903 int retval;
2904
2905 if (boost_tasks[cpu] != NULL)
2906 return 0; /* Already created, nothing more to do. */
2907
2908 // Testing RCU priority boosting requires rcutorture do
2909 // some serious abuse. Counter this by running ksoftirqd
2910 // at higher priority.
2911 if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
2912 struct sched_param sp;
2913 struct task_struct *t;
2914
2915 t = per_cpu(ksoftirqd, cpu);
2916 WARN_ON_ONCE(!t);
2917 sp.sched_priority = 2;
2918 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2919 #ifdef CONFIG_IRQ_FORCED_THREADING
2920 if (force_irqthreads()) {
2921 t = per_cpu(ktimerd, cpu);
2922 WARN_ON_ONCE(!t);
2923 sp.sched_priority = 2;
2924 sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
2925 }
2926 #endif
2927 }
2928
2929 /* Don't allow time recalculation while creating a new task. */
2930 mutex_lock(&boost_mutex);
2931 rcu_torture_disable_rt_throttle();
2932 VERBOSE_TOROUT_STRING("Creating rcu_torture_boost task");
2933 boost_tasks[cpu] = kthread_run_on_cpu(rcu_torture_boost, NULL,
2934 cpu, "rcu_torture_boost_%u");
2935 if (IS_ERR(boost_tasks[cpu])) {
2936 retval = PTR_ERR(boost_tasks[cpu]);
2937 VERBOSE_TOROUT_STRING("rcu_torture_boost task create failed");
2938 n_rcu_torture_boost_ktrerror++;
2939 boost_tasks[cpu] = NULL;
2940 mutex_unlock(&boost_mutex);
2941 return retval;
2942 }
2943 mutex_unlock(&boost_mutex);
2944 return 0;
2945 }
2946
rcu_torture_stall_nf(struct notifier_block * nb,unsigned long v,void * ptr)2947 static int rcu_torture_stall_nf(struct notifier_block *nb, unsigned long v, void *ptr)
2948 {
2949 pr_info("%s: v=%lu, duration=%lu.\n", __func__, v, (unsigned long)ptr);
2950 return NOTIFY_OK;
2951 }
2952
2953 static struct notifier_block rcu_torture_stall_block = {
2954 .notifier_call = rcu_torture_stall_nf,
2955 };
2956
2957 /*
2958 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
2959 * induces a CPU stall for the time specified by stall_cpu. If a new
2960 * stall test is added, stallsdone in rcu_torture_writer() must be adjusted.
2961 */
rcu_torture_stall_one(int rep,int irqsoff)2962 static void rcu_torture_stall_one(int rep, int irqsoff)
2963 {
2964 int idx;
2965 unsigned long stop_at;
2966
2967 if (stall_cpu_holdoff > 0) {
2968 VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
2969 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
2970 VERBOSE_TOROUT_STRING("rcu_torture_stall end holdoff");
2971 }
2972 if (!kthread_should_stop() && stall_gp_kthread > 0) {
2973 VERBOSE_TOROUT_STRING("rcu_torture_stall begin GP stall");
2974 rcu_gp_set_torture_wait(stall_gp_kthread * HZ);
2975 for (idx = 0; idx < stall_gp_kthread + 2; idx++) {
2976 if (kthread_should_stop())
2977 break;
2978 schedule_timeout_uninterruptible(HZ);
2979 }
2980 }
2981 if (!kthread_should_stop() && stall_cpu > 0) {
2982 VERBOSE_TOROUT_STRING("rcu_torture_stall begin CPU stall");
2983 stop_at = ktime_get_seconds() + stall_cpu;
2984 /* RCU CPU stall is expected behavior in following code. */
2985 idx = cur_ops->readlock();
2986 if (irqsoff)
2987 local_irq_disable();
2988 else if (!stall_cpu_block)
2989 preempt_disable();
2990 pr_alert("%s start stall episode %d on CPU %d.\n",
2991 __func__, rep + 1, raw_smp_processor_id());
2992 while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(), stop_at) &&
2993 !kthread_should_stop())
2994 if (stall_cpu_block) {
2995 #ifdef CONFIG_PREEMPTION
2996 preempt_schedule();
2997 #else
2998 schedule_timeout_uninterruptible(HZ);
2999 #endif
3000 } else if (stall_no_softlockup) {
3001 touch_softlockup_watchdog();
3002 }
3003 if (irqsoff)
3004 local_irq_enable();
3005 else if (!stall_cpu_block)
3006 preempt_enable();
3007 cur_ops->readunlock(idx);
3008 }
3009 }
3010
3011 /*
3012 * CPU-stall kthread. Invokes rcu_torture_stall_one() once, and then as many
3013 * additional times as specified by the stall_cpu_repeat module parameter.
3014 * Note that stall_cpu_irqsoff is ignored on the second and subsequent
3015 * stall.
3016 */
rcu_torture_stall(void * args)3017 static int rcu_torture_stall(void *args)
3018 {
3019 int i;
3020 int repeat = stall_cpu_repeat;
3021 int ret;
3022
3023 VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
3024 if (repeat < 0) {
3025 repeat = 0;
3026 WARN_ON_ONCE(IS_BUILTIN(CONFIG_RCU_TORTURE_TEST));
3027 }
3028 if (rcu_cpu_stall_notifiers) {
3029 ret = rcu_stall_chain_notifier_register(&rcu_torture_stall_block);
3030 if (ret)
3031 pr_info("%s: rcu_stall_chain_notifier_register() returned %d, %sexpected.\n",
3032 __func__, ret, !IS_ENABLED(CONFIG_RCU_STALL_COMMON) ? "un" : "");
3033 }
3034 for (i = 0; i <= repeat; i++) {
3035 if (kthread_should_stop())
3036 break;
3037 rcu_torture_stall_one(i, i == 0 ? stall_cpu_irqsoff : 0);
3038 }
3039 pr_alert("%s end.\n", __func__);
3040 if (rcu_cpu_stall_notifiers && !ret) {
3041 ret = rcu_stall_chain_notifier_unregister(&rcu_torture_stall_block);
3042 if (ret)
3043 pr_info("%s: rcu_stall_chain_notifier_unregister() returned %d.\n", __func__, ret);
3044 }
3045 torture_shutdown_absorb("rcu_torture_stall");
3046 while (!kthread_should_stop())
3047 schedule_timeout_interruptible(10 * HZ);
3048 return 0;
3049 }
3050
3051 /* Spawn CPU-stall kthread, if stall_cpu specified. */
rcu_torture_stall_init(void)3052 static int __init rcu_torture_stall_init(void)
3053 {
3054 if (stall_cpu <= 0 && stall_gp_kthread <= 0)
3055 return 0;
3056 return torture_create_kthread(rcu_torture_stall, NULL, stall_task);
3057 }
3058
3059 /* State structure for forward-progress self-propagating RCU callback. */
3060 struct fwd_cb_state {
3061 struct rcu_head rh;
3062 int stop;
3063 };
3064
3065 /*
3066 * Forward-progress self-propagating RCU callback function. Because
3067 * callbacks run from softirq, this function is an implicit RCU read-side
3068 * critical section.
3069 */
rcu_torture_fwd_prog_cb(struct rcu_head * rhp)3070 static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
3071 {
3072 struct fwd_cb_state *fcsp = container_of(rhp, struct fwd_cb_state, rh);
3073
3074 if (READ_ONCE(fcsp->stop)) {
3075 WRITE_ONCE(fcsp->stop, 2);
3076 return;
3077 }
3078 cur_ops->call(&fcsp->rh, rcu_torture_fwd_prog_cb);
3079 }
3080
3081 /* State for continuous-flood RCU callbacks. */
3082 struct rcu_fwd_cb {
3083 struct rcu_head rh;
3084 struct rcu_fwd_cb *rfc_next;
3085 struct rcu_fwd *rfc_rfp;
3086 int rfc_gps;
3087 };
3088
3089 #define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
3090 #define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
3091 #define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
3092 #define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
3093 #define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
3094
3095 struct rcu_launder_hist {
3096 long n_launders;
3097 unsigned long launder_gp_seq;
3098 };
3099
3100 struct rcu_fwd {
3101 spinlock_t rcu_fwd_lock;
3102 struct rcu_fwd_cb *rcu_fwd_cb_head;
3103 struct rcu_fwd_cb **rcu_fwd_cb_tail;
3104 long n_launders_cb;
3105 unsigned long rcu_fwd_startat;
3106 struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
3107 unsigned long rcu_launder_gp_seq_start;
3108 int rcu_fwd_id;
3109 };
3110
3111 static DEFINE_MUTEX(rcu_fwd_mutex);
3112 static struct rcu_fwd *rcu_fwds;
3113 static unsigned long rcu_fwd_seq;
3114 static atomic_long_t rcu_fwd_max_cbs;
3115 static bool rcu_fwd_emergency_stop;
3116
rcu_torture_fwd_cb_hist(struct rcu_fwd * rfp)3117 static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
3118 {
3119 unsigned long gps;
3120 unsigned long gps_old;
3121 int i;
3122 int j;
3123
3124 for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
3125 if (rfp->n_launders_hist[i].n_launders > 0)
3126 break;
3127 pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
3128 __func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
3129 gps_old = rfp->rcu_launder_gp_seq_start;
3130 for (j = 0; j <= i; j++) {
3131 gps = rfp->n_launders_hist[j].launder_gp_seq;
3132 pr_cont(" %ds/%d: %ld:%ld",
3133 j + 1, FWD_CBS_HIST_DIV,
3134 rfp->n_launders_hist[j].n_launders,
3135 rcutorture_seq_diff(gps, gps_old));
3136 gps_old = gps;
3137 }
3138 pr_cont("\n");
3139 }
3140
3141 /* Callback function for continuous-flood RCU callbacks. */
rcu_torture_fwd_cb_cr(struct rcu_head * rhp)3142 static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
3143 {
3144 unsigned long flags;
3145 int i;
3146 struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
3147 struct rcu_fwd_cb **rfcpp;
3148 struct rcu_fwd *rfp = rfcp->rfc_rfp;
3149
3150 rfcp->rfc_next = NULL;
3151 rfcp->rfc_gps++;
3152 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
3153 rfcpp = rfp->rcu_fwd_cb_tail;
3154 rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
3155 smp_store_release(rfcpp, rfcp);
3156 WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
3157 i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
3158 if (i >= ARRAY_SIZE(rfp->n_launders_hist))
3159 i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
3160 rfp->n_launders_hist[i].n_launders++;
3161 rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
3162 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
3163 }
3164
3165 // Give the scheduler a chance, even on nohz_full CPUs.
rcu_torture_fwd_prog_cond_resched(unsigned long iter)3166 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
3167 {
3168 if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
3169 // Real call_rcu() floods hit userspace, so emulate that.
3170 if (need_resched() || (iter & 0xfff))
3171 schedule();
3172 return;
3173 }
3174 // No userspace emulation: CB invocation throttles call_rcu()
3175 cond_resched();
3176 }
3177
3178 /*
3179 * Free all callbacks on the rcu_fwd_cb_head list, either because the
3180 * test is over or because we hit an OOM event.
3181 */
rcu_torture_fwd_prog_cbfree(struct rcu_fwd * rfp)3182 static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
3183 {
3184 unsigned long flags;
3185 unsigned long freed = 0;
3186 struct rcu_fwd_cb *rfcp;
3187
3188 for (;;) {
3189 spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
3190 rfcp = rfp->rcu_fwd_cb_head;
3191 if (!rfcp) {
3192 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
3193 break;
3194 }
3195 rfp->rcu_fwd_cb_head = rfcp->rfc_next;
3196 if (!rfp->rcu_fwd_cb_head)
3197 rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
3198 spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
3199 kfree(rfcp);
3200 freed++;
3201 rcu_torture_fwd_prog_cond_resched(freed);
3202 if (tick_nohz_full_enabled()) {
3203 local_irq_save(flags);
3204 rcu_momentary_eqs();
3205 local_irq_restore(flags);
3206 }
3207 }
3208 return freed;
3209 }
3210
3211 /* Carry out need_resched()/cond_resched() forward-progress testing. */
rcu_torture_fwd_prog_nr(struct rcu_fwd * rfp,int * tested,int * tested_tries)3212 static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
3213 int *tested, int *tested_tries)
3214 {
3215 unsigned long cver;
3216 unsigned long dur;
3217 struct fwd_cb_state fcs;
3218 unsigned long gps;
3219 int idx;
3220 int sd;
3221 int sd4;
3222 bool selfpropcb = false;
3223 unsigned long stopat;
3224 static DEFINE_TORTURE_RANDOM(trs);
3225
3226 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
3227 if (!cur_ops->sync)
3228 return; // Cannot do need_resched() forward progress testing without ->sync.
3229 if (cur_ops->call && cur_ops->cb_barrier) {
3230 init_rcu_head_on_stack(&fcs.rh);
3231 selfpropcb = true;
3232 }
3233
3234 /* Tight loop containing cond_resched(). */
3235 atomic_inc(&rcu_fwd_cb_nodelay);
3236 cur_ops->sync(); /* Later readers see above write. */
3237 if (selfpropcb) {
3238 WRITE_ONCE(fcs.stop, 0);
3239 cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
3240 }
3241 cver = READ_ONCE(rcu_torture_current_version);
3242 gps = cur_ops->get_gp_seq();
3243 sd = cur_ops->stall_dur() + 1;
3244 sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
3245 dur = sd4 + torture_random(&trs) % (sd - sd4);
3246 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
3247 stopat = rfp->rcu_fwd_startat + dur;
3248 while (time_before(jiffies, stopat) &&
3249 !shutdown_time_arrived() &&
3250 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
3251 idx = cur_ops->readlock();
3252 udelay(10);
3253 cur_ops->readunlock(idx);
3254 if (!fwd_progress_need_resched || need_resched())
3255 cond_resched();
3256 }
3257 (*tested_tries)++;
3258 if (!time_before(jiffies, stopat) &&
3259 !shutdown_time_arrived() &&
3260 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
3261 (*tested)++;
3262 cver = READ_ONCE(rcu_torture_current_version) - cver;
3263 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
3264 WARN_ON(!cver && gps < 2);
3265 pr_alert("%s: %d Duration %ld cver %ld gps %ld\n", __func__,
3266 rfp->rcu_fwd_id, dur, cver, gps);
3267 }
3268 if (selfpropcb) {
3269 WRITE_ONCE(fcs.stop, 1);
3270 cur_ops->sync(); /* Wait for running CB to complete. */
3271 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
3272 cur_ops->cb_barrier(); /* Wait for queued callbacks. */
3273 }
3274
3275 if (selfpropcb) {
3276 WARN_ON(READ_ONCE(fcs.stop) != 2);
3277 destroy_rcu_head_on_stack(&fcs.rh);
3278 }
3279 schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
3280 atomic_dec(&rcu_fwd_cb_nodelay);
3281 }
3282
3283 /* Carry out call_rcu() forward-progress testing. */
rcu_torture_fwd_prog_cr(struct rcu_fwd * rfp)3284 static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
3285 {
3286 unsigned long cver;
3287 unsigned long flags;
3288 unsigned long gps;
3289 int i;
3290 long n_launders;
3291 long n_launders_cb_snap;
3292 long n_launders_sa;
3293 long n_max_cbs;
3294 long n_max_gps;
3295 struct rcu_fwd_cb *rfcp;
3296 struct rcu_fwd_cb *rfcpn;
3297 unsigned long stopat;
3298 unsigned long stoppedat;
3299
3300 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
3301 if (READ_ONCE(rcu_fwd_emergency_stop))
3302 return; /* Get out of the way quickly, no GP wait! */
3303 if (!cur_ops->call)
3304 return; /* Can't do call_rcu() fwd prog without ->call. */
3305
3306 /* Loop continuously posting RCU callbacks. */
3307 atomic_inc(&rcu_fwd_cb_nodelay);
3308 cur_ops->sync(); /* Later readers see above write. */
3309 WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
3310 stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
3311 n_launders = 0;
3312 rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
3313 n_launders_sa = 0;
3314 n_max_cbs = 0;
3315 n_max_gps = 0;
3316 for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
3317 rfp->n_launders_hist[i].n_launders = 0;
3318 cver = READ_ONCE(rcu_torture_current_version);
3319 gps = cur_ops->get_gp_seq();
3320 rfp->rcu_launder_gp_seq_start = gps;
3321 tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick.
3322 while (time_before(jiffies, stopat) &&
3323 !shutdown_time_arrived() &&
3324 !READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
3325 rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
3326 rfcpn = NULL;
3327 if (rfcp)
3328 rfcpn = READ_ONCE(rfcp->rfc_next);
3329 if (rfcpn) {
3330 if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
3331 ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
3332 break;
3333 rfp->rcu_fwd_cb_head = rfcpn;
3334 n_launders++;
3335 n_launders_sa++;
3336 } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
3337 rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
3338 if (WARN_ON_ONCE(!rfcp)) {
3339 schedule_timeout_interruptible(1);
3340 continue;
3341 }
3342 n_max_cbs++;
3343 n_launders_sa = 0;
3344 rfcp->rfc_gps = 0;
3345 rfcp->rfc_rfp = rfp;
3346 } else {
3347 rfcp = NULL;
3348 }
3349 if (rfcp)
3350 cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
3351 rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
3352 if (tick_nohz_full_enabled()) {
3353 local_irq_save(flags);
3354 rcu_momentary_eqs();
3355 local_irq_restore(flags);
3356 }
3357 }
3358 stoppedat = jiffies;
3359 n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
3360 cver = READ_ONCE(rcu_torture_current_version) - cver;
3361 gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
3362 pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
3363 cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
3364 (void)rcu_torture_fwd_prog_cbfree(rfp);
3365
3366 if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
3367 !shutdown_time_arrived()) {
3368 if (WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED) && cur_ops->gp_kthread_dbg)
3369 cur_ops->gp_kthread_dbg();
3370 pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld #online %u\n",
3371 __func__,
3372 stoppedat - rfp->rcu_fwd_startat, jiffies - stoppedat,
3373 n_launders + n_max_cbs - n_launders_cb_snap,
3374 n_launders, n_launders_sa,
3375 n_max_gps, n_max_cbs, cver, gps, num_online_cpus());
3376 atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
3377 mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
3378 rcu_torture_fwd_cb_hist(rfp);
3379 mutex_unlock(&rcu_fwd_mutex);
3380 }
3381 schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
3382 tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
3383 atomic_dec(&rcu_fwd_cb_nodelay);
3384 }
3385
3386
3387 /*
3388 * OOM notifier, but this only prints diagnostic information for the
3389 * current forward-progress test.
3390 */
rcutorture_oom_notify(struct notifier_block * self,unsigned long notused,void * nfreed)3391 static int rcutorture_oom_notify(struct notifier_block *self,
3392 unsigned long notused, void *nfreed)
3393 {
3394 int i;
3395 long ncbs;
3396 struct rcu_fwd *rfp;
3397
3398 mutex_lock(&rcu_fwd_mutex);
3399 rfp = rcu_fwds;
3400 if (!rfp) {
3401 mutex_unlock(&rcu_fwd_mutex);
3402 return NOTIFY_OK;
3403 }
3404 WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
3405 __func__);
3406 for (i = 0; i < fwd_progress; i++) {
3407 rcu_torture_fwd_cb_hist(&rfp[i]);
3408 rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp[i].rcu_fwd_startat)) / 2);
3409 }
3410 WRITE_ONCE(rcu_fwd_emergency_stop, true);
3411 smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
3412 ncbs = 0;
3413 for (i = 0; i < fwd_progress; i++)
3414 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
3415 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
3416 cur_ops->cb_barrier();
3417 ncbs = 0;
3418 for (i = 0; i < fwd_progress; i++)
3419 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
3420 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
3421 cur_ops->cb_barrier();
3422 ncbs = 0;
3423 for (i = 0; i < fwd_progress; i++)
3424 ncbs += rcu_torture_fwd_prog_cbfree(&rfp[i]);
3425 pr_info("%s: Freed %lu RCU callbacks.\n", __func__, ncbs);
3426 smp_mb(); /* Frees before return to avoid redoing OOM. */
3427 (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
3428 pr_info("%s returning after OOM processing.\n", __func__);
3429 mutex_unlock(&rcu_fwd_mutex);
3430 return NOTIFY_OK;
3431 }
3432
3433 static struct notifier_block rcutorture_oom_nb = {
3434 .notifier_call = rcutorture_oom_notify
3435 };
3436
3437 /* Carry out grace-period forward-progress testing. */
rcu_torture_fwd_prog(void * args)3438 static int rcu_torture_fwd_prog(void *args)
3439 {
3440 bool firsttime = true;
3441 long max_cbs;
3442 int oldnice = task_nice(current);
3443 unsigned long oldseq = READ_ONCE(rcu_fwd_seq);
3444 struct rcu_fwd *rfp = args;
3445 int tested = 0;
3446 int tested_tries = 0;
3447
3448 VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
3449 rcu_bind_current_to_nocb();
3450 if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
3451 set_user_nice(current, MAX_NICE);
3452 do {
3453 if (!rfp->rcu_fwd_id) {
3454 schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
3455 WRITE_ONCE(rcu_fwd_emergency_stop, false);
3456 if (!firsttime) {
3457 max_cbs = atomic_long_xchg(&rcu_fwd_max_cbs, 0);
3458 pr_alert("%s n_max_cbs: %ld\n", __func__, max_cbs);
3459 }
3460 firsttime = false;
3461 WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
3462 } else {
3463 while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
3464 schedule_timeout_interruptible(HZ / 20);
3465 oldseq = READ_ONCE(rcu_fwd_seq);
3466 }
3467 pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
3468 if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
3469 rcu_torture_fwd_prog_cr(rfp);
3470 if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
3471 (!IS_ENABLED(CONFIG_TINY_RCU) ||
3472 (rcu_inkernel_boot_has_ended() &&
3473 torture_num_online_cpus() > rfp->rcu_fwd_id)))
3474 rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
3475
3476 /* Avoid slow periods, better to test when busy. */
3477 if (stutter_wait("rcu_torture_fwd_prog"))
3478 sched_set_normal(current, oldnice);
3479 } while (!torture_must_stop());
3480 /* Short runs might not contain a valid forward-progress attempt. */
3481 if (!rfp->rcu_fwd_id) {
3482 WARN_ON(!tested && tested_tries >= 5);
3483 pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);
3484 }
3485 torture_kthread_stopping("rcu_torture_fwd_prog");
3486 return 0;
3487 }
3488
3489 /* If forward-progress checking is requested and feasible, spawn the thread. */
rcu_torture_fwd_prog_init(void)3490 static int __init rcu_torture_fwd_prog_init(void)
3491 {
3492 int i;
3493 int ret = 0;
3494 struct rcu_fwd *rfp;
3495
3496 if (!fwd_progress)
3497 return 0; /* Not requested, so don't do it. */
3498 if (fwd_progress >= nr_cpu_ids) {
3499 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Limiting fwd_progress to # CPUs.\n");
3500 fwd_progress = nr_cpu_ids;
3501 } else if (fwd_progress < 0) {
3502 fwd_progress = nr_cpu_ids;
3503 }
3504 if ((!cur_ops->sync && !cur_ops->call) ||
3505 (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
3506 cur_ops == &rcu_busted_ops) {
3507 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
3508 fwd_progress = 0;
3509 return 0;
3510 }
3511 if (stall_cpu > 0 || (preempt_duration > 0 && IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
3512 VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, conflicts with CPU-stall and/or preemption testing");
3513 fwd_progress = 0;
3514 if (IS_MODULE(CONFIG_RCU_TORTURE_TEST))
3515 return -EINVAL; /* In module, can fail back to user. */
3516 WARN_ON(1); /* Make sure rcutorture scripting notices conflict. */
3517 return 0;
3518 }
3519 if (fwd_progress_holdoff <= 0)
3520 fwd_progress_holdoff = 1;
3521 if (fwd_progress_div <= 0)
3522 fwd_progress_div = 4;
3523 rfp = kcalloc(fwd_progress, sizeof(*rfp), GFP_KERNEL);
3524 fwd_prog_tasks = kcalloc(fwd_progress, sizeof(*fwd_prog_tasks), GFP_KERNEL);
3525 if (!rfp || !fwd_prog_tasks) {
3526 kfree(rfp);
3527 kfree(fwd_prog_tasks);
3528 fwd_prog_tasks = NULL;
3529 fwd_progress = 0;
3530 return -ENOMEM;
3531 }
3532 for (i = 0; i < fwd_progress; i++) {
3533 spin_lock_init(&rfp[i].rcu_fwd_lock);
3534 rfp[i].rcu_fwd_cb_tail = &rfp[i].rcu_fwd_cb_head;
3535 rfp[i].rcu_fwd_id = i;
3536 }
3537 mutex_lock(&rcu_fwd_mutex);
3538 rcu_fwds = rfp;
3539 mutex_unlock(&rcu_fwd_mutex);
3540 register_oom_notifier(&rcutorture_oom_nb);
3541 for (i = 0; i < fwd_progress; i++) {
3542 ret = torture_create_kthread(rcu_torture_fwd_prog, &rcu_fwds[i], fwd_prog_tasks[i]);
3543 if (ret) {
3544 fwd_progress = i;
3545 return ret;
3546 }
3547 }
3548 return 0;
3549 }
3550
rcu_torture_fwd_prog_cleanup(void)3551 static void rcu_torture_fwd_prog_cleanup(void)
3552 {
3553 int i;
3554 struct rcu_fwd *rfp;
3555
3556 if (!rcu_fwds || !fwd_prog_tasks)
3557 return;
3558 for (i = 0; i < fwd_progress; i++)
3559 torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_tasks[i]);
3560 unregister_oom_notifier(&rcutorture_oom_nb);
3561 mutex_lock(&rcu_fwd_mutex);
3562 rfp = rcu_fwds;
3563 rcu_fwds = NULL;
3564 mutex_unlock(&rcu_fwd_mutex);
3565 kfree(rfp);
3566 kfree(fwd_prog_tasks);
3567 fwd_prog_tasks = NULL;
3568 }
3569
3570 /* Callback function for RCU barrier testing. */
rcu_torture_barrier_cbf(struct rcu_head * rcu)3571 static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
3572 {
3573 atomic_inc(&barrier_cbs_invoked);
3574 }
3575
3576 /* IPI handler to get callback posted on desired CPU, if online. */
rcu_torture_barrier1cb(void * rcu_void)3577 static int rcu_torture_barrier1cb(void *rcu_void)
3578 {
3579 struct rcu_head *rhp = rcu_void;
3580
3581 cur_ops->call(rhp, rcu_torture_barrier_cbf);
3582 return 0;
3583 }
3584
3585 /* kthread function to register callbacks used to test RCU barriers. */
rcu_torture_barrier_cbs(void * arg)3586 static int rcu_torture_barrier_cbs(void *arg)
3587 {
3588 long myid = (long)arg;
3589 bool lastphase = false;
3590 bool newphase;
3591 struct rcu_head rcu;
3592
3593 init_rcu_head_on_stack(&rcu);
3594 VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task started");
3595 set_user_nice(current, MAX_NICE);
3596 do {
3597 wait_event(barrier_cbs_wq[myid],
3598 (newphase =
3599 smp_load_acquire(&barrier_phase)) != lastphase ||
3600 torture_must_stop());
3601 lastphase = newphase;
3602 if (torture_must_stop())
3603 break;
3604 /*
3605 * The above smp_load_acquire() ensures barrier_phase load
3606 * is ordered before the following ->call().
3607 */
3608 if (smp_call_on_cpu(myid, rcu_torture_barrier1cb, &rcu, 1))
3609 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
3610
3611 if (atomic_dec_and_test(&barrier_cbs_count))
3612 wake_up(&barrier_wq);
3613 } while (!torture_must_stop());
3614 if (cur_ops->cb_barrier != NULL)
3615 cur_ops->cb_barrier();
3616 destroy_rcu_head_on_stack(&rcu);
3617 torture_kthread_stopping("rcu_torture_barrier_cbs");
3618 return 0;
3619 }
3620
3621 /* kthread function to drive and coordinate RCU barrier testing. */
rcu_torture_barrier(void * arg)3622 static int rcu_torture_barrier(void *arg)
3623 {
3624 int i;
3625
3626 VERBOSE_TOROUT_STRING("rcu_torture_barrier task starting");
3627 do {
3628 atomic_set(&barrier_cbs_invoked, 0);
3629 atomic_set(&barrier_cbs_count, n_barrier_cbs);
3630 /* Ensure barrier_phase ordered after prior assignments. */
3631 smp_store_release(&barrier_phase, !barrier_phase);
3632 for (i = 0; i < n_barrier_cbs; i++)
3633 wake_up(&barrier_cbs_wq[i]);
3634 wait_event(barrier_wq,
3635 atomic_read(&barrier_cbs_count) == 0 ||
3636 torture_must_stop());
3637 if (torture_must_stop())
3638 break;
3639 n_barrier_attempts++;
3640 cur_ops->cb_barrier(); /* Implies smp_mb() for wait_event(). */
3641 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
3642 n_rcu_torture_barrier_error++;
3643 pr_err("barrier_cbs_invoked = %d, n_barrier_cbs = %d\n",
3644 atomic_read(&barrier_cbs_invoked),
3645 n_barrier_cbs);
3646 WARN_ON(1);
3647 // Wait manually for the remaining callbacks
3648 i = 0;
3649 do {
3650 if (WARN_ON(i++ > HZ))
3651 i = INT_MIN;
3652 schedule_timeout_interruptible(1);
3653 cur_ops->cb_barrier();
3654 } while (atomic_read(&barrier_cbs_invoked) !=
3655 n_barrier_cbs &&
3656 !torture_must_stop());
3657 smp_mb(); // Can't trust ordering if broken.
3658 if (!torture_must_stop())
3659 pr_err("Recovered: barrier_cbs_invoked = %d\n",
3660 atomic_read(&barrier_cbs_invoked));
3661 } else {
3662 n_barrier_successes++;
3663 }
3664 schedule_timeout_interruptible(HZ / 10);
3665 } while (!torture_must_stop());
3666 torture_kthread_stopping("rcu_torture_barrier");
3667 return 0;
3668 }
3669
3670 /* Initialize RCU barrier testing. */
rcu_torture_barrier_init(void)3671 static int rcu_torture_barrier_init(void)
3672 {
3673 int i;
3674 int ret;
3675
3676 if (n_barrier_cbs <= 0)
3677 return 0;
3678 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
3679 pr_alert("%s" TORTURE_FLAG
3680 " Call or barrier ops missing for %s,\n",
3681 torture_type, cur_ops->name);
3682 pr_alert("%s" TORTURE_FLAG
3683 " RCU barrier testing omitted from run.\n",
3684 torture_type);
3685 return 0;
3686 }
3687 atomic_set(&barrier_cbs_count, 0);
3688 atomic_set(&barrier_cbs_invoked, 0);
3689 barrier_cbs_tasks =
3690 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_tasks[0]),
3691 GFP_KERNEL);
3692 barrier_cbs_wq =
3693 kcalloc(n_barrier_cbs, sizeof(barrier_cbs_wq[0]), GFP_KERNEL);
3694 if (barrier_cbs_tasks == NULL || !barrier_cbs_wq)
3695 return -ENOMEM;
3696 for (i = 0; i < n_barrier_cbs; i++) {
3697 init_waitqueue_head(&barrier_cbs_wq[i]);
3698 ret = torture_create_kthread(rcu_torture_barrier_cbs,
3699 (void *)(long)i,
3700 barrier_cbs_tasks[i]);
3701 if (ret)
3702 return ret;
3703 }
3704 return torture_create_kthread(rcu_torture_barrier, NULL, barrier_task);
3705 }
3706
3707 /* Clean up after RCU barrier testing. */
rcu_torture_barrier_cleanup(void)3708 static void rcu_torture_barrier_cleanup(void)
3709 {
3710 int i;
3711
3712 torture_stop_kthread(rcu_torture_barrier, barrier_task);
3713 if (barrier_cbs_tasks != NULL) {
3714 for (i = 0; i < n_barrier_cbs; i++)
3715 torture_stop_kthread(rcu_torture_barrier_cbs,
3716 barrier_cbs_tasks[i]);
3717 kfree(barrier_cbs_tasks);
3718 barrier_cbs_tasks = NULL;
3719 }
3720 if (barrier_cbs_wq != NULL) {
3721 kfree(barrier_cbs_wq);
3722 barrier_cbs_wq = NULL;
3723 }
3724 }
3725
rcu_torture_can_boost(void)3726 static bool rcu_torture_can_boost(void)
3727 {
3728 static int boost_warn_once;
3729 int prio;
3730
3731 if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
3732 return false;
3733 if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
3734 return false;
3735
3736 prio = rcu_get_gp_kthreads_prio();
3737 if (!prio)
3738 return false;
3739
3740 if (prio < 2) {
3741 if (boost_warn_once == 1)
3742 return false;
3743
3744 pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
3745 boost_warn_once = 1;
3746 return false;
3747 }
3748
3749 return true;
3750 }
3751
3752 static bool read_exit_child_stop;
3753 static bool read_exit_child_stopped;
3754 static wait_queue_head_t read_exit_wq;
3755
3756 // Child kthread which just does an rcutorture reader and exits.
rcu_torture_read_exit_child(void * trsp_in)3757 static int rcu_torture_read_exit_child(void *trsp_in)
3758 {
3759 struct torture_random_state *trsp = trsp_in;
3760
3761 set_user_nice(current, MAX_NICE);
3762 // Minimize time between reading and exiting.
3763 while (!kthread_should_stop())
3764 schedule_timeout_uninterruptible(HZ / 20);
3765 (void)rcu_torture_one_read(trsp, -1);
3766 return 0;
3767 }
3768
3769 // Parent kthread which creates and destroys read-exit child kthreads.
rcu_torture_read_exit(void * unused)3770 static int rcu_torture_read_exit(void *unused)
3771 {
3772 bool errexit = false;
3773 int i;
3774 struct task_struct *tsp;
3775 DEFINE_TORTURE_RANDOM(trs);
3776
3777 // Allocate and initialize.
3778 set_user_nice(current, MAX_NICE);
3779 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
3780
3781 // Each pass through this loop does one read-exit episode.
3782 do {
3783 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
3784 for (i = 0; i < read_exit_burst; i++) {
3785 if (READ_ONCE(read_exit_child_stop))
3786 break;
3787 stutter_wait("rcu_torture_read_exit");
3788 // Spawn child.
3789 tsp = kthread_run(rcu_torture_read_exit_child,
3790 &trs, "%s", "rcu_torture_read_exit_child");
3791 if (IS_ERR(tsp)) {
3792 TOROUT_ERRSTRING("out of memory");
3793 errexit = true;
3794 break;
3795 }
3796 cond_resched();
3797 kthread_stop(tsp);
3798 n_read_exits++;
3799 }
3800 VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
3801 rcu_barrier(); // Wait for task_struct free, avoid OOM.
3802 i = 0;
3803 for (; !errexit && !READ_ONCE(read_exit_child_stop) && i < read_exit_delay; i++)
3804 schedule_timeout_uninterruptible(HZ);
3805 } while (!errexit && !READ_ONCE(read_exit_child_stop));
3806
3807 // Clean up and exit.
3808 smp_store_release(&read_exit_child_stopped, true); // After reaping.
3809 smp_mb(); // Store before wakeup.
3810 wake_up(&read_exit_wq);
3811 while (!torture_must_stop())
3812 schedule_timeout_uninterruptible(HZ / 20);
3813 torture_kthread_stopping("rcu_torture_read_exit");
3814 return 0;
3815 }
3816
rcu_torture_read_exit_init(void)3817 static int rcu_torture_read_exit_init(void)
3818 {
3819 if (read_exit_burst <= 0)
3820 return 0;
3821 init_waitqueue_head(&read_exit_wq);
3822 read_exit_child_stop = false;
3823 read_exit_child_stopped = false;
3824 return torture_create_kthread(rcu_torture_read_exit, NULL,
3825 read_exit_task);
3826 }
3827
rcu_torture_read_exit_cleanup(void)3828 static void rcu_torture_read_exit_cleanup(void)
3829 {
3830 if (!read_exit_task)
3831 return;
3832 WRITE_ONCE(read_exit_child_stop, true);
3833 smp_mb(); // Above write before wait.
3834 wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
3835 torture_stop_kthread(rcutorture_read_exit, read_exit_task);
3836 }
3837
rcutorture_test_nmis(int n)3838 static void rcutorture_test_nmis(int n)
3839 {
3840 #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3841 int cpu;
3842 int dumpcpu;
3843 int i;
3844
3845 for (i = 0; i < n; i++) {
3846 preempt_disable();
3847 cpu = smp_processor_id();
3848 dumpcpu = cpu + 1;
3849 if (dumpcpu >= nr_cpu_ids)
3850 dumpcpu = 0;
3851 pr_alert("%s: CPU %d invoking dump_cpu_task(%d)\n", __func__, cpu, dumpcpu);
3852 dump_cpu_task(dumpcpu);
3853 preempt_enable();
3854 schedule_timeout_uninterruptible(15 * HZ);
3855 }
3856 #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3857 WARN_ONCE(n, "Non-zero rcutorture.test_nmis=%d permitted only when rcutorture is built in.\n", test_nmis);
3858 #endif // #else // #if IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)
3859 }
3860
3861 // Randomly preempt online CPUs.
rcu_torture_preempt(void * unused)3862 static int rcu_torture_preempt(void *unused)
3863 {
3864 int cpu = -1;
3865 DEFINE_TORTURE_RANDOM(rand);
3866
3867 schedule_timeout_idle(stall_cpu_holdoff);
3868 do {
3869 // Wait for preempt_interval ms with up to 100us fuzz.
3870 torture_hrtimeout_ms(preempt_interval, 100, &rand);
3871 // Select online CPU.
3872 cpu = cpumask_next(cpu, cpu_online_mask);
3873 if (cpu >= nr_cpu_ids)
3874 cpu = cpumask_next(-1, cpu_online_mask);
3875 WARN_ON_ONCE(cpu >= nr_cpu_ids);
3876 // Move to that CPU, if can't do so, retry later.
3877 if (torture_sched_setaffinity(current->pid, cpumask_of(cpu), false))
3878 continue;
3879 // Preempt at high-ish priority, then reset to normal.
3880 sched_set_fifo(current);
3881 torture_sched_setaffinity(current->pid, cpu_present_mask, true);
3882 mdelay(preempt_duration);
3883 sched_set_normal(current, 0);
3884 stutter_wait("rcu_torture_preempt");
3885 } while (!torture_must_stop());
3886 torture_kthread_stopping("rcu_torture_preempt");
3887 return 0;
3888 }
3889
3890 static enum cpuhp_state rcutor_hp;
3891
3892 static struct hrtimer gpwrap_lag_timer;
3893 static bool gpwrap_lag_active;
3894
3895 /* Timer handler for toggling RCU grace-period sequence overflow test lag value */
rcu_gpwrap_lag_timer(struct hrtimer * timer)3896 static enum hrtimer_restart rcu_gpwrap_lag_timer(struct hrtimer *timer)
3897 {
3898 ktime_t next_delay;
3899
3900 if (gpwrap_lag_active) {
3901 pr_alert("rcu-torture: Disabling gpwrap lag (value=0)\n");
3902 cur_ops->set_gpwrap_lag(0);
3903 gpwrap_lag_active = false;
3904 next_delay = ktime_set((gpwrap_lag_cycle_mins - gpwrap_lag_active_mins) * 60, 0);
3905 } else {
3906 pr_alert("rcu-torture: Enabling gpwrap lag (value=%d)\n", gpwrap_lag_gps);
3907 cur_ops->set_gpwrap_lag(gpwrap_lag_gps);
3908 gpwrap_lag_active = true;
3909 next_delay = ktime_set(gpwrap_lag_active_mins * 60, 0);
3910 }
3911
3912 if (torture_must_stop_irq())
3913 return HRTIMER_NORESTART;
3914
3915 hrtimer_forward_now(timer, next_delay);
3916 return HRTIMER_RESTART;
3917 }
3918
rcu_gpwrap_lag_init(void)3919 static int rcu_gpwrap_lag_init(void)
3920 {
3921 if (!gpwrap_lag)
3922 return 0;
3923
3924 if (gpwrap_lag_cycle_mins <= 0 || gpwrap_lag_active_mins <= 0) {
3925 pr_alert("rcu-torture: lag timing parameters must be positive\n");
3926 return -EINVAL;
3927 }
3928
3929 hrtimer_setup(&gpwrap_lag_timer, rcu_gpwrap_lag_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
3930 gpwrap_lag_active = false;
3931 hrtimer_start(&gpwrap_lag_timer,
3932 ktime_set((gpwrap_lag_cycle_mins - gpwrap_lag_active_mins) * 60, 0), HRTIMER_MODE_REL);
3933
3934 return 0;
3935 }
3936
rcu_gpwrap_lag_cleanup(void)3937 static void rcu_gpwrap_lag_cleanup(void)
3938 {
3939 hrtimer_cancel(&gpwrap_lag_timer);
3940 cur_ops->set_gpwrap_lag(0);
3941 gpwrap_lag_active = false;
3942 }
3943 static void
rcu_torture_cleanup(void)3944 rcu_torture_cleanup(void)
3945 {
3946 int firsttime;
3947 int flags = 0;
3948 unsigned long gp_seq = 0;
3949 int i;
3950 int j;
3951
3952 if (torture_cleanup_begin()) {
3953 if (cur_ops->cb_barrier != NULL) {
3954 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
3955 cur_ops->cb_barrier();
3956 }
3957 if (cur_ops->gp_slow_unregister)
3958 cur_ops->gp_slow_unregister(NULL);
3959 return;
3960 }
3961 if (!cur_ops) {
3962 torture_cleanup_end();
3963 return;
3964 }
3965
3966 rcutorture_test_nmis(test_nmis);
3967
3968 if (cur_ops->gp_kthread_dbg)
3969 cur_ops->gp_kthread_dbg();
3970 torture_stop_kthread(rcu_torture_preempt, preempt_task);
3971 rcu_torture_read_exit_cleanup();
3972 rcu_torture_barrier_cleanup();
3973 rcu_torture_fwd_prog_cleanup();
3974 torture_stop_kthread(rcu_torture_stall, stall_task);
3975 torture_stop_kthread(rcu_torture_writer, writer_task);
3976
3977 if (nocb_tasks) {
3978 for (i = 0; i < nrealnocbers; i++)
3979 torture_stop_kthread(rcu_nocb_toggle, nocb_tasks[i]);
3980 kfree(nocb_tasks);
3981 nocb_tasks = NULL;
3982 }
3983
3984 if (updown_task) {
3985 torture_stop_kthread(rcu_torture_updown, updown_task);
3986 updown_task = NULL;
3987 }
3988 if (reader_tasks) {
3989 for (i = 0; i < nrealreaders; i++)
3990 torture_stop_kthread(rcu_torture_reader,
3991 reader_tasks[i]);
3992 kfree(reader_tasks);
3993 reader_tasks = NULL;
3994 }
3995 kfree(rcu_torture_reader_mbchk);
3996 rcu_torture_reader_mbchk = NULL;
3997
3998 if (fakewriter_tasks) {
3999 for (i = 0; i < nrealfakewriters; i++)
4000 torture_stop_kthread(rcu_torture_fakewriter,
4001 fakewriter_tasks[i]);
4002 kfree(fakewriter_tasks);
4003 fakewriter_tasks = NULL;
4004 }
4005
4006 if (cur_ops->get_gp_data)
4007 cur_ops->get_gp_data(&flags, &gp_seq);
4008 pr_alert("%s: End-test grace-period state: g%ld f%#x total-gps=%ld\n",
4009 cur_ops->name, (long)gp_seq, flags,
4010 rcutorture_seq_diff(gp_seq, start_gp_seq));
4011 torture_stop_kthread(rcu_torture_stats, stats_task);
4012 torture_stop_kthread(rcu_torture_fqs, fqs_task);
4013 if (rcu_torture_can_boost() && rcutor_hp >= 0)
4014 cpuhp_remove_state(rcutor_hp);
4015
4016 /*
4017 * Wait for all RCU callbacks to fire, then do torture-type-specific
4018 * cleanup operations.
4019 */
4020 if (cur_ops->cb_barrier != NULL) {
4021 pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
4022 cur_ops->cb_barrier();
4023 }
4024 if (cur_ops->cleanup != NULL)
4025 cur_ops->cleanup();
4026
4027 rcu_torture_mem_dump_obj();
4028
4029 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
4030
4031 if (err_segs_recorded) {
4032 pr_alert("Failure/close-call rcutorture reader segments:\n");
4033 if (rt_read_nsegs == 0)
4034 pr_alert("\t: No segments recorded!!!\n");
4035 firsttime = 1;
4036 for (i = 0; i < rt_read_nsegs; i++) {
4037 if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_GP))
4038 pr_alert("\t%lluus ", div64_u64(err_segs[i].rt_ts, 1000ULL));
4039 else
4040 pr_alert("\t");
4041 pr_cont("%d: %#4x", i, err_segs[i].rt_readstate);
4042 if (err_segs[i].rt_delay_jiffies != 0) {
4043 pr_cont("%s%ldjiffies", firsttime ? "" : "+",
4044 err_segs[i].rt_delay_jiffies);
4045 firsttime = 0;
4046 }
4047 if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_CPU)) {
4048 pr_cont(" CPU %2d", err_segs[i].rt_cpu);
4049 if (err_segs[i].rt_cpu != err_segs[i].rt_end_cpu)
4050 pr_cont("->%-2d", err_segs[i].rt_end_cpu);
4051 else
4052 pr_cont(" ...");
4053 }
4054 if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_LOG_GP) &&
4055 cur_ops->gather_gp_seqs && cur_ops->format_gp_seqs) {
4056 char buf1[20+1];
4057 char buf2[20+1];
4058 char sepchar = '-';
4059
4060 cur_ops->format_gp_seqs(err_segs[i].rt_gp_seq,
4061 buf1, ARRAY_SIZE(buf1));
4062 cur_ops->format_gp_seqs(err_segs[i].rt_gp_seq_end,
4063 buf2, ARRAY_SIZE(buf2));
4064 if (err_segs[i].rt_gp_seq == err_segs[i].rt_gp_seq_end) {
4065 if (buf2[0]) {
4066 for (j = 0; buf2[j]; j++)
4067 buf2[j] = '.';
4068 if (j)
4069 buf2[j - 1] = ' ';
4070 }
4071 sepchar = ' ';
4072 }
4073 pr_cont(" %s%c%s", buf1, sepchar, buf2);
4074 }
4075 if (err_segs[i].rt_delay_ms != 0) {
4076 pr_cont(" %s%ldms", firsttime ? "" : "+",
4077 err_segs[i].rt_delay_ms);
4078 firsttime = 0;
4079 }
4080 if (err_segs[i].rt_delay_us != 0) {
4081 pr_cont(" %s%ldus", firsttime ? "" : "+",
4082 err_segs[i].rt_delay_us);
4083 firsttime = 0;
4084 }
4085 pr_cont("%s", err_segs[i].rt_preempted ? " preempted" : "");
4086 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_BH)
4087 pr_cont(" BH");
4088 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_IRQ)
4089 pr_cont(" IRQ");
4090 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_PREEMPT)
4091 pr_cont(" PREEMPT");
4092 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RBH)
4093 pr_cont(" RBH");
4094 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_SCHED)
4095 pr_cont(" SCHED");
4096 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RCU_1)
4097 pr_cont(" RCU_1");
4098 if (err_segs[i].rt_readstate & RCUTORTURE_RDR_RCU_2)
4099 pr_cont(" RCU_2");
4100 pr_cont("\n");
4101
4102 }
4103 if (rt_read_preempted)
4104 pr_alert("\tReader was preempted.\n");
4105 }
4106 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
4107 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
4108 else if (torture_onoff_failures())
4109 rcu_torture_print_module_parms(cur_ops,
4110 "End of test: RCU_HOTPLUG");
4111 else
4112 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
4113 torture_cleanup_end();
4114 if (cur_ops->gp_slow_unregister)
4115 cur_ops->gp_slow_unregister(NULL);
4116
4117 if (gpwrap_lag && cur_ops->set_gpwrap_lag)
4118 rcu_gpwrap_lag_cleanup();
4119 }
4120
rcu_torture_leak_cb(struct rcu_head * rhp)4121 static void rcu_torture_leak_cb(struct rcu_head *rhp)
4122 {
4123 }
4124
rcu_torture_err_cb(struct rcu_head * rhp)4125 static void rcu_torture_err_cb(struct rcu_head *rhp)
4126 {
4127 /*
4128 * This -might- happen due to race conditions, but is unlikely.
4129 * The scenario that leads to this happening is that the
4130 * first of the pair of duplicate callbacks is queued,
4131 * someone else starts a grace period that includes that
4132 * callback, then the second of the pair must wait for the
4133 * next grace period. Unlikely, but can happen. If it
4134 * does happen, the debug-objects subsystem won't have splatted.
4135 */
4136 pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
4137 }
4138
4139 /*
4140 * Verify that double-free causes debug-objects to complain, but only
4141 * if CONFIG_DEBUG_OBJECTS_RCU_HEAD=y. Otherwise, say that the test
4142 * cannot be carried out.
4143 */
rcu_test_debug_objects(void)4144 static void rcu_test_debug_objects(void)
4145 {
4146 struct rcu_head rh1;
4147 struct rcu_head rh2;
4148 int idx;
4149
4150 if (!IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD)) {
4151 pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_%s()\n",
4152 KBUILD_MODNAME, cur_ops->name);
4153 return;
4154 }
4155
4156 if (WARN_ON_ONCE(cur_ops->debug_objects &&
4157 (!cur_ops->call || !cur_ops->cb_barrier)))
4158 return;
4159
4160 struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
4161
4162 init_rcu_head_on_stack(&rh1);
4163 init_rcu_head_on_stack(&rh2);
4164 pr_alert("%s: WARN: Duplicate call_%s() test starting.\n", KBUILD_MODNAME, cur_ops->name);
4165
4166 /* Try to queue the rh2 pair of callbacks for the same grace period. */
4167 idx = cur_ops->readlock(); /* Make it impossible to finish a grace period. */
4168 cur_ops->call(&rh1, rcu_torture_leak_cb); /* Start grace period. */
4169 cur_ops->call(&rh2, rcu_torture_leak_cb);
4170 cur_ops->call(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
4171 if (rhp) {
4172 cur_ops->call(rhp, rcu_torture_leak_cb);
4173 cur_ops->call(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
4174 }
4175 cur_ops->readunlock(idx);
4176
4177 /* Wait for them all to get done so we can safely return. */
4178 cur_ops->cb_barrier();
4179 pr_alert("%s: WARN: Duplicate call_%s() test complete.\n", KBUILD_MODNAME, cur_ops->name);
4180 destroy_rcu_head_on_stack(&rh1);
4181 destroy_rcu_head_on_stack(&rh2);
4182 kfree(rhp);
4183 }
4184
rcutorture_sync(void)4185 static void rcutorture_sync(void)
4186 {
4187 static unsigned long n;
4188
4189 if (cur_ops->sync && !(++n & 0xfff))
4190 cur_ops->sync();
4191 }
4192
4193 static DEFINE_MUTEX(mut0);
4194 static DEFINE_MUTEX(mut1);
4195 static DEFINE_MUTEX(mut2);
4196 static DEFINE_MUTEX(mut3);
4197 static DEFINE_MUTEX(mut4);
4198 static DEFINE_MUTEX(mut5);
4199 static DEFINE_MUTEX(mut6);
4200 static DEFINE_MUTEX(mut7);
4201 static DEFINE_MUTEX(mut8);
4202 static DEFINE_MUTEX(mut9);
4203
4204 static DECLARE_RWSEM(rwsem0);
4205 static DECLARE_RWSEM(rwsem1);
4206 static DECLARE_RWSEM(rwsem2);
4207 static DECLARE_RWSEM(rwsem3);
4208 static DECLARE_RWSEM(rwsem4);
4209 static DECLARE_RWSEM(rwsem5);
4210 static DECLARE_RWSEM(rwsem6);
4211 static DECLARE_RWSEM(rwsem7);
4212 static DECLARE_RWSEM(rwsem8);
4213 static DECLARE_RWSEM(rwsem9);
4214
4215 DEFINE_STATIC_SRCU(srcu0);
4216 DEFINE_STATIC_SRCU(srcu1);
4217 DEFINE_STATIC_SRCU(srcu2);
4218 DEFINE_STATIC_SRCU(srcu3);
4219 DEFINE_STATIC_SRCU(srcu4);
4220 DEFINE_STATIC_SRCU(srcu5);
4221 DEFINE_STATIC_SRCU(srcu6);
4222 DEFINE_STATIC_SRCU(srcu7);
4223 DEFINE_STATIC_SRCU(srcu8);
4224 DEFINE_STATIC_SRCU(srcu9);
4225
srcu_lockdep_next(const char * f,const char * fl,const char * fs,const char * fu,int i,int cyclelen,int deadlock)4226 static int srcu_lockdep_next(const char *f, const char *fl, const char *fs, const char *fu, int i,
4227 int cyclelen, int deadlock)
4228 {
4229 int j = i + 1;
4230
4231 if (j >= cyclelen)
4232 j = deadlock ? 0 : -1;
4233 if (j >= 0)
4234 pr_info("%s: %s(%d), %s(%d), %s(%d)\n", f, fl, i, fs, j, fu, i);
4235 else
4236 pr_info("%s: %s(%d), %s(%d)\n", f, fl, i, fu, i);
4237 return j;
4238 }
4239
4240 // Test lockdep on SRCU-based deadlock scenarios.
rcu_torture_init_srcu_lockdep(void)4241 static void rcu_torture_init_srcu_lockdep(void)
4242 {
4243 int cyclelen;
4244 int deadlock;
4245 bool err = false;
4246 int i;
4247 int j;
4248 int idx;
4249 struct mutex *muts[] = { &mut0, &mut1, &mut2, &mut3, &mut4,
4250 &mut5, &mut6, &mut7, &mut8, &mut9 };
4251 struct rw_semaphore *rwsems[] = { &rwsem0, &rwsem1, &rwsem2, &rwsem3, &rwsem4,
4252 &rwsem5, &rwsem6, &rwsem7, &rwsem8, &rwsem9 };
4253 struct srcu_struct *srcus[] = { &srcu0, &srcu1, &srcu2, &srcu3, &srcu4,
4254 &srcu5, &srcu6, &srcu7, &srcu8, &srcu9 };
4255 int testtype;
4256
4257 if (!test_srcu_lockdep)
4258 return;
4259
4260 deadlock = test_srcu_lockdep / 1000;
4261 testtype = (test_srcu_lockdep / 10) % 100;
4262 cyclelen = test_srcu_lockdep % 10;
4263 WARN_ON_ONCE(ARRAY_SIZE(muts) != ARRAY_SIZE(srcus));
4264 if (WARN_ONCE(deadlock != !!deadlock,
4265 "%s: test_srcu_lockdep=%d and deadlock digit %d must be zero or one.\n",
4266 __func__, test_srcu_lockdep, deadlock))
4267 err = true;
4268 if (WARN_ONCE(cyclelen <= 0,
4269 "%s: test_srcu_lockdep=%d and cycle-length digit %d must be greater than zero.\n",
4270 __func__, test_srcu_lockdep, cyclelen))
4271 err = true;
4272 if (err)
4273 goto err_out;
4274
4275 if (testtype == 0) {
4276 pr_info("%s: test_srcu_lockdep = %05d: SRCU %d-way %sdeadlock.\n",
4277 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
4278 if (deadlock && cyclelen == 1)
4279 pr_info("%s: Expect hang.\n", __func__);
4280 for (i = 0; i < cyclelen; i++) {
4281 j = srcu_lockdep_next(__func__, "srcu_read_lock", "synchronize_srcu",
4282 "srcu_read_unlock", i, cyclelen, deadlock);
4283 idx = srcu_read_lock(srcus[i]);
4284 if (j >= 0)
4285 synchronize_srcu(srcus[j]);
4286 srcu_read_unlock(srcus[i], idx);
4287 }
4288 return;
4289 }
4290
4291 if (testtype == 1) {
4292 pr_info("%s: test_srcu_lockdep = %05d: SRCU/mutex %d-way %sdeadlock.\n",
4293 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
4294 for (i = 0; i < cyclelen; i++) {
4295 pr_info("%s: srcu_read_lock(%d), mutex_lock(%d), mutex_unlock(%d), srcu_read_unlock(%d)\n",
4296 __func__, i, i, i, i);
4297 idx = srcu_read_lock(srcus[i]);
4298 mutex_lock(muts[i]);
4299 mutex_unlock(muts[i]);
4300 srcu_read_unlock(srcus[i], idx);
4301
4302 j = srcu_lockdep_next(__func__, "mutex_lock", "synchronize_srcu",
4303 "mutex_unlock", i, cyclelen, deadlock);
4304 mutex_lock(muts[i]);
4305 if (j >= 0)
4306 synchronize_srcu(srcus[j]);
4307 mutex_unlock(muts[i]);
4308 }
4309 return;
4310 }
4311
4312 if (testtype == 2) {
4313 pr_info("%s: test_srcu_lockdep = %05d: SRCU/rwsem %d-way %sdeadlock.\n",
4314 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
4315 for (i = 0; i < cyclelen; i++) {
4316 pr_info("%s: srcu_read_lock(%d), down_read(%d), up_read(%d), srcu_read_unlock(%d)\n",
4317 __func__, i, i, i, i);
4318 idx = srcu_read_lock(srcus[i]);
4319 down_read(rwsems[i]);
4320 up_read(rwsems[i]);
4321 srcu_read_unlock(srcus[i], idx);
4322
4323 j = srcu_lockdep_next(__func__, "down_write", "synchronize_srcu",
4324 "up_write", i, cyclelen, deadlock);
4325 down_write(rwsems[i]);
4326 if (j >= 0)
4327 synchronize_srcu(srcus[j]);
4328 up_write(rwsems[i]);
4329 }
4330 return;
4331 }
4332
4333 #ifdef CONFIG_TASKS_TRACE_RCU
4334 if (testtype == 3) {
4335 pr_info("%s: test_srcu_lockdep = %05d: SRCU and Tasks Trace RCU %d-way %sdeadlock.\n",
4336 __func__, test_srcu_lockdep, cyclelen, deadlock ? "" : "non-");
4337 if (deadlock && cyclelen == 1)
4338 pr_info("%s: Expect hang.\n", __func__);
4339 for (i = 0; i < cyclelen; i++) {
4340 char *fl = i == 0 ? "rcu_read_lock_trace" : "srcu_read_lock";
4341 char *fs = i == cyclelen - 1 ? "synchronize_rcu_tasks_trace"
4342 : "synchronize_srcu";
4343 char *fu = i == 0 ? "rcu_read_unlock_trace" : "srcu_read_unlock";
4344
4345 j = srcu_lockdep_next(__func__, fl, fs, fu, i, cyclelen, deadlock);
4346 if (i == 0)
4347 rcu_read_lock_trace();
4348 else
4349 idx = srcu_read_lock(srcus[i]);
4350 if (j >= 0) {
4351 if (i == cyclelen - 1)
4352 synchronize_rcu_tasks_trace();
4353 else
4354 synchronize_srcu(srcus[j]);
4355 }
4356 if (i == 0)
4357 rcu_read_unlock_trace();
4358 else
4359 srcu_read_unlock(srcus[i], idx);
4360 }
4361 return;
4362 }
4363 #endif // #ifdef CONFIG_TASKS_TRACE_RCU
4364
4365 err_out:
4366 pr_info("%s: test_srcu_lockdep = %05d does nothing.\n", __func__, test_srcu_lockdep);
4367 pr_info("%s: test_srcu_lockdep = DNNL.\n", __func__);
4368 pr_info("%s: D: Deadlock if nonzero.\n", __func__);
4369 pr_info("%s: NN: Test number, 0=SRCU, 1=SRCU/mutex, 2=SRCU/rwsem, 3=SRCU/Tasks Trace RCU.\n", __func__);
4370 pr_info("%s: L: Cycle length.\n", __func__);
4371 if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU))
4372 pr_info("%s: NN=3 disallowed because kernel is built with CONFIG_TASKS_TRACE_RCU=n\n", __func__);
4373 }
4374
4375 static int __init
rcu_torture_init(void)4376 rcu_torture_init(void)
4377 {
4378 long i;
4379 int cpu;
4380 int firsterr = 0;
4381 int flags = 0;
4382 unsigned long gp_seq = 0;
4383 static struct rcu_torture_ops *torture_ops[] = {
4384 &rcu_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, &busted_srcud_ops,
4385 TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
4386 &trivial_ops,
4387 };
4388
4389 if (!torture_init_begin(torture_type, verbose))
4390 return -EBUSY;
4391
4392 /* Process args and tell the world that the torturer is on the job. */
4393 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
4394 cur_ops = torture_ops[i];
4395 if (strcmp(torture_type, cur_ops->name) == 0)
4396 break;
4397 }
4398 if (i == ARRAY_SIZE(torture_ops)) {
4399 pr_alert("rcu-torture: invalid torture type: \"%s\"\n",
4400 torture_type);
4401 pr_alert("rcu-torture types:");
4402 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
4403 pr_cont(" %s", torture_ops[i]->name);
4404 pr_cont("\n");
4405 firsterr = -EINVAL;
4406 cur_ops = NULL;
4407 goto unwind;
4408 }
4409 if (cur_ops->fqs == NULL && fqs_duration != 0) {
4410 pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
4411 fqs_duration = 0;
4412 }
4413 if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
4414 !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
4415 pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
4416 cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
4417 nocbs_nthreads = 0;
4418 }
4419 if (cur_ops->init)
4420 cur_ops->init();
4421
4422 rcu_torture_init_srcu_lockdep();
4423
4424 if (nfakewriters >= 0) {
4425 nrealfakewriters = nfakewriters;
4426 } else {
4427 nrealfakewriters = num_online_cpus() - 2 - nfakewriters;
4428 if (nrealfakewriters <= 0)
4429 nrealfakewriters = 1;
4430 }
4431
4432 if (nreaders >= 0) {
4433 nrealreaders = nreaders;
4434 } else {
4435 nrealreaders = num_online_cpus() - 2 - nreaders;
4436 if (nrealreaders <= 0)
4437 nrealreaders = 1;
4438 }
4439 rcu_torture_print_module_parms(cur_ops, "Start of test");
4440 if (cur_ops->get_gp_data)
4441 cur_ops->get_gp_data(&flags, &gp_seq);
4442 start_gp_seq = gp_seq;
4443 pr_alert("%s: Start-test grace-period state: g%ld f%#x\n",
4444 cur_ops->name, (long)gp_seq, flags);
4445
4446 /* Set up the freelist. */
4447
4448 INIT_LIST_HEAD(&rcu_torture_freelist);
4449 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
4450 rcu_tortures[i].rtort_mbtest = 0;
4451 list_add_tail(&rcu_tortures[i].rtort_free,
4452 &rcu_torture_freelist);
4453 }
4454
4455 /* Initialize the statistics so that each run gets its own numbers. */
4456
4457 rcu_torture_current = NULL;
4458 rcu_torture_current_version = 0;
4459 atomic_set(&n_rcu_torture_alloc, 0);
4460 atomic_set(&n_rcu_torture_alloc_fail, 0);
4461 atomic_set(&n_rcu_torture_free, 0);
4462 atomic_set(&n_rcu_torture_mberror, 0);
4463 atomic_set(&n_rcu_torture_mbchk_fail, 0);
4464 atomic_set(&n_rcu_torture_mbchk_tries, 0);
4465 atomic_set(&n_rcu_torture_error, 0);
4466 n_rcu_torture_barrier_error = 0;
4467 n_rcu_torture_boost_ktrerror = 0;
4468 n_rcu_torture_boost_failure = 0;
4469 n_rcu_torture_boosts = 0;
4470 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
4471 atomic_set(&rcu_torture_wcount[i], 0);
4472 for_each_possible_cpu(cpu) {
4473 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
4474 per_cpu(rcu_torture_count, cpu)[i] = 0;
4475 per_cpu(rcu_torture_batch, cpu)[i] = 0;
4476 }
4477 }
4478 err_segs_recorded = 0;
4479 rt_read_nsegs = 0;
4480
4481 /* Start up the kthreads. */
4482
4483 rcu_torture_write_types();
4484 if (nrealfakewriters > 0) {
4485 fakewriter_tasks = kcalloc(nrealfakewriters,
4486 sizeof(fakewriter_tasks[0]),
4487 GFP_KERNEL);
4488 if (fakewriter_tasks == NULL) {
4489 TOROUT_ERRSTRING("out of memory");
4490 firsterr = -ENOMEM;
4491 goto unwind;
4492 }
4493 }
4494 for (i = 0; i < nrealfakewriters; i++) {
4495 firsterr = torture_create_kthread(rcu_torture_fakewriter,
4496 NULL, fakewriter_tasks[i]);
4497 if (torture_init_error(firsterr))
4498 goto unwind;
4499 }
4500 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
4501 GFP_KERNEL);
4502 rcu_torture_reader_mbchk = kcalloc(nrealreaders, sizeof(*rcu_torture_reader_mbchk),
4503 GFP_KERNEL);
4504 if (!reader_tasks || !rcu_torture_reader_mbchk) {
4505 TOROUT_ERRSTRING("out of memory");
4506 firsterr = -ENOMEM;
4507 goto unwind;
4508 }
4509 for (i = 0; i < nrealreaders; i++) {
4510 rcu_torture_reader_mbchk[i].rtc_chkrdr = -1;
4511 firsterr = torture_create_kthread(rcu_torture_reader, (void *)i,
4512 reader_tasks[i]);
4513 if (torture_init_error(firsterr))
4514 goto unwind;
4515 }
4516
4517 firsterr = torture_create_kthread(rcu_torture_writer, NULL,
4518 writer_task);
4519 if (torture_init_error(firsterr))
4520 goto unwind;
4521
4522 firsterr = rcu_torture_updown_init();
4523 if (torture_init_error(firsterr))
4524 goto unwind;
4525 nrealnocbers = nocbs_nthreads;
4526 if (WARN_ON(nrealnocbers < 0))
4527 nrealnocbers = 1;
4528 if (WARN_ON(nocbs_toggle < 0))
4529 nocbs_toggle = HZ;
4530 if (nrealnocbers > 0) {
4531 nocb_tasks = kcalloc(nrealnocbers, sizeof(nocb_tasks[0]), GFP_KERNEL);
4532 if (nocb_tasks == NULL) {
4533 TOROUT_ERRSTRING("out of memory");
4534 firsterr = -ENOMEM;
4535 goto unwind;
4536 }
4537 } else {
4538 nocb_tasks = NULL;
4539 }
4540 for (i = 0; i < nrealnocbers; i++) {
4541 firsterr = torture_create_kthread(rcu_nocb_toggle, NULL, nocb_tasks[i]);
4542 if (torture_init_error(firsterr))
4543 goto unwind;
4544 }
4545 if (stat_interval > 0) {
4546 firsterr = torture_create_kthread(rcu_torture_stats, NULL,
4547 stats_task);
4548 if (torture_init_error(firsterr))
4549 goto unwind;
4550 }
4551 if (test_no_idle_hz && shuffle_interval > 0) {
4552 firsterr = torture_shuffle_init(shuffle_interval * HZ);
4553 if (torture_init_error(firsterr))
4554 goto unwind;
4555 }
4556 if (stutter < 0)
4557 stutter = 0;
4558 if (stutter) {
4559 int t;
4560
4561 t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ;
4562 firsterr = torture_stutter_init(stutter * HZ, t);
4563 if (torture_init_error(firsterr))
4564 goto unwind;
4565 }
4566 if (fqs_duration < 0)
4567 fqs_duration = 0;
4568 if (fqs_holdoff < 0)
4569 fqs_holdoff = 0;
4570 if (fqs_duration && fqs_holdoff) {
4571 /* Create the fqs thread */
4572 firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
4573 fqs_task);
4574 if (torture_init_error(firsterr))
4575 goto unwind;
4576 }
4577 if (test_boost_interval < 1)
4578 test_boost_interval = 1;
4579 if (test_boost_duration < 2)
4580 test_boost_duration = 2;
4581 if (rcu_torture_can_boost()) {
4582
4583 boost_starttime = jiffies + test_boost_interval * HZ;
4584
4585 firsterr = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "RCU_TORTURE",
4586 rcutorture_booster_init,
4587 rcutorture_booster_cleanup);
4588 rcutor_hp = firsterr;
4589 if (torture_init_error(firsterr))
4590 goto unwind;
4591 }
4592 shutdown_jiffies = jiffies + shutdown_secs * HZ;
4593 firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
4594 if (torture_init_error(firsterr))
4595 goto unwind;
4596 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval,
4597 rcutorture_sync);
4598 if (torture_init_error(firsterr))
4599 goto unwind;
4600 firsterr = rcu_torture_stall_init();
4601 if (torture_init_error(firsterr))
4602 goto unwind;
4603 firsterr = rcu_torture_fwd_prog_init();
4604 if (torture_init_error(firsterr))
4605 goto unwind;
4606 firsterr = rcu_torture_barrier_init();
4607 if (torture_init_error(firsterr))
4608 goto unwind;
4609 firsterr = rcu_torture_read_exit_init();
4610 if (torture_init_error(firsterr))
4611 goto unwind;
4612 if (preempt_duration > 0) {
4613 firsterr = torture_create_kthread(rcu_torture_preempt, NULL, preempt_task);
4614 if (torture_init_error(firsterr))
4615 goto unwind;
4616 }
4617 if (object_debug)
4618 rcu_test_debug_objects();
4619
4620 if (cur_ops->gp_slow_register && !WARN_ON_ONCE(!cur_ops->gp_slow_unregister))
4621 cur_ops->gp_slow_register(&rcu_fwd_cb_nodelay);
4622
4623 if (gpwrap_lag && cur_ops->set_gpwrap_lag) {
4624 firsterr = rcu_gpwrap_lag_init();
4625 if (torture_init_error(firsterr))
4626 goto unwind;
4627 }
4628
4629 torture_init_end();
4630 return 0;
4631
4632 unwind:
4633 torture_init_end();
4634 rcu_torture_cleanup();
4635 if (shutdown_secs) {
4636 WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
4637 kernel_power_off();
4638 }
4639 return firsterr;
4640 }
4641
4642 module_init(rcu_torture_init);
4643 module_exit(rcu_torture_cleanup);
4644