projects/linux·blob v6.4-rc2 · refs

808 lines · 20.4 KiB

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