1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/kernel/panic.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 */ 7 8 /* 9 * This function is used through-out the kernel (including mm and fs) 10 * to indicate a major problem. 11 */ 12 #include <linux/debug_locks.h> 13 #include <linux/sched/debug.h> 14 #include <linux/interrupt.h> 15 #include <linux/kgdb.h> 16 #include <linux/kmsg_dump.h> 17 #include <linux/kallsyms.h> 18 #include <linux/notifier.h> 19 #include <linux/vt_kern.h> 20 #include <linux/module.h> 21 #include <linux/random.h> 22 #include <linux/ftrace.h> 23 #include <linux/reboot.h> 24 #include <linux/delay.h> 25 #include <linux/kexec.h> 26 #include <linux/panic_notifier.h> 27 #include <linux/sched.h> 28 #include <linux/string_helpers.h> 29 #include <linux/sysrq.h> 30 #include <linux/init.h> 31 #include <linux/nmi.h> 32 #include <linux/console.h> 33 #include <linux/bug.h> 34 #include <linux/ratelimit.h> 35 #include <linux/debugfs.h> 36 #include <linux/sysfs.h> 37 #include <linux/context_tracking.h> 38 #include <trace/events/error_report.h> 39 #include <asm/sections.h> 40 41 #define PANIC_TIMER_STEP 100 42 #define PANIC_BLINK_SPD 18 43 44 #ifdef CONFIG_SMP 45 /* 46 * Should we dump all CPUs backtraces in an oops event? 47 * Defaults to 0, can be changed via sysctl. 48 */ 49 static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; 50 #else 51 #define sysctl_oops_all_cpu_backtrace 0 52 #endif /* CONFIG_SMP */ 53 54 int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; 55 static unsigned long tainted_mask = 56 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; 57 static int pause_on_oops; 58 static int pause_on_oops_flag; 59 static DEFINE_SPINLOCK(pause_on_oops_lock); 60 bool crash_kexec_post_notifiers; 61 int panic_on_warn __read_mostly; 62 unsigned long panic_on_taint; 63 bool panic_on_taint_nousertaint = false; 64 static unsigned int warn_limit __read_mostly; 65 66 int panic_timeout = CONFIG_PANIC_TIMEOUT; 67 EXPORT_SYMBOL_GPL(panic_timeout); 68 69 #define PANIC_PRINT_TASK_INFO 0x00000001 70 #define PANIC_PRINT_MEM_INFO 0x00000002 71 #define PANIC_PRINT_TIMER_INFO 0x00000004 72 #define PANIC_PRINT_LOCK_INFO 0x00000008 73 #define PANIC_PRINT_FTRACE_INFO 0x00000010 74 #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 75 #define PANIC_PRINT_ALL_CPU_BT 0x00000040 76 #define PANIC_PRINT_BLOCKED_TASKS 0x00000080 77 unsigned long panic_print; 78 79 ATOMIC_NOTIFIER_HEAD(panic_notifier_list); 80 81 EXPORT_SYMBOL(panic_notifier_list); 82 83 #ifdef CONFIG_SYSCTL 84 static struct ctl_table kern_panic_table[] = { 85 #ifdef CONFIG_SMP 86 { 87 .procname = "oops_all_cpu_backtrace", 88 .data = &sysctl_oops_all_cpu_backtrace, 89 .maxlen = sizeof(int), 90 .mode = 0644, 91 .proc_handler = proc_dointvec_minmax, 92 .extra1 = SYSCTL_ZERO, 93 .extra2 = SYSCTL_ONE, 94 }, 95 #endif 96 { 97 .procname = "warn_limit", 98 .data = &warn_limit, 99 .maxlen = sizeof(warn_limit), 100 .mode = 0644, 101 .proc_handler = proc_douintvec, 102 }, 103 }; 104 105 static __init int kernel_panic_sysctls_init(void) 106 { 107 register_sysctl_init("kernel", kern_panic_table); 108 return 0; 109 } 110 late_initcall(kernel_panic_sysctls_init); 111 #endif 112 113 static atomic_t warn_count = ATOMIC_INIT(0); 114 115 #ifdef CONFIG_SYSFS 116 static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr, 117 char *page) 118 { 119 return sysfs_emit(page, "%d\n", atomic_read(&warn_count)); 120 } 121 122 static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count); 123 124 static __init int kernel_panic_sysfs_init(void) 125 { 126 sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL); 127 return 0; 128 } 129 late_initcall(kernel_panic_sysfs_init); 130 #endif 131 132 static long no_blink(int state) 133 { 134 return 0; 135 } 136 137 /* Returns how long it waited in ms */ 138 long (*panic_blink)(int state); 139 EXPORT_SYMBOL(panic_blink); 140 141 /* 142 * Stop ourself in panic -- architecture code may override this 143 */ 144 void __weak __noreturn panic_smp_self_stop(void) 145 { 146 while (1) 147 cpu_relax(); 148 } 149 150 /* 151 * Stop ourselves in NMI context if another CPU has already panicked. Arch code 152 * may override this to prepare for crash dumping, e.g. save regs info. 153 */ 154 void __weak __noreturn nmi_panic_self_stop(struct pt_regs *regs) 155 { 156 panic_smp_self_stop(); 157 } 158 159 /* 160 * Stop other CPUs in panic. Architecture dependent code may override this 161 * with more suitable version. For example, if the architecture supports 162 * crash dump, it should save registers of each stopped CPU and disable 163 * per-CPU features such as virtualization extensions. 164 */ 165 void __weak crash_smp_send_stop(void) 166 { 167 static int cpus_stopped; 168 169 /* 170 * This function can be called twice in panic path, but obviously 171 * we execute this only once. 172 */ 173 if (cpus_stopped) 174 return; 175 176 /* 177 * Note smp_send_stop is the usual smp shutdown function, which 178 * unfortunately means it may not be hardened to work in a panic 179 * situation. 180 */ 181 smp_send_stop(); 182 cpus_stopped = 1; 183 } 184 185 atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); 186 187 /* 188 * A variant of panic() called from NMI context. We return if we've already 189 * panicked on this CPU. If another CPU already panicked, loop in 190 * nmi_panic_self_stop() which can provide architecture dependent code such 191 * as saving register state for crash dump. 192 */ 193 void nmi_panic(struct pt_regs *regs, const char *msg) 194 { 195 int old_cpu, this_cpu; 196 197 old_cpu = PANIC_CPU_INVALID; 198 this_cpu = raw_smp_processor_id(); 199 200 /* atomic_try_cmpxchg updates old_cpu on failure */ 201 if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) 202 panic("%s", msg); 203 else if (old_cpu != this_cpu) 204 nmi_panic_self_stop(regs); 205 } 206 EXPORT_SYMBOL(nmi_panic); 207 208 static void panic_print_sys_info(bool console_flush) 209 { 210 if (console_flush) { 211 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) 212 console_flush_on_panic(CONSOLE_REPLAY_ALL); 213 return; 214 } 215 216 if (panic_print & PANIC_PRINT_TASK_INFO) 217 show_state(); 218 219 if (panic_print & PANIC_PRINT_MEM_INFO) 220 show_mem(); 221 222 if (panic_print & PANIC_PRINT_TIMER_INFO) 223 sysrq_timer_list_show(); 224 225 if (panic_print & PANIC_PRINT_LOCK_INFO) 226 debug_show_all_locks(); 227 228 if (panic_print & PANIC_PRINT_FTRACE_INFO) 229 ftrace_dump(DUMP_ALL); 230 231 if (panic_print & PANIC_PRINT_BLOCKED_TASKS) 232 show_state_filter(TASK_UNINTERRUPTIBLE); 233 } 234 235 void check_panic_on_warn(const char *origin) 236 { 237 unsigned int limit; 238 239 if (panic_on_warn) 240 panic("%s: panic_on_warn set ...\n", origin); 241 242 limit = READ_ONCE(warn_limit); 243 if (atomic_inc_return(&warn_count) >= limit && limit) 244 panic("%s: system warned too often (kernel.warn_limit is %d)", 245 origin, limit); 246 } 247 248 /* 249 * Helper that triggers the NMI backtrace (if set in panic_print) 250 * and then performs the secondary CPUs shutdown - we cannot have 251 * the NMI backtrace after the CPUs are off! 252 */ 253 static void panic_other_cpus_shutdown(bool crash_kexec) 254 { 255 if (panic_print & PANIC_PRINT_ALL_CPU_BT) 256 trigger_all_cpu_backtrace(); 257 258 /* 259 * Note that smp_send_stop() is the usual SMP shutdown function, 260 * which unfortunately may not be hardened to work in a panic 261 * situation. If we want to do crash dump after notifier calls 262 * and kmsg_dump, we will need architecture dependent extra 263 * bits in addition to stopping other CPUs, hence we rely on 264 * crash_smp_send_stop() for that. 265 */ 266 if (!crash_kexec) 267 smp_send_stop(); 268 else 269 crash_smp_send_stop(); 270 } 271 272 /** 273 * panic - halt the system 274 * @fmt: The text string to print 275 * 276 * Display a message, then perform cleanups. 277 * 278 * This function never returns. 279 */ 280 void panic(const char *fmt, ...) 281 { 282 static char buf[1024]; 283 va_list args; 284 long i, i_next = 0, len; 285 int state = 0; 286 int old_cpu, this_cpu; 287 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; 288 289 if (panic_on_warn) { 290 /* 291 * This thread may hit another WARN() in the panic path. 292 * Resetting this prevents additional WARN() from panicking the 293 * system on this thread. Other threads are blocked by the 294 * panic_mutex in panic(). 295 */ 296 panic_on_warn = 0; 297 } 298 299 /* 300 * Disable local interrupts. This will prevent panic_smp_self_stop 301 * from deadlocking the first cpu that invokes the panic, since 302 * there is nothing to prevent an interrupt handler (that runs 303 * after setting panic_cpu) from invoking panic() again. 304 */ 305 local_irq_disable(); 306 preempt_disable_notrace(); 307 308 /* 309 * It's possible to come here directly from a panic-assertion and 310 * not have preempt disabled. Some functions called from here want 311 * preempt to be disabled. No point enabling it later though... 312 * 313 * Only one CPU is allowed to execute the panic code from here. For 314 * multiple parallel invocations of panic, all other CPUs either 315 * stop themself or will wait until they are stopped by the 1st CPU 316 * with smp_send_stop(). 317 * 318 * cmpxchg success means this is the 1st CPU which comes here, 319 * so go ahead. 320 * `old_cpu == this_cpu' means we came from nmi_panic() which sets 321 * panic_cpu to this CPU. In this case, this is also the 1st CPU. 322 */ 323 old_cpu = PANIC_CPU_INVALID; 324 this_cpu = raw_smp_processor_id(); 325 326 /* atomic_try_cmpxchg updates old_cpu on failure */ 327 if (atomic_try_cmpxchg(&panic_cpu, &old_cpu, this_cpu)) { 328 /* go ahead */ 329 } else if (old_cpu != this_cpu) 330 panic_smp_self_stop(); 331 332 console_verbose(); 333 bust_spinlocks(1); 334 va_start(args, fmt); 335 len = vscnprintf(buf, sizeof(buf), fmt, args); 336 va_end(args); 337 338 if (len && buf[len - 1] == '\n') 339 buf[len - 1] = '\0'; 340 341 pr_emerg("Kernel panic - not syncing: %s\n", buf); 342 #ifdef CONFIG_DEBUG_BUGVERBOSE 343 /* 344 * Avoid nested stack-dumping if a panic occurs during oops processing 345 */ 346 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) 347 dump_stack(); 348 #endif 349 350 /* 351 * If kgdb is enabled, give it a chance to run before we stop all 352 * the other CPUs or else we won't be able to debug processes left 353 * running on them. 354 */ 355 kgdb_panic(buf); 356 357 /* 358 * If we have crashed and we have a crash kernel loaded let it handle 359 * everything else. 360 * If we want to run this after calling panic_notifiers, pass 361 * the "crash_kexec_post_notifiers" option to the kernel. 362 * 363 * Bypass the panic_cpu check and call __crash_kexec directly. 364 */ 365 if (!_crash_kexec_post_notifiers) 366 __crash_kexec(NULL); 367 368 panic_other_cpus_shutdown(_crash_kexec_post_notifiers); 369 370 /* 371 * Run any panic handlers, including those that might need to 372 * add information to the kmsg dump output. 373 */ 374 atomic_notifier_call_chain(&panic_notifier_list, 0, buf); 375 376 panic_print_sys_info(false); 377 378 kmsg_dump(KMSG_DUMP_PANIC); 379 380 /* 381 * If you doubt kdump always works fine in any situation, 382 * "crash_kexec_post_notifiers" offers you a chance to run 383 * panic_notifiers and dumping kmsg before kdump. 384 * Note: since some panic_notifiers can make crashed kernel 385 * more unstable, it can increase risks of the kdump failure too. 386 * 387 * Bypass the panic_cpu check and call __crash_kexec directly. 388 */ 389 if (_crash_kexec_post_notifiers) 390 __crash_kexec(NULL); 391 392 console_unblank(); 393 394 /* 395 * We may have ended up stopping the CPU holding the lock (in 396 * smp_send_stop()) while still having some valuable data in the console 397 * buffer. Try to acquire the lock then release it regardless of the 398 * result. The release will also print the buffers out. Locks debug 399 * should be disabled to avoid reporting bad unlock balance when 400 * panic() is not being callled from OOPS. 401 */ 402 debug_locks_off(); 403 console_flush_on_panic(CONSOLE_FLUSH_PENDING); 404 405 panic_print_sys_info(true); 406 407 if (!panic_blink) 408 panic_blink = no_blink; 409 410 if (panic_timeout > 0) { 411 /* 412 * Delay timeout seconds before rebooting the machine. 413 * We can't use the "normal" timers since we just panicked. 414 */ 415 pr_emerg("Rebooting in %d seconds..\n", panic_timeout); 416 417 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { 418 touch_nmi_watchdog(); 419 if (i >= i_next) { 420 i += panic_blink(state ^= 1); 421 i_next = i + 3600 / PANIC_BLINK_SPD; 422 } 423 mdelay(PANIC_TIMER_STEP); 424 } 425 } 426 if (panic_timeout != 0) { 427 /* 428 * This will not be a clean reboot, with everything 429 * shutting down. But if there is a chance of 430 * rebooting the system it will be rebooted. 431 */ 432 if (panic_reboot_mode != REBOOT_UNDEFINED) 433 reboot_mode = panic_reboot_mode; 434 emergency_restart(); 435 } 436 #ifdef __sparc__ 437 { 438 extern int stop_a_enabled; 439 /* Make sure the user can actually press Stop-A (L1-A) */ 440 stop_a_enabled = 1; 441 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" 442 "twice on console to return to the boot prom\n"); 443 } 444 #endif 445 #if defined(CONFIG_S390) 446 disabled_wait(); 447 #endif 448 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); 449 450 /* Do not scroll important messages printed above */ 451 suppress_printk = 1; 452 453 /* 454 * The final messages may not have been printed if in a context that 455 * defers printing (such as NMI) and irq_work is not available. 456 * Explicitly flush the kernel log buffer one last time. 457 */ 458 console_flush_on_panic(CONSOLE_FLUSH_PENDING); 459 460 local_irq_enable(); 461 for (i = 0; ; i += PANIC_TIMER_STEP) { 462 touch_softlockup_watchdog(); 463 if (i >= i_next) { 464 i += panic_blink(state ^= 1); 465 i_next = i + 3600 / PANIC_BLINK_SPD; 466 } 467 mdelay(PANIC_TIMER_STEP); 468 } 469 } 470 471 EXPORT_SYMBOL(panic); 472 473 /* 474 * TAINT_FORCED_RMMOD could be a per-module flag but the module 475 * is being removed anyway. 476 */ 477 const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { 478 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, 479 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, 480 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, 481 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, 482 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, 483 [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, 484 [ TAINT_USER ] = { 'U', ' ', false }, 485 [ TAINT_DIE ] = { 'D', ' ', false }, 486 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, 487 [ TAINT_WARN ] = { 'W', ' ', false }, 488 [ TAINT_CRAP ] = { 'C', ' ', true }, 489 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, 490 [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, 491 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, 492 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, 493 [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, 494 [ TAINT_AUX ] = { 'X', ' ', true }, 495 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, 496 [ TAINT_TEST ] = { 'N', ' ', true }, 497 }; 498 499 /** 500 * print_tainted - return a string to represent the kernel taint state. 501 * 502 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst 503 * 504 * The string is overwritten by the next call to print_tainted(), 505 * but is always NULL terminated. 506 */ 507 const char *print_tainted(void) 508 { 509 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; 510 511 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); 512 513 if (tainted_mask) { 514 char *s; 515 int i; 516 517 s = buf + sprintf(buf, "Tainted: "); 518 for (i = 0; i < TAINT_FLAGS_COUNT; i++) { 519 const struct taint_flag *t = &taint_flags[i]; 520 *s++ = test_bit(i, &tainted_mask) ? 521 t->c_true : t->c_false; 522 } 523 *s = 0; 524 } else 525 snprintf(buf, sizeof(buf), "Not tainted"); 526 527 return buf; 528 } 529 530 int test_taint(unsigned flag) 531 { 532 return test_bit(flag, &tainted_mask); 533 } 534 EXPORT_SYMBOL(test_taint); 535 536 unsigned long get_taint(void) 537 { 538 return tainted_mask; 539 } 540 541 /** 542 * add_taint: add a taint flag if not already set. 543 * @flag: one of the TAINT_* constants. 544 * @lockdep_ok: whether lock debugging is still OK. 545 * 546 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for 547 * some notewortht-but-not-corrupting cases, it can be set to true. 548 */ 549 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) 550 { 551 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) 552 pr_warn("Disabling lock debugging due to kernel taint\n"); 553 554 set_bit(flag, &tainted_mask); 555 556 if (tainted_mask & panic_on_taint) { 557 panic_on_taint = 0; 558 panic("panic_on_taint set ..."); 559 } 560 } 561 EXPORT_SYMBOL(add_taint); 562 563 static void spin_msec(int msecs) 564 { 565 int i; 566 567 for (i = 0; i < msecs; i++) { 568 touch_nmi_watchdog(); 569 mdelay(1); 570 } 571 } 572 573 /* 574 * It just happens that oops_enter() and oops_exit() are identically 575 * implemented... 576 */ 577 static void do_oops_enter_exit(void) 578 { 579 unsigned long flags; 580 static int spin_counter; 581 582 if (!pause_on_oops) 583 return; 584 585 spin_lock_irqsave(&pause_on_oops_lock, flags); 586 if (pause_on_oops_flag == 0) { 587 /* This CPU may now print the oops message */ 588 pause_on_oops_flag = 1; 589 } else { 590 /* We need to stall this CPU */ 591 if (!spin_counter) { 592 /* This CPU gets to do the counting */ 593 spin_counter = pause_on_oops; 594 do { 595 spin_unlock(&pause_on_oops_lock); 596 spin_msec(MSEC_PER_SEC); 597 spin_lock(&pause_on_oops_lock); 598 } while (--spin_counter); 599 pause_on_oops_flag = 0; 600 } else { 601 /* This CPU waits for a different one */ 602 while (spin_counter) { 603 spin_unlock(&pause_on_oops_lock); 604 spin_msec(1); 605 spin_lock(&pause_on_oops_lock); 606 } 607 } 608 } 609 spin_unlock_irqrestore(&pause_on_oops_lock, flags); 610 } 611 612 /* 613 * Return true if the calling CPU is allowed to print oops-related info. 614 * This is a bit racy.. 615 */ 616 bool oops_may_print(void) 617 { 618 return pause_on_oops_flag == 0; 619 } 620 621 /* 622 * Called when the architecture enters its oops handler, before it prints 623 * anything. If this is the first CPU to oops, and it's oopsing the first 624 * time then let it proceed. 625 * 626 * This is all enabled by the pause_on_oops kernel boot option. We do all 627 * this to ensure that oopses don't scroll off the screen. It has the 628 * side-effect of preventing later-oopsing CPUs from mucking up the display, 629 * too. 630 * 631 * It turns out that the CPU which is allowed to print ends up pausing for 632 * the right duration, whereas all the other CPUs pause for twice as long: 633 * once in oops_enter(), once in oops_exit(). 634 */ 635 void oops_enter(void) 636 { 637 tracing_off(); 638 /* can't trust the integrity of the kernel anymore: */ 639 debug_locks_off(); 640 do_oops_enter_exit(); 641 642 if (sysctl_oops_all_cpu_backtrace) 643 trigger_all_cpu_backtrace(); 644 } 645 646 static void print_oops_end_marker(void) 647 { 648 pr_warn("---[ end trace %016llx ]---\n", 0ULL); 649 } 650 651 /* 652 * Called when the architecture exits its oops handler, after printing 653 * everything. 654 */ 655 void oops_exit(void) 656 { 657 do_oops_enter_exit(); 658 print_oops_end_marker(); 659 kmsg_dump(KMSG_DUMP_OOPS); 660 } 661 662 struct warn_args { 663 const char *fmt; 664 va_list args; 665 }; 666 667 void __warn(const char *file, int line, void *caller, unsigned taint, 668 struct pt_regs *regs, struct warn_args *args) 669 { 670 disable_trace_on_warning(); 671 672 if (file) 673 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", 674 raw_smp_processor_id(), current->pid, file, line, 675 caller); 676 else 677 pr_warn("WARNING: CPU: %d PID: %d at %pS\n", 678 raw_smp_processor_id(), current->pid, caller); 679 680 #pragma GCC diagnostic push 681 #ifndef __clang__ 682 #pragma GCC diagnostic ignored "-Wsuggest-attribute=format" 683 #endif 684 if (args) 685 vprintk(args->fmt, args->args); 686 #pragma GCC diagnostic pop 687 688 print_modules(); 689 690 if (regs) 691 show_regs(regs); 692 693 check_panic_on_warn("kernel"); 694 695 if (!regs) 696 dump_stack(); 697 698 print_irqtrace_events(current); 699 700 print_oops_end_marker(); 701 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller); 702 703 /* Just a warning, don't kill lockdep. */ 704 add_taint(taint, LOCKDEP_STILL_OK); 705 } 706 707 #ifdef CONFIG_BUG 708 #ifndef __WARN_FLAGS 709 void warn_slowpath_fmt(const char *file, int line, unsigned taint, 710 const char *fmt, ...) 711 { 712 bool rcu = warn_rcu_enter(); 713 struct warn_args args; 714 715 pr_warn(CUT_HERE); 716 717 if (!fmt) { 718 __warn(file, line, __builtin_return_address(0), taint, 719 NULL, NULL); 720 warn_rcu_exit(rcu); 721 return; 722 } 723 724 args.fmt = fmt; 725 va_start(args.args, fmt); 726 __warn(file, line, __builtin_return_address(0), taint, NULL, &args); 727 va_end(args.args); 728 warn_rcu_exit(rcu); 729 } 730 EXPORT_SYMBOL(warn_slowpath_fmt); 731 #else 732 void __warn_printk(const char *fmt, ...) 733 { 734 bool rcu = warn_rcu_enter(); 735 va_list args; 736 737 pr_warn(CUT_HERE); 738 739 va_start(args, fmt); 740 vprintk(fmt, args); 741 va_end(args); 742 warn_rcu_exit(rcu); 743 } 744 EXPORT_SYMBOL(__warn_printk); 745 #endif 746 747 /* Support resetting WARN*_ONCE state */ 748 749 static int clear_warn_once_set(void *data, u64 val) 750 { 751 generic_bug_clear_once(); 752 memset(__start_once, 0, __end_once - __start_once); 753 return 0; 754 } 755 756 DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, 757 "%lld\n"); 758 759 static __init int register_warn_debugfs(void) 760 { 761 /* Don't care about failure */ 762 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, 763 &clear_warn_once_fops); 764 return 0; 765 } 766 767 device_initcall(register_warn_debugfs); 768 #endif 769 770 #ifdef CONFIG_STACKPROTECTOR 771 772 /* 773 * Called when gcc's -fstack-protector feature is used, and 774 * gcc detects corruption of the on-stack canary value 775 */ 776 __visible noinstr void __stack_chk_fail(void) 777 { 778 instrumentation_begin(); 779 panic("stack-protector: Kernel stack is corrupted in: %pB", 780 __builtin_return_address(0)); 781 instrumentation_end(); 782 } 783 EXPORT_SYMBOL(__stack_chk_fail); 784 785 #endif 786 787 core_param(panic, panic_timeout, int, 0644); 788 core_param(panic_print, panic_print, ulong, 0644); 789 core_param(pause_on_oops, pause_on_oops, int, 0644); 790 core_param(panic_on_warn, panic_on_warn, int, 0644); 791 core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); 792 793 static int __init oops_setup(char *s) 794 { 795 if (!s) 796 return -EINVAL; 797 if (!strcmp(s, "panic")) 798 panic_on_oops = 1; 799 return 0; 800 } 801 early_param("oops", oops_setup); 802 803 static int __init panic_on_taint_setup(char *s) 804 { 805 char *taint_str; 806 807 if (!s) 808 return -EINVAL; 809 810 taint_str = strsep(&s, ","); 811 if (kstrtoul(taint_str, 16, &panic_on_taint)) 812 return -EINVAL; 813 814 /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ 815 panic_on_taint &= TAINT_FLAGS_MAX; 816 817 if (!panic_on_taint) 818 return -EINVAL; 819 820 if (s && !strcmp(s, "nousertaint")) 821 panic_on_taint_nousertaint = true; 822 823 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n", 824 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint)); 825 826 return 0; 827 } 828 early_param("panic_on_taint", panic_on_taint_setup); 829