cpuidle: drivers: firmware: psci: Dont instrument suspend code
[linux-block.git] / kernel / panic.c
CommitLineData
457c8996 1// SPDX-License-Identifier: GPL-2.0-only
1da177e4
LT
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 */
c95dbf27 12#include <linux/debug_locks.h>
b17b0153 13#include <linux/sched/debug.h>
c95dbf27 14#include <linux/interrupt.h>
7d92bda2 15#include <linux/kgdb.h>
456b565c 16#include <linux/kmsg_dump.h>
c95dbf27
IM
17#include <linux/kallsyms.h>
18#include <linux/notifier.h>
c7c3f05e 19#include <linux/vt_kern.h>
1da177e4 20#include <linux/module.h>
c95dbf27 21#include <linux/random.h>
de7edd31 22#include <linux/ftrace.h>
1da177e4 23#include <linux/reboot.h>
c95dbf27
IM
24#include <linux/delay.h>
25#include <linux/kexec.h>
f39650de 26#include <linux/panic_notifier.h>
c95dbf27 27#include <linux/sched.h>
5d5dd3e4 28#include <linux/string_helpers.h>
1da177e4 29#include <linux/sysrq.h>
c95dbf27 30#include <linux/init.h>
1da177e4 31#include <linux/nmi.h>
08d78658 32#include <linux/console.h>
2553b67a 33#include <linux/bug.h>
7a46ec0e 34#include <linux/ratelimit.h>
b1fca27d 35#include <linux/debugfs.h>
8b05aa26 36#include <linux/sysfs.h>
23b36fec 37#include <trace/events/error_report.h>
b1fca27d 38#include <asm/sections.h>
1da177e4 39
c7ff0d9c
TS
40#define PANIC_TIMER_STEP 100
41#define PANIC_BLINK_SPD 18
42
60c958d8
GP
43#ifdef CONFIG_SMP
44/*
45 * Should we dump all CPUs backtraces in an oops event?
46 * Defaults to 0, can be changed via sysctl.
47 */
9df91869 48static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
49#else
50#define sysctl_oops_all_cpu_backtrace 0
60c958d8
GP
51#endif /* CONFIG_SMP */
52
2a01bb38 53int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
bc4f2f54 54static unsigned long tainted_mask =
595b893e 55 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
dd287796
AM
56static int pause_on_oops;
57static int pause_on_oops_flag;
58static DEFINE_SPINLOCK(pause_on_oops_lock);
5375b708 59bool crash_kexec_post_notifiers;
9e3961a0 60int panic_on_warn __read_mostly;
db38d5c1
RA
61unsigned long panic_on_taint;
62bool panic_on_taint_nousertaint = false;
9fc9e278 63static unsigned int warn_limit __read_mostly;
1da177e4 64
5800dc3c 65int panic_timeout = CONFIG_PANIC_TIMEOUT;
81e88fdc 66EXPORT_SYMBOL_GPL(panic_timeout);
1da177e4 67
d999bd93
FT
68#define PANIC_PRINT_TASK_INFO 0x00000001
69#define PANIC_PRINT_MEM_INFO 0x00000002
70#define PANIC_PRINT_TIMER_INFO 0x00000004
71#define PANIC_PRINT_LOCK_INFO 0x00000008
72#define PANIC_PRINT_FTRACE_INFO 0x00000010
de6da1e8 73#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020
8d470a45 74#define PANIC_PRINT_ALL_CPU_BT 0x00000040
81c9d43f 75unsigned long panic_print;
d999bd93 76
e041c683 77ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
1da177e4
LT
78
79EXPORT_SYMBOL(panic_notifier_list);
80
9360d035 81#ifdef CONFIG_SYSCTL
9df91869 82static struct ctl_table kern_panic_table[] = {
9360d035 83#ifdef CONFIG_SMP
9df91869 84 {
85 .procname = "oops_all_cpu_backtrace",
86 .data = &sysctl_oops_all_cpu_backtrace,
87 .maxlen = sizeof(int),
88 .mode = 0644,
89 .proc_handler = proc_dointvec_minmax,
90 .extra1 = SYSCTL_ZERO,
91 .extra2 = SYSCTL_ONE,
92 },
9360d035 93#endif
9fc9e278
KC
94 {
95 .procname = "warn_limit",
96 .data = &warn_limit,
97 .maxlen = sizeof(warn_limit),
98 .mode = 0644,
99 .proc_handler = proc_douintvec,
100 },
9df91869 101 { }
102};
103
104static __init int kernel_panic_sysctls_init(void)
105{
106 register_sysctl_init("kernel", kern_panic_table);
107 return 0;
108}
109late_initcall(kernel_panic_sysctls_init);
110#endif
111
8b05aa26
KC
112static atomic_t warn_count = ATOMIC_INIT(0);
113
114#ifdef CONFIG_SYSFS
115static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr,
116 char *page)
117{
118 return sysfs_emit(page, "%d\n", atomic_read(&warn_count));
119}
120
121static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count);
122
123static __init int kernel_panic_sysfs_init(void)
124{
125 sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL);
126 return 0;
127}
128late_initcall(kernel_panic_sysfs_init);
129#endif
130
c7ff0d9c 131static long no_blink(int state)
8aeee85a 132{
c7ff0d9c 133 return 0;
8aeee85a
AB
134}
135
c7ff0d9c
TS
136/* Returns how long it waited in ms */
137long (*panic_blink)(int state);
138EXPORT_SYMBOL(panic_blink);
139
93e13a36
MH
140/*
141 * Stop ourself in panic -- architecture code may override this
142 */
143void __weak panic_smp_self_stop(void)
144{
145 while (1)
146 cpu_relax();
147}
148
58c5661f
HK
149/*
150 * Stop ourselves in NMI context if another CPU has already panicked. Arch code
151 * may override this to prepare for crash dumping, e.g. save regs info.
152 */
153void __weak nmi_panic_self_stop(struct pt_regs *regs)
154{
155 panic_smp_self_stop();
156}
157
0ee59413
HK
158/*
159 * Stop other CPUs in panic. Architecture dependent code may override this
160 * with more suitable version. For example, if the architecture supports
161 * crash dump, it should save registers of each stopped CPU and disable
162 * per-CPU features such as virtualization extensions.
163 */
164void __weak crash_smp_send_stop(void)
165{
166 static int cpus_stopped;
167
168 /*
169 * This function can be called twice in panic path, but obviously
170 * we execute this only once.
171 */
172 if (cpus_stopped)
173 return;
174
175 /*
176 * Note smp_send_stop is the usual smp shutdown function, which
177 * unfortunately means it may not be hardened to work in a panic
178 * situation.
179 */
180 smp_send_stop();
181 cpus_stopped = 1;
182}
183
1717f209
HK
184atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
185
ebc41f20
HK
186/*
187 * A variant of panic() called from NMI context. We return if we've already
188 * panicked on this CPU. If another CPU already panicked, loop in
189 * nmi_panic_self_stop() which can provide architecture dependent code such
190 * as saving register state for crash dump.
191 */
192void nmi_panic(struct pt_regs *regs, const char *msg)
193{
194 int old_cpu, cpu;
195
196 cpu = raw_smp_processor_id();
197 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
198
199 if (old_cpu == PANIC_CPU_INVALID)
200 panic("%s", msg);
201 else if (old_cpu != cpu)
202 nmi_panic_self_stop(regs);
203}
204EXPORT_SYMBOL(nmi_panic);
205
f953f140 206static void panic_print_sys_info(bool console_flush)
d999bd93 207{
f953f140
GP
208 if (console_flush) {
209 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
210 console_flush_on_panic(CONSOLE_REPLAY_ALL);
211 return;
212 }
de6da1e8 213
8d470a45
GP
214 if (panic_print & PANIC_PRINT_ALL_CPU_BT)
215 trigger_all_cpu_backtrace();
216
d999bd93
FT
217 if (panic_print & PANIC_PRINT_TASK_INFO)
218 show_state();
219
220 if (panic_print & PANIC_PRINT_MEM_INFO)
221 show_mem(0, NULL);
222
223 if (panic_print & PANIC_PRINT_TIMER_INFO)
224 sysrq_timer_list_show();
225
226 if (panic_print & PANIC_PRINT_LOCK_INFO)
227 debug_show_all_locks();
228
229 if (panic_print & PANIC_PRINT_FTRACE_INFO)
230 ftrace_dump(DUMP_ALL);
231}
232
79cc1ba7
KC
233void check_panic_on_warn(const char *origin)
234{
7535b832
KC
235 unsigned int limit;
236
79cc1ba7
KC
237 if (panic_on_warn)
238 panic("%s: panic_on_warn set ...\n", origin);
9fc9e278 239
7535b832
KC
240 limit = READ_ONCE(warn_limit);
241 if (atomic_inc_return(&warn_count) >= limit && limit)
9fc9e278 242 panic("%s: system warned too often (kernel.warn_limit is %d)",
7535b832 243 origin, limit);
79cc1ba7
KC
244}
245
1da177e4
LT
246/**
247 * panic - halt the system
248 * @fmt: The text string to print
249 *
250 * Display a message, then perform cleanups.
251 *
252 * This function never returns.
253 */
9402c95f 254void panic(const char *fmt, ...)
1da177e4 255{
1da177e4
LT
256 static char buf[1024];
257 va_list args;
b49dec1c 258 long i, i_next = 0, len;
c7ff0d9c 259 int state = 0;
1717f209 260 int old_cpu, this_cpu;
b26e27dd 261 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
1da177e4 262
1a2383e8
TY
263 if (panic_on_warn) {
264 /*
265 * This thread may hit another WARN() in the panic path.
266 * Resetting this prevents additional WARN() from panicking the
267 * system on this thread. Other threads are blocked by the
268 * panic_mutex in panic().
269 */
270 panic_on_warn = 0;
271 }
272
190320c3
VM
273 /*
274 * Disable local interrupts. This will prevent panic_smp_self_stop
275 * from deadlocking the first cpu that invokes the panic, since
276 * there is nothing to prevent an interrupt handler (that runs
1717f209 277 * after setting panic_cpu) from invoking panic() again.
190320c3
VM
278 */
279 local_irq_disable();
20bb759a 280 preempt_disable_notrace();
190320c3 281
dc009d92 282 /*
c95dbf27
IM
283 * It's possible to come here directly from a panic-assertion and
284 * not have preempt disabled. Some functions called from here want
dc009d92 285 * preempt to be disabled. No point enabling it later though...
93e13a36
MH
286 *
287 * Only one CPU is allowed to execute the panic code from here. For
288 * multiple parallel invocations of panic, all other CPUs either
289 * stop themself or will wait until they are stopped by the 1st CPU
290 * with smp_send_stop().
1717f209
HK
291 *
292 * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
293 * comes here, so go ahead.
294 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
295 * panic_cpu to this CPU. In this case, this is also the 1st CPU.
dc009d92 296 */
1717f209
HK
297 this_cpu = raw_smp_processor_id();
298 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
299
300 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
93e13a36 301 panic_smp_self_stop();
dc009d92 302
5b530fc1 303 console_verbose();
1da177e4
LT
304 bust_spinlocks(1);
305 va_start(args, fmt);
b49dec1c 306 len = vscnprintf(buf, sizeof(buf), fmt, args);
1da177e4 307 va_end(args);
b49dec1c
BP
308
309 if (len && buf[len - 1] == '\n')
310 buf[len - 1] = '\0';
311
d7c0847f 312 pr_emerg("Kernel panic - not syncing: %s\n", buf);
5cb27301 313#ifdef CONFIG_DEBUG_BUGVERBOSE
6e6f0a1f
AK
314 /*
315 * Avoid nested stack-dumping if a panic occurs during oops processing
316 */
026ee1f6 317 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
6e6f0a1f 318 dump_stack();
5cb27301 319#endif
1da177e4 320
7d92bda2
DA
321 /*
322 * If kgdb is enabled, give it a chance to run before we stop all
323 * the other CPUs or else we won't be able to debug processes left
324 * running on them.
325 */
326 kgdb_panic(buf);
327
dc009d92
EB
328 /*
329 * If we have crashed and we have a crash kernel loaded let it handle
330 * everything else.
f06e5153
MH
331 * If we want to run this after calling panic_notifiers, pass
332 * the "crash_kexec_post_notifiers" option to the kernel.
7bbee5ca
HK
333 *
334 * Bypass the panic_cpu check and call __crash_kexec directly.
dc009d92 335 */
b26e27dd 336 if (!_crash_kexec_post_notifiers) {
7bbee5ca 337 __crash_kexec(NULL);
dc009d92 338
0ee59413
HK
339 /*
340 * Note smp_send_stop is the usual smp shutdown function, which
341 * unfortunately means it may not be hardened to work in a
342 * panic situation.
343 */
344 smp_send_stop();
345 } else {
346 /*
347 * If we want to do crash dump after notifier calls and
348 * kmsg_dump, we will need architecture dependent extra
349 * works in addition to stopping other CPUs.
350 */
351 crash_smp_send_stop();
352 }
1da177e4 353
6723734c
KC
354 /*
355 * Run any panic handlers, including those that might need to
356 * add information to the kmsg dump output.
357 */
e041c683 358 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
1da177e4 359
f953f140
GP
360 panic_print_sys_info(false);
361
6723734c
KC
362 kmsg_dump(KMSG_DUMP_PANIC);
363
f06e5153
MH
364 /*
365 * If you doubt kdump always works fine in any situation,
366 * "crash_kexec_post_notifiers" offers you a chance to run
367 * panic_notifiers and dumping kmsg before kdump.
368 * Note: since some panic_notifiers can make crashed kernel
369 * more unstable, it can increase risks of the kdump failure too.
7bbee5ca
HK
370 *
371 * Bypass the panic_cpu check and call __crash_kexec directly.
f06e5153 372 */
b26e27dd 373 if (_crash_kexec_post_notifiers)
7bbee5ca 374 __crash_kexec(NULL);
f06e5153 375
c7c3f05e 376 console_unblank();
d014e889 377
08d78658
VK
378 /*
379 * We may have ended up stopping the CPU holding the lock (in
380 * smp_send_stop()) while still having some valuable data in the console
381 * buffer. Try to acquire the lock then release it regardless of the
7625b3a0
VK
382 * result. The release will also print the buffers out. Locks debug
383 * should be disabled to avoid reporting bad unlock balance when
384 * panic() is not being callled from OOPS.
08d78658 385 */
7625b3a0 386 debug_locks_off();
de6da1e8 387 console_flush_on_panic(CONSOLE_FLUSH_PENDING);
08d78658 388
f953f140 389 panic_print_sys_info(true);
d999bd93 390
c7ff0d9c
TS
391 if (!panic_blink)
392 panic_blink = no_blink;
393
dc009d92 394 if (panic_timeout > 0) {
1da177e4 395 /*
c95dbf27
IM
396 * Delay timeout seconds before rebooting the machine.
397 * We can't use the "normal" timers since we just panicked.
398 */
ff7a28a0 399 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
c95dbf27 400
c7ff0d9c 401 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
1da177e4 402 touch_nmi_watchdog();
c7ff0d9c
TS
403 if (i >= i_next) {
404 i += panic_blink(state ^= 1);
405 i_next = i + 3600 / PANIC_BLINK_SPD;
406 }
407 mdelay(PANIC_TIMER_STEP);
1da177e4 408 }
4302fbc8
HD
409 }
410 if (panic_timeout != 0) {
c95dbf27
IM
411 /*
412 * This will not be a clean reboot, with everything
413 * shutting down. But if there is a chance of
414 * rebooting the system it will be rebooted.
1da177e4 415 */
b287a25a
AK
416 if (panic_reboot_mode != REBOOT_UNDEFINED)
417 reboot_mode = panic_reboot_mode;
2f048ea8 418 emergency_restart();
1da177e4
LT
419 }
420#ifdef __sparc__
421 {
422 extern int stop_a_enabled;
a271c241 423 /* Make sure the user can actually press Stop-A (L1-A) */
1da177e4 424 stop_a_enabled = 1;
7db60d05
VK
425 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
426 "twice on console to return to the boot prom\n");
1da177e4
LT
427 }
428#endif
347a8dc3 429#if defined(CONFIG_S390)
98587c2d 430 disabled_wait();
1da177e4 431#endif
5ad75105 432 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
c39ea0b9
FT
433
434 /* Do not scroll important messages printed above */
435 suppress_printk = 1;
1da177e4 436 local_irq_enable();
c7ff0d9c 437 for (i = 0; ; i += PANIC_TIMER_STEP) {
c22db941 438 touch_softlockup_watchdog();
c7ff0d9c
TS
439 if (i >= i_next) {
440 i += panic_blink(state ^= 1);
441 i_next = i + 3600 / PANIC_BLINK_SPD;
442 }
443 mdelay(PANIC_TIMER_STEP);
1da177e4
LT
444 }
445}
446
447EXPORT_SYMBOL(panic);
448
7fd8329b
PM
449/*
450 * TAINT_FORCED_RMMOD could be a per-module flag but the module
451 * is being removed anyway.
452 */
453const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
47d4b263
KC
454 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
455 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
456 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
457 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
458 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
459 [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
460 [ TAINT_USER ] = { 'U', ' ', false },
461 [ TAINT_DIE ] = { 'D', ' ', false },
462 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
463 [ TAINT_WARN ] = { 'W', ' ', false },
464 [ TAINT_CRAP ] = { 'C', ' ', true },
465 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
466 [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
467 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
468 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
469 [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
470 [ TAINT_AUX ] = { 'X', ' ', true },
bc4f2f54 471 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
2852ca7f 472 [ TAINT_TEST ] = { 'N', ' ', true },
25ddbb18
AK
473};
474
1da177e4 475/**
9c4560e5 476 * print_tainted - return a string to represent the kernel taint state.
1da177e4 477 *
57043247 478 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst
1da177e4 479 *
9c4560e5
KC
480 * The string is overwritten by the next call to print_tainted(),
481 * but is always NULL terminated.
1da177e4 482 */
1da177e4
LT
483const char *print_tainted(void)
484{
7fd8329b 485 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
25ddbb18 486
47d4b263
KC
487 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
488
25ddbb18
AK
489 if (tainted_mask) {
490 char *s;
491 int i;
492
493 s = buf + sprintf(buf, "Tainted: ");
7fd8329b
PM
494 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
495 const struct taint_flag *t = &taint_flags[i];
496 *s++ = test_bit(i, &tainted_mask) ?
5eb7c0d0 497 t->c_true : t->c_false;
25ddbb18
AK
498 }
499 *s = 0;
500 } else
1da177e4 501 snprintf(buf, sizeof(buf), "Not tainted");
c95dbf27
IM
502
503 return buf;
1da177e4
LT
504}
505
25ddbb18 506int test_taint(unsigned flag)
1da177e4 507{
25ddbb18
AK
508 return test_bit(flag, &tainted_mask);
509}
510EXPORT_SYMBOL(test_taint);
511
512unsigned long get_taint(void)
513{
514 return tainted_mask;
1da177e4 515}
dd287796 516
373d4d09
RR
517/**
518 * add_taint: add a taint flag if not already set.
519 * @flag: one of the TAINT_* constants.
520 * @lockdep_ok: whether lock debugging is still OK.
521 *
522 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
523 * some notewortht-but-not-corrupting cases, it can be set to true.
524 */
525void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
dd287796 526{
373d4d09 527 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
d7c0847f 528 pr_warn("Disabling lock debugging due to kernel taint\n");
9eeba613 529
25ddbb18 530 set_bit(flag, &tainted_mask);
db38d5c1
RA
531
532 if (tainted_mask & panic_on_taint) {
533 panic_on_taint = 0;
534 panic("panic_on_taint set ...");
535 }
dd287796 536}
1da177e4 537EXPORT_SYMBOL(add_taint);
dd287796
AM
538
539static void spin_msec(int msecs)
540{
541 int i;
542
543 for (i = 0; i < msecs; i++) {
544 touch_nmi_watchdog();
545 mdelay(1);
546 }
547}
548
549/*
550 * It just happens that oops_enter() and oops_exit() are identically
551 * implemented...
552 */
553static void do_oops_enter_exit(void)
554{
555 unsigned long flags;
556 static int spin_counter;
557
558 if (!pause_on_oops)
559 return;
560
561 spin_lock_irqsave(&pause_on_oops_lock, flags);
562 if (pause_on_oops_flag == 0) {
563 /* This CPU may now print the oops message */
564 pause_on_oops_flag = 1;
565 } else {
566 /* We need to stall this CPU */
567 if (!spin_counter) {
568 /* This CPU gets to do the counting */
569 spin_counter = pause_on_oops;
570 do {
571 spin_unlock(&pause_on_oops_lock);
572 spin_msec(MSEC_PER_SEC);
573 spin_lock(&pause_on_oops_lock);
574 } while (--spin_counter);
575 pause_on_oops_flag = 0;
576 } else {
577 /* This CPU waits for a different one */
578 while (spin_counter) {
579 spin_unlock(&pause_on_oops_lock);
580 spin_msec(1);
581 spin_lock(&pause_on_oops_lock);
582 }
583 }
584 }
585 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
586}
587
588/*
c95dbf27
IM
589 * Return true if the calling CPU is allowed to print oops-related info.
590 * This is a bit racy..
dd287796 591 */
79076e12 592bool oops_may_print(void)
dd287796
AM
593{
594 return pause_on_oops_flag == 0;
595}
596
597/*
598 * Called when the architecture enters its oops handler, before it prints
c95dbf27
IM
599 * anything. If this is the first CPU to oops, and it's oopsing the first
600 * time then let it proceed.
dd287796 601 *
c95dbf27
IM
602 * This is all enabled by the pause_on_oops kernel boot option. We do all
603 * this to ensure that oopses don't scroll off the screen. It has the
604 * side-effect of preventing later-oopsing CPUs from mucking up the display,
605 * too.
dd287796 606 *
c95dbf27
IM
607 * It turns out that the CPU which is allowed to print ends up pausing for
608 * the right duration, whereas all the other CPUs pause for twice as long:
609 * once in oops_enter(), once in oops_exit().
dd287796
AM
610 */
611void oops_enter(void)
612{
bdff7870 613 tracing_off();
c95dbf27
IM
614 /* can't trust the integrity of the kernel anymore: */
615 debug_locks_off();
dd287796 616 do_oops_enter_exit();
60c958d8
GP
617
618 if (sysctl_oops_all_cpu_backtrace)
619 trigger_all_cpu_backtrace();
dd287796
AM
620}
621
63037f74 622static void print_oops_end_marker(void)
71c33911 623{
e83a4472 624 pr_warn("---[ end trace %016llx ]---\n", 0ULL);
71c33911
AV
625}
626
dd287796
AM
627/*
628 * Called when the architecture exits its oops handler, after printing
629 * everything.
630 */
631void oops_exit(void)
632{
633 do_oops_enter_exit();
71c33911 634 print_oops_end_marker();
456b565c 635 kmsg_dump(KMSG_DUMP_OOPS);
dd287796 636}
3162f751 637
2553b67a 638struct warn_args {
0f6f49a8 639 const char *fmt;
a8f18b90 640 va_list args;
0f6f49a8 641};
bd89bb29 642
2553b67a
JP
643void __warn(const char *file, int line, void *caller, unsigned taint,
644 struct pt_regs *regs, struct warn_args *args)
0f6f49a8 645{
de7edd31
SRRH
646 disable_trace_on_warning();
647
2553b67a
JP
648 if (file)
649 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
650 raw_smp_processor_id(), current->pid, file, line,
651 caller);
652 else
653 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
654 raw_smp_processor_id(), current->pid, caller);
74853dba 655
0f6f49a8
LT
656 if (args)
657 vprintk(args->fmt, args->args);
a8f18b90 658
3f388f28
AK
659 print_modules();
660
661 if (regs)
662 show_regs(regs);
663
79cc1ba7 664 check_panic_on_warn("kernel");
9e3961a0 665
2f31ad64
CL
666 if (!regs)
667 dump_stack();
2553b67a 668
4c281074
SRV
669 print_irqtrace_events(current);
670
a8f18b90 671 print_oops_end_marker();
23b36fec 672 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller);
2553b67a 673
373d4d09
RR
674 /* Just a warning, don't kill lockdep. */
675 add_taint(taint, LOCKDEP_STILL_OK);
a8f18b90 676}
0f6f49a8 677
2da1ead4 678#ifndef __WARN_FLAGS
ee871133
KC
679void warn_slowpath_fmt(const char *file, int line, unsigned taint,
680 const char *fmt, ...)
b2be0527 681{
2553b67a 682 struct warn_args args;
b2be0527 683
d38aba49
KC
684 pr_warn(CUT_HERE);
685
f2f84b05 686 if (!fmt) {
f2f84b05
KC
687 __warn(file, line, __builtin_return_address(0), taint,
688 NULL, NULL);
689 return;
690 }
691
b2be0527
BH
692 args.fmt = fmt;
693 va_start(args.args, fmt);
2553b67a 694 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
b2be0527
BH
695 va_end(args.args);
696}
ee871133 697EXPORT_SYMBOL(warn_slowpath_fmt);
a7bed27a
KC
698#else
699void __warn_printk(const char *fmt, ...)
700{
701 va_list args;
702
703 pr_warn(CUT_HERE);
704
705 va_start(args, fmt);
706 vprintk(fmt, args);
707 va_end(args);
708}
709EXPORT_SYMBOL(__warn_printk);
79b4cc5e
AV
710#endif
711
b1fca27d
AK
712#ifdef CONFIG_BUG
713
714/* Support resetting WARN*_ONCE state */
715
716static int clear_warn_once_set(void *data, u64 val)
717{
aaf5dcfb 718 generic_bug_clear_once();
b1fca27d
AK
719 memset(__start_once, 0, __end_once - __start_once);
720 return 0;
721}
722
4169680e
Y
723DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
724 "%lld\n");
b1fca27d
AK
725
726static __init int register_warn_debugfs(void)
727{
728 /* Don't care about failure */
4169680e
Y
729 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
730 &clear_warn_once_fops);
b1fca27d
AK
731 return 0;
732}
733
734device_initcall(register_warn_debugfs);
735#endif
736
050e9baa 737#ifdef CONFIG_STACKPROTECTOR
54371a43 738
3162f751
AV
739/*
740 * Called when gcc's -fstack-protector feature is used, and
741 * gcc detects corruption of the on-stack canary value
742 */
5916d5f9 743__visible noinstr void __stack_chk_fail(void)
3162f751 744{
5916d5f9 745 instrumentation_begin();
95c4fb78 746 panic("stack-protector: Kernel stack is corrupted in: %pB",
517a92c4 747 __builtin_return_address(0));
5916d5f9 748 instrumentation_end();
3162f751
AV
749}
750EXPORT_SYMBOL(__stack_chk_fail);
54371a43 751
3162f751 752#endif
f44dd164
RR
753
754core_param(panic, panic_timeout, int, 0644);
d999bd93 755core_param(panic_print, panic_print, ulong, 0644);
f44dd164 756core_param(pause_on_oops, pause_on_oops, int, 0644);
9e3961a0 757core_param(panic_on_warn, panic_on_warn, int, 0644);
b26e27dd 758core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
f06e5153 759
d404ab0a
OH
760static int __init oops_setup(char *s)
761{
762 if (!s)
763 return -EINVAL;
764 if (!strcmp(s, "panic"))
765 panic_on_oops = 1;
766 return 0;
767}
768early_param("oops", oops_setup);
db38d5c1
RA
769
770static int __init panic_on_taint_setup(char *s)
771{
772 char *taint_str;
773
774 if (!s)
775 return -EINVAL;
776
777 taint_str = strsep(&s, ",");
778 if (kstrtoul(taint_str, 16, &panic_on_taint))
779 return -EINVAL;
780
781 /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */
782 panic_on_taint &= TAINT_FLAGS_MAX;
783
784 if (!panic_on_taint)
785 return -EINVAL;
786
787 if (s && !strcmp(s, "nousertaint"))
788 panic_on_taint_nousertaint = true;
789
5d5dd3e4
AS
790 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n",
791 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint));
db38d5c1
RA
792
793 return 0;
794}
795early_param("panic_on_taint", panic_on_taint_setup);