projects/linux·blob v6.10-rc5 · refs

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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 */
49static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
50#else
51#define sysctl_oops_all_cpu_backtrace 0
52#endif /* CONFIG_SMP */
53
54int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
55static unsigned long tainted_mask =
56 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
57static int pause_on_oops;
58static int pause_on_oops_flag;
59static DEFINE_SPINLOCK(pause_on_oops_lock);
60bool crash_kexec_post_notifiers;
61int panic_on_warn __read_mostly;
62unsigned long panic_on_taint;
63bool panic_on_taint_nousertaint = false;
64static unsigned int warn_limit __read_mostly;
65
66int panic_timeout = CONFIG_PANIC_TIMEOUT;
67EXPORT_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
77unsigned long panic_print;
78
79ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
80
81EXPORT_SYMBOL(panic_notifier_list);
82
83#ifdef CONFIG_SYSCTL
84static 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
105static __init int kernel_panic_sysctls_init(void)
106{
107 register_sysctl_init("kernel", kern_panic_table);
108 return 0;
109}
110late_initcall(kernel_panic_sysctls_init);
111#endif
112
113static atomic_t warn_count = ATOMIC_INIT(0);
114
115#ifdef CONFIG_SYSFS
116static 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
122static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count);
123
124static __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}
129late_initcall(kernel_panic_sysfs_init);
130#endif
131
132static long no_blink(int state)
133{
134 return 0;
135}
136
137/* Returns how long it waited in ms */
138long (*panic_blink)(int state);
139EXPORT_SYMBOL(panic_blink);
140
141/*
142 * Stop ourself in panic -- architecture code may override this
143 */
144void __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 */
154void __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 */
165void __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
185atomic_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 */
193void 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}
206EXPORT_SYMBOL(nmi_panic);
207
208static 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
235void 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 */
253static 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 */
280void 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
471EXPORT_SYMBOL(panic);
472
473/*
474 * TAINT_FORCED_RMMOD could be a per-module flag but the module
475 * is being removed anyway.
476 */
477const 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 */
507const 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
530int test_taint(unsigned flag)
531{
532 return test_bit(flag, &tainted_mask);
533}
534EXPORT_SYMBOL(test_taint);
535
536unsigned 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 */
549void 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}
561EXPORT_SYMBOL(add_taint);
562
563static 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 */
577static 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 */
616bool 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 */
635void 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
646static 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 */
655void oops_exit(void)
656{
657 do_oops_enter_exit();
658 print_oops_end_marker();
659 kmsg_dump(KMSG_DUMP_OOPS);
660}
661
662struct warn_args {
663 const char *fmt;
664 va_list args;
665};
666
667void __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
709void 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}
730EXPORT_SYMBOL(warn_slowpath_fmt);
731#else
732void __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}
744EXPORT_SYMBOL(__warn_printk);
745#endif
746
747/* Support resetting WARN*_ONCE state */
748
749static 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
756DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
757 "%lld\n");
758
759static __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
767device_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}
783EXPORT_SYMBOL(__stack_chk_fail);
784
785#endif
786
787core_param(panic, panic_timeout, int, 0644);
788core_param(panic_print, panic_print, ulong, 0644);
789core_param(pause_on_oops, pause_on_oops, int, 0644);
790core_param(panic_on_warn, panic_on_warn, int, 0644);
791core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
792
793static 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}
801early_param("oops", oops_setup);
802
803static 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}
828early_param("panic_on_taint", panic_on_taint_setup);