1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Common functions for in-kernel torture tests. 4 * 5 * Copyright (C) IBM Corporation, 2014 6 * 7 * Author: Paul E. McKenney <paulmck@linux.ibm.com> 8 * Based on kernel/rcu/torture.c. 9 */ 10 11 #define pr_fmt(fmt) fmt 12 13 #include <linux/types.h> 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/kthread.h> 18 #include <linux/err.h> 19 #include <linux/spinlock.h> 20 #include <linux/smp.h> 21 #include <linux/interrupt.h> 22 #include <linux/sched.h> 23 #include <linux/sched/clock.h> 24 #include <linux/atomic.h> 25 #include <linux/bitops.h> 26 #include <linux/completion.h> 27 #include <linux/moduleparam.h> 28 #include <linux/percpu.h> 29 #include <linux/notifier.h> 30 #include <linux/reboot.h> 31 #include <linux/freezer.h> 32 #include <linux/cpu.h> 33 #include <linux/delay.h> 34 #include <linux/stat.h> 35 #include <linux/slab.h> 36 #include <linux/trace_clock.h> 37 #include <linux/ktime.h> 38 #include <asm/byteorder.h> 39 #include <linux/torture.h> 40 #include <linux/sched/rt.h> 41 #include "rcu/rcu.h" 42 43 MODULE_LICENSE("GPL"); 44 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); 45 46 static bool disable_onoff_at_boot; 47 module_param(disable_onoff_at_boot, bool, 0444); 48 49 static bool ftrace_dump_at_shutdown; 50 module_param(ftrace_dump_at_shutdown, bool, 0444); 51 52 static int verbose_sleep_frequency; 53 module_param(verbose_sleep_frequency, int, 0444); 54 55 static int verbose_sleep_duration = 1; 56 module_param(verbose_sleep_duration, int, 0444); 57 58 static int random_shuffle; 59 module_param(random_shuffle, int, 0444); 60 61 static char *torture_type; 62 static int verbose; 63 64 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ 65 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */ 66 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */ 67 #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */ 68 static int fullstop = FULLSTOP_RMMOD; 69 static DEFINE_MUTEX(fullstop_mutex); 70 71 static atomic_t verbose_sleep_counter; 72 73 /* 74 * Sleep if needed from VERBOSE_TOROUT*(). 75 */ 76 void verbose_torout_sleep(void) 77 { 78 if (verbose_sleep_frequency > 0 && 79 verbose_sleep_duration > 0 && 80 !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency)) 81 schedule_timeout_uninterruptible(verbose_sleep_duration); 82 } 83 EXPORT_SYMBOL_GPL(verbose_torout_sleep); 84 85 /* 86 * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit 87 * nanosecond random fuzz. This function and its friends desynchronize 88 * testing from the timer wheel. 89 */ 90 int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, const enum hrtimer_mode mode, 91 struct torture_random_state *trsp) 92 { 93 ktime_t hto = baset_ns; 94 95 if (trsp) 96 hto += torture_random(trsp) % fuzzt_ns; 97 set_current_state(TASK_IDLE); 98 return schedule_hrtimeout(&hto, mode); 99 } 100 EXPORT_SYMBOL_GPL(torture_hrtimeout_ns); 101 102 /* 103 * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit 104 * nanosecond (not microsecond!) random fuzz. 105 */ 106 int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp) 107 { 108 ktime_t baset_ns = baset_us * NSEC_PER_USEC; 109 110 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp); 111 } 112 EXPORT_SYMBOL_GPL(torture_hrtimeout_us); 113 114 /* 115 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit 116 * microsecond (not millisecond!) random fuzz. 117 */ 118 int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp) 119 { 120 ktime_t baset_ns = baset_ms * NSEC_PER_MSEC; 121 u32 fuzzt_ns; 122 123 if ((u32)~0U / NSEC_PER_USEC < fuzzt_us) 124 fuzzt_ns = (u32)~0U; 125 else 126 fuzzt_ns = fuzzt_us * NSEC_PER_USEC; 127 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp); 128 } 129 EXPORT_SYMBOL_GPL(torture_hrtimeout_ms); 130 131 /* 132 * Schedule a high-resolution-timer sleep in jiffies, with an 133 * implied one-jiffy random fuzz. This is intended to replace calls to 134 * schedule_timeout_interruptible() and friends. 135 */ 136 int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp) 137 { 138 ktime_t baset_ns = jiffies_to_nsecs(baset_j); 139 140 return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), HRTIMER_MODE_REL, trsp); 141 } 142 EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies); 143 144 /* 145 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit 146 * millisecond (not second!) random fuzz. 147 */ 148 int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp) 149 { 150 ktime_t baset_ns = baset_s * NSEC_PER_SEC; 151 u32 fuzzt_ns; 152 153 if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms) 154 fuzzt_ns = (u32)~0U; 155 else 156 fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC; 157 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, HRTIMER_MODE_REL, trsp); 158 } 159 EXPORT_SYMBOL_GPL(torture_hrtimeout_s); 160 161 #ifdef CONFIG_HOTPLUG_CPU 162 163 /* 164 * Variables for online-offline handling. Only present if CPU hotplug 165 * is enabled, otherwise does nothing. 166 */ 167 168 static struct task_struct *onoff_task; 169 static long onoff_holdoff; 170 static long onoff_interval; 171 static torture_ofl_func *onoff_f; 172 static long n_offline_attempts; 173 static long n_offline_successes; 174 static unsigned long sum_offline; 175 static int min_offline = -1; 176 static int max_offline; 177 static long n_online_attempts; 178 static long n_online_successes; 179 static unsigned long sum_online; 180 static int min_online = -1; 181 static int max_online; 182 183 static int torture_online_cpus = NR_CPUS; 184 185 /* 186 * Some torture testing leverages confusion as to the number of online 187 * CPUs. This function returns the torture-testing view of this number, 188 * which allows torture tests to load-balance appropriately. 189 */ 190 int torture_num_online_cpus(void) 191 { 192 return READ_ONCE(torture_online_cpus); 193 } 194 EXPORT_SYMBOL_GPL(torture_num_online_cpus); 195 196 /* 197 * Attempt to take a CPU offline. Return false if the CPU is already 198 * offline or if it is not subject to CPU-hotplug operations. The 199 * caller can detect other failures by looking at the statistics. 200 */ 201 bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, 202 unsigned long *sum_offl, int *min_offl, int *max_offl) 203 { 204 unsigned long delta; 205 int ret; 206 char *s; 207 unsigned long starttime; 208 209 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) 210 return false; 211 if (num_online_cpus() <= 1) 212 return false; /* Can't offline the last CPU. */ 213 214 if (verbose > 1) 215 pr_alert("%s" TORTURE_FLAG 216 "torture_onoff task: offlining %d\n", 217 torture_type, cpu); 218 starttime = jiffies; 219 (*n_offl_attempts)++; 220 ret = remove_cpu(cpu); 221 if (ret) { 222 s = ""; 223 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) { 224 // PCI probe frequently disables hotplug during boot. 225 (*n_offl_attempts)--; 226 s = " (-EBUSY forgiven during boot)"; 227 } 228 if (verbose) 229 pr_alert("%s" TORTURE_FLAG 230 "torture_onoff task: offline %d failed%s: errno %d\n", 231 torture_type, cpu, s, ret); 232 } else { 233 if (verbose > 1) 234 pr_alert("%s" TORTURE_FLAG 235 "torture_onoff task: offlined %d\n", 236 torture_type, cpu); 237 if (onoff_f) 238 onoff_f(); 239 (*n_offl_successes)++; 240 delta = jiffies - starttime; 241 *sum_offl += delta; 242 if (*min_offl < 0) { 243 *min_offl = delta; 244 *max_offl = delta; 245 } 246 if (*min_offl > delta) 247 *min_offl = delta; 248 if (*max_offl < delta) 249 *max_offl = delta; 250 WRITE_ONCE(torture_online_cpus, torture_online_cpus - 1); 251 WARN_ON_ONCE(torture_online_cpus <= 0); 252 } 253 254 return true; 255 } 256 EXPORT_SYMBOL_GPL(torture_offline); 257 258 /* 259 * Attempt to bring a CPU online. Return false if the CPU is already 260 * online or if it is not subject to CPU-hotplug operations. The 261 * caller can detect other failures by looking at the statistics. 262 */ 263 bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, 264 unsigned long *sum_onl, int *min_onl, int *max_onl) 265 { 266 unsigned long delta; 267 int ret; 268 char *s; 269 unsigned long starttime; 270 271 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) 272 return false; 273 274 if (verbose > 1) 275 pr_alert("%s" TORTURE_FLAG 276 "torture_onoff task: onlining %d\n", 277 torture_type, cpu); 278 starttime = jiffies; 279 (*n_onl_attempts)++; 280 ret = add_cpu(cpu); 281 if (ret) { 282 s = ""; 283 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) { 284 // PCI probe frequently disables hotplug during boot. 285 (*n_onl_attempts)--; 286 s = " (-EBUSY forgiven during boot)"; 287 } 288 if (verbose) 289 pr_alert("%s" TORTURE_FLAG 290 "torture_onoff task: online %d failed%s: errno %d\n", 291 torture_type, cpu, s, ret); 292 } else { 293 if (verbose > 1) 294 pr_alert("%s" TORTURE_FLAG 295 "torture_onoff task: onlined %d\n", 296 torture_type, cpu); 297 (*n_onl_successes)++; 298 delta = jiffies - starttime; 299 *sum_onl += delta; 300 if (*min_onl < 0) { 301 *min_onl = delta; 302 *max_onl = delta; 303 } 304 if (*min_onl > delta) 305 *min_onl = delta; 306 if (*max_onl < delta) 307 *max_onl = delta; 308 WRITE_ONCE(torture_online_cpus, torture_online_cpus + 1); 309 } 310 311 return true; 312 } 313 EXPORT_SYMBOL_GPL(torture_online); 314 315 /* 316 * Get everything online at the beginning and ends of tests. 317 */ 318 static void torture_online_all(char *phase) 319 { 320 int cpu; 321 int ret; 322 323 for_each_possible_cpu(cpu) { 324 if (cpu_online(cpu)) 325 continue; 326 ret = add_cpu(cpu); 327 if (ret && verbose) { 328 pr_alert("%s" TORTURE_FLAG 329 "%s: %s online %d: errno %d\n", 330 __func__, phase, torture_type, cpu, ret); 331 } 332 } 333 } 334 335 /* 336 * Execute random CPU-hotplug operations at the interval specified 337 * by the onoff_interval. 338 */ 339 static int 340 torture_onoff(void *arg) 341 { 342 int cpu; 343 int maxcpu = -1; 344 DEFINE_TORTURE_RANDOM(rand); 345 346 VERBOSE_TOROUT_STRING("torture_onoff task started"); 347 for_each_online_cpu(cpu) 348 maxcpu = cpu; 349 WARN_ON(maxcpu < 0); 350 torture_online_all("Initial"); 351 if (maxcpu == 0) { 352 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled"); 353 goto stop; 354 } 355 356 if (onoff_holdoff > 0) { 357 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff"); 358 torture_hrtimeout_jiffies(onoff_holdoff, &rand); 359 VERBOSE_TOROUT_STRING("torture_onoff end holdoff"); 360 } 361 while (!torture_must_stop()) { 362 if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) { 363 torture_hrtimeout_jiffies(HZ / 10, &rand); 364 continue; 365 } 366 cpu = torture_random(&rand) % (maxcpu + 1); 367 if (!torture_offline(cpu, 368 &n_offline_attempts, &n_offline_successes, 369 &sum_offline, &min_offline, &max_offline)) 370 torture_online(cpu, 371 &n_online_attempts, &n_online_successes, 372 &sum_online, &min_online, &max_online); 373 torture_hrtimeout_jiffies(onoff_interval, &rand); 374 } 375 376 stop: 377 torture_kthread_stopping("torture_onoff"); 378 torture_online_all("Final"); 379 return 0; 380 } 381 382 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 383 384 /* 385 * Initiate online-offline handling. 386 */ 387 int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f) 388 { 389 #ifdef CONFIG_HOTPLUG_CPU 390 onoff_holdoff = ooholdoff; 391 onoff_interval = oointerval; 392 onoff_f = f; 393 if (onoff_interval <= 0) 394 return 0; 395 return torture_create_kthread(torture_onoff, NULL, onoff_task); 396 #else /* #ifdef CONFIG_HOTPLUG_CPU */ 397 return 0; 398 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ 399 } 400 EXPORT_SYMBOL_GPL(torture_onoff_init); 401 402 /* 403 * Clean up after online/offline testing. 404 */ 405 static void torture_onoff_cleanup(void) 406 { 407 #ifdef CONFIG_HOTPLUG_CPU 408 if (onoff_task == NULL) 409 return; 410 VERBOSE_TOROUT_STRING("Stopping torture_onoff task"); 411 kthread_stop(onoff_task); 412 onoff_task = NULL; 413 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 414 } 415 416 /* 417 * Print online/offline testing statistics. 418 */ 419 void torture_onoff_stats(void) 420 { 421 #ifdef CONFIG_HOTPLUG_CPU 422 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", 423 n_online_successes, n_online_attempts, 424 n_offline_successes, n_offline_attempts, 425 min_online, max_online, 426 min_offline, max_offline, 427 sum_online, sum_offline, HZ); 428 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 429 } 430 EXPORT_SYMBOL_GPL(torture_onoff_stats); 431 432 /* 433 * Were all the online/offline operations successful? 434 */ 435 bool torture_onoff_failures(void) 436 { 437 #ifdef CONFIG_HOTPLUG_CPU 438 return n_online_successes != n_online_attempts || 439 n_offline_successes != n_offline_attempts; 440 #else /* #ifdef CONFIG_HOTPLUG_CPU */ 441 return false; 442 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ 443 } 444 EXPORT_SYMBOL_GPL(torture_onoff_failures); 445 446 #define TORTURE_RANDOM_MULT 39916801 /* prime */ 447 #define TORTURE_RANDOM_ADD 479001701 /* prime */ 448 #define TORTURE_RANDOM_REFRESH 10000 449 450 /* 451 * Crude but fast random-number generator. Uses a linear congruential 452 * generator, with occasional help from cpu_clock(). 453 */ 454 unsigned long 455 torture_random(struct torture_random_state *trsp) 456 { 457 if (--trsp->trs_count < 0) { 458 trsp->trs_state += (unsigned long)local_clock() + raw_smp_processor_id(); 459 trsp->trs_count = TORTURE_RANDOM_REFRESH; 460 } 461 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT + 462 TORTURE_RANDOM_ADD; 463 return swahw32(trsp->trs_state); 464 } 465 EXPORT_SYMBOL_GPL(torture_random); 466 467 /* 468 * Variables for shuffling. The idea is to ensure that each CPU stays 469 * idle for an extended period to test interactions with dyntick idle, 470 * as well as interactions with any per-CPU variables. 471 */ 472 struct shuffle_task { 473 struct list_head st_l; 474 struct task_struct *st_t; 475 }; 476 477 static long shuffle_interval; /* In jiffies. */ 478 static struct task_struct *shuffler_task; 479 static cpumask_var_t shuffle_tmp_mask; 480 static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */ 481 static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list); 482 static DEFINE_MUTEX(shuffle_task_mutex); 483 484 /* 485 * Register a task to be shuffled. If there is no memory, just splat 486 * and don't bother registering. 487 */ 488 void torture_shuffle_task_register(struct task_struct *tp) 489 { 490 struct shuffle_task *stp; 491 492 if (WARN_ON_ONCE(tp == NULL)) 493 return; 494 stp = kmalloc(sizeof(*stp), GFP_KERNEL); 495 if (WARN_ON_ONCE(stp == NULL)) 496 return; 497 stp->st_t = tp; 498 mutex_lock(&shuffle_task_mutex); 499 list_add(&stp->st_l, &shuffle_task_list); 500 mutex_unlock(&shuffle_task_mutex); 501 } 502 EXPORT_SYMBOL_GPL(torture_shuffle_task_register); 503 504 /* 505 * Unregister all tasks, for example, at the end of the torture run. 506 */ 507 static void torture_shuffle_task_unregister_all(void) 508 { 509 struct shuffle_task *stp; 510 struct shuffle_task *p; 511 512 mutex_lock(&shuffle_task_mutex); 513 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) { 514 list_del(&stp->st_l); 515 kfree(stp); 516 } 517 mutex_unlock(&shuffle_task_mutex); 518 } 519 520 /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle. 521 * A special case is when shuffle_idle_cpu = -1, in which case we allow 522 * the tasks to run on all CPUs. 523 */ 524 static void torture_shuffle_tasks(struct torture_random_state *trp) 525 { 526 struct shuffle_task *stp; 527 528 cpumask_setall(shuffle_tmp_mask); 529 cpus_read_lock(); 530 531 /* No point in shuffling if there is only one online CPU (ex: UP) */ 532 if (num_online_cpus() == 1) { 533 cpus_read_unlock(); 534 return; 535 } 536 537 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */ 538 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask); 539 if (shuffle_idle_cpu >= nr_cpu_ids) 540 shuffle_idle_cpu = -1; 541 else 542 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask); 543 544 mutex_lock(&shuffle_task_mutex); 545 list_for_each_entry(stp, &shuffle_task_list, st_l) { 546 if (!random_shuffle || torture_random(trp) & 0x1) 547 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask); 548 } 549 mutex_unlock(&shuffle_task_mutex); 550 551 cpus_read_unlock(); 552 } 553 554 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the 555 * system to become idle at a time and cut off its timer ticks. This is meant 556 * to test the support for such tickless idle CPU in RCU. 557 */ 558 static int torture_shuffle(void *arg) 559 { 560 DEFINE_TORTURE_RANDOM(rand); 561 562 VERBOSE_TOROUT_STRING("torture_shuffle task started"); 563 do { 564 torture_hrtimeout_jiffies(shuffle_interval, &rand); 565 torture_shuffle_tasks(&rand); 566 torture_shutdown_absorb("torture_shuffle"); 567 } while (!torture_must_stop()); 568 torture_kthread_stopping("torture_shuffle"); 569 return 0; 570 } 571 572 /* 573 * Start the shuffler, with shuffint in jiffies. 574 */ 575 int torture_shuffle_init(long shuffint) 576 { 577 shuffle_interval = shuffint; 578 579 shuffle_idle_cpu = -1; 580 581 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) { 582 TOROUT_ERRSTRING("Failed to alloc mask"); 583 return -ENOMEM; 584 } 585 586 /* Create the shuffler thread */ 587 return torture_create_kthread(torture_shuffle, NULL, shuffler_task); 588 } 589 EXPORT_SYMBOL_GPL(torture_shuffle_init); 590 591 /* 592 * Stop the shuffling. 593 */ 594 static void torture_shuffle_cleanup(void) 595 { 596 torture_shuffle_task_unregister_all(); 597 if (shuffler_task) { 598 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task"); 599 kthread_stop(shuffler_task); 600 free_cpumask_var(shuffle_tmp_mask); 601 } 602 shuffler_task = NULL; 603 } 604 605 /* 606 * Variables for auto-shutdown. This allows "lights out" torture runs 607 * to be fully scripted. 608 */ 609 static struct task_struct *shutdown_task; 610 static ktime_t shutdown_time; /* time to system shutdown. */ 611 static void (*torture_shutdown_hook)(void); 612 613 /* 614 * Absorb kthreads into a kernel function that won't return, so that 615 * they won't ever access module text or data again. 616 */ 617 void torture_shutdown_absorb(const char *title) 618 { 619 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { 620 pr_notice("torture thread %s parking due to system shutdown\n", 621 title); 622 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); 623 } 624 } 625 EXPORT_SYMBOL_GPL(torture_shutdown_absorb); 626 627 /* 628 * Cause the torture test to shutdown the system after the test has 629 * run for the time specified by the shutdown_secs parameter. 630 */ 631 static int torture_shutdown(void *arg) 632 { 633 ktime_t ktime_snap; 634 635 VERBOSE_TOROUT_STRING("torture_shutdown task started"); 636 ktime_snap = ktime_get(); 637 while (ktime_before(ktime_snap, shutdown_time) && 638 !torture_must_stop()) { 639 if (verbose) 640 pr_alert("%s" TORTURE_FLAG 641 "torture_shutdown task: %llu ms remaining\n", 642 torture_type, 643 ktime_ms_delta(shutdown_time, ktime_snap)); 644 set_current_state(TASK_INTERRUPTIBLE); 645 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS); 646 ktime_snap = ktime_get(); 647 } 648 if (torture_must_stop()) { 649 torture_kthread_stopping("torture_shutdown"); 650 return 0; 651 } 652 653 /* OK, shut down the system. */ 654 655 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system"); 656 shutdown_task = NULL; /* Avoid self-kill deadlock. */ 657 if (torture_shutdown_hook) 658 torture_shutdown_hook(); 659 else 660 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping."); 661 if (ftrace_dump_at_shutdown) 662 rcu_ftrace_dump(DUMP_ALL); 663 kernel_power_off(); /* Shut down the system. */ 664 return 0; 665 } 666 667 /* 668 * Start up the shutdown task. 669 */ 670 int torture_shutdown_init(int ssecs, void (*cleanup)(void)) 671 { 672 torture_shutdown_hook = cleanup; 673 if (ssecs > 0) { 674 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0)); 675 return torture_create_kthread(torture_shutdown, NULL, 676 shutdown_task); 677 } 678 return 0; 679 } 680 EXPORT_SYMBOL_GPL(torture_shutdown_init); 681 682 /* 683 * Detect and respond to a system shutdown. 684 */ 685 static int torture_shutdown_notify(struct notifier_block *unused1, 686 unsigned long unused2, void *unused3) 687 { 688 mutex_lock(&fullstop_mutex); 689 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) { 690 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected"); 691 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN); 692 } else { 693 pr_warn("Concurrent rmmod and shutdown illegal!\n"); 694 } 695 mutex_unlock(&fullstop_mutex); 696 return NOTIFY_DONE; 697 } 698 699 static struct notifier_block torture_shutdown_nb = { 700 .notifier_call = torture_shutdown_notify, 701 }; 702 703 /* 704 * Shut down the shutdown task. Say what??? Heh! This can happen if 705 * the torture module gets an rmmod before the shutdown time arrives. ;-) 706 */ 707 static void torture_shutdown_cleanup(void) 708 { 709 unregister_reboot_notifier(&torture_shutdown_nb); 710 if (shutdown_task != NULL) { 711 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task"); 712 kthread_stop(shutdown_task); 713 } 714 shutdown_task = NULL; 715 } 716 717 /* 718 * Variables for stuttering, which means to periodically pause and 719 * restart testing in order to catch bugs that appear when load is 720 * suddenly applied to or removed from the system. 721 */ 722 static struct task_struct *stutter_task; 723 static ktime_t stutter_till_abs_time; 724 static int stutter; 725 static int stutter_gap; 726 727 /* 728 * Block until the stutter interval ends. This must be called periodically 729 * by all running kthreads that need to be subject to stuttering. 730 */ 731 bool stutter_wait(const char *title) 732 { 733 bool ret = false; 734 ktime_t till_ns; 735 736 cond_resched_tasks_rcu_qs(); 737 till_ns = READ_ONCE(stutter_till_abs_time); 738 if (till_ns && ktime_before(ktime_get(), till_ns)) { 739 torture_hrtimeout_ns(till_ns, 0, HRTIMER_MODE_ABS, NULL); 740 ret = true; 741 } 742 torture_shutdown_absorb(title); 743 return ret; 744 } 745 EXPORT_SYMBOL_GPL(stutter_wait); 746 747 /* 748 * Cause the torture test to "stutter", starting and stopping all 749 * threads periodically. 750 */ 751 static int torture_stutter(void *arg) 752 { 753 ktime_t till_ns; 754 755 VERBOSE_TOROUT_STRING("torture_stutter task started"); 756 do { 757 if (!torture_must_stop() && stutter > 1) { 758 till_ns = ktime_add_ns(ktime_get(), 759 jiffies_to_nsecs(stutter)); 760 WRITE_ONCE(stutter_till_abs_time, till_ns); 761 torture_hrtimeout_jiffies(stutter - 1, NULL); 762 } 763 if (!torture_must_stop()) 764 torture_hrtimeout_jiffies(stutter_gap, NULL); 765 torture_shutdown_absorb("torture_stutter"); 766 } while (!torture_must_stop()); 767 torture_kthread_stopping("torture_stutter"); 768 return 0; 769 } 770 771 /* 772 * Initialize and kick off the torture_stutter kthread. 773 */ 774 int torture_stutter_init(const int s, const int sgap) 775 { 776 stutter = s; 777 stutter_gap = sgap; 778 return torture_create_kthread(torture_stutter, NULL, stutter_task); 779 } 780 EXPORT_SYMBOL_GPL(torture_stutter_init); 781 782 /* 783 * Cleanup after the torture_stutter kthread. 784 */ 785 static void torture_stutter_cleanup(void) 786 { 787 if (!stutter_task) 788 return; 789 VERBOSE_TOROUT_STRING("Stopping torture_stutter task"); 790 kthread_stop(stutter_task); 791 stutter_task = NULL; 792 } 793 794 static void 795 torture_print_module_parms(void) 796 { 797 pr_alert("torture module --- %s: disable_onoff_at_boot=%d ftrace_dump_at_shutdown=%d verbose_sleep_frequency=%d verbose_sleep_duration=%d random_shuffle=%d\n", 798 torture_type, disable_onoff_at_boot, ftrace_dump_at_shutdown, verbose_sleep_frequency, verbose_sleep_duration, random_shuffle); 799 } 800 801 /* 802 * Initialize torture module. Please note that this is -not- invoked via 803 * the usual module_init() mechanism, but rather by an explicit call from 804 * the client torture module. This call must be paired with a later 805 * torture_init_end(). 806 * 807 * The runnable parameter points to a flag that controls whether or not 808 * the test is currently runnable. If there is no such flag, pass in NULL. 809 */ 810 bool torture_init_begin(char *ttype, int v) 811 { 812 mutex_lock(&fullstop_mutex); 813 if (torture_type != NULL) { 814 pr_alert("%s: Refusing %s init: %s running.\n", 815 __func__, ttype, torture_type); 816 pr_alert("%s: One torture test at a time!\n", __func__); 817 mutex_unlock(&fullstop_mutex); 818 return false; 819 } 820 torture_type = ttype; 821 verbose = v; 822 fullstop = FULLSTOP_DONTSTOP; 823 torture_print_module_parms(); 824 return true; 825 } 826 EXPORT_SYMBOL_GPL(torture_init_begin); 827 828 /* 829 * Tell the torture module that initialization is complete. 830 */ 831 void torture_init_end(void) 832 { 833 mutex_unlock(&fullstop_mutex); 834 register_reboot_notifier(&torture_shutdown_nb); 835 } 836 EXPORT_SYMBOL_GPL(torture_init_end); 837 838 /* 839 * Clean up torture module. Please note that this is -not- invoked via 840 * the usual module_exit() mechanism, but rather by an explicit call from 841 * the client torture module. Returns true if a race with system shutdown 842 * is detected, otherwise, all kthreads started by functions in this file 843 * will be shut down. 844 * 845 * This must be called before the caller starts shutting down its own 846 * kthreads. 847 * 848 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired, 849 * in order to correctly perform the cleanup. They are separated because 850 * threads can still need to reference the torture_type type, thus nullify 851 * only after completing all other relevant calls. 852 */ 853 bool torture_cleanup_begin(void) 854 { 855 mutex_lock(&fullstop_mutex); 856 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { 857 pr_warn("Concurrent rmmod and shutdown illegal!\n"); 858 mutex_unlock(&fullstop_mutex); 859 schedule_timeout_uninterruptible(10); 860 return true; 861 } 862 WRITE_ONCE(fullstop, FULLSTOP_RMMOD); 863 mutex_unlock(&fullstop_mutex); 864 torture_shutdown_cleanup(); 865 torture_shuffle_cleanup(); 866 torture_stutter_cleanup(); 867 torture_onoff_cleanup(); 868 return false; 869 } 870 EXPORT_SYMBOL_GPL(torture_cleanup_begin); 871 872 void torture_cleanup_end(void) 873 { 874 mutex_lock(&fullstop_mutex); 875 torture_type = NULL; 876 mutex_unlock(&fullstop_mutex); 877 } 878 EXPORT_SYMBOL_GPL(torture_cleanup_end); 879 880 /* 881 * Is it time for the current torture test to stop? 882 */ 883 bool torture_must_stop(void) 884 { 885 return torture_must_stop_irq() || kthread_should_stop(); 886 } 887 EXPORT_SYMBOL_GPL(torture_must_stop); 888 889 /* 890 * Is it time for the current torture test to stop? This is the irq-safe 891 * version, hence no check for kthread_should_stop(). 892 */ 893 bool torture_must_stop_irq(void) 894 { 895 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP; 896 } 897 EXPORT_SYMBOL_GPL(torture_must_stop_irq); 898 899 /* 900 * Each kthread must wait for kthread_should_stop() before returning from 901 * its top-level function, otherwise segfaults ensue. This function 902 * prints a "stopping" message and waits for kthread_should_stop(), and 903 * should be called from all torture kthreads immediately prior to 904 * returning. 905 */ 906 void torture_kthread_stopping(char *title) 907 { 908 char buf[128]; 909 910 snprintf(buf, sizeof(buf), "%s is stopping", title); 911 VERBOSE_TOROUT_STRING(buf); 912 while (!kthread_should_stop()) { 913 torture_shutdown_absorb(title); 914 schedule_timeout_uninterruptible(HZ / 20); 915 } 916 } 917 EXPORT_SYMBOL_GPL(torture_kthread_stopping); 918 919 /* 920 * Create a generic torture kthread that is immediately runnable. If you 921 * need the kthread to be stopped so that you can do something to it before 922 * it starts, you will need to open-code your own. 923 */ 924 int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m, 925 char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp)) 926 { 927 int ret = 0; 928 929 VERBOSE_TOROUT_STRING(m); 930 *tp = kthread_create(fn, arg, "%s", s); 931 if (IS_ERR(*tp)) { 932 ret = PTR_ERR(*tp); 933 TOROUT_ERRSTRING(f); 934 *tp = NULL; 935 return ret; 936 } 937 938 if (cbf) 939 cbf(*tp); 940 941 wake_up_process(*tp); // Process is sleeping, so ordering provided. 942 torture_shuffle_task_register(*tp); 943 return ret; 944 } 945 EXPORT_SYMBOL_GPL(_torture_create_kthread); 946 947 /* 948 * Stop a generic kthread, emitting a message. 949 */ 950 void _torture_stop_kthread(char *m, struct task_struct **tp) 951 { 952 if (*tp == NULL) 953 return; 954 VERBOSE_TOROUT_STRING(m); 955 kthread_stop(*tp); 956 *tp = NULL; 957 } 958 EXPORT_SYMBOL_GPL(_torture_stop_kthread); 959