Merge tag 'hwlock-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc...
[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>
5a5d7e9b 37#include <linux/context_tracking.h>
23b36fec 38#include <trace/events/error_report.h>
b1fca27d 39#include <asm/sections.h>
1da177e4 40
c7ff0d9c
TS
41#define PANIC_TIMER_STEP 100
42#define PANIC_BLINK_SPD 18
43
60c958d8
GP
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 */
9df91869 49static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
50#else
51#define sysctl_oops_all_cpu_backtrace 0
60c958d8
GP
52#endif /* CONFIG_SMP */
53
2a01bb38 54int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
bc4f2f54 55static unsigned long tainted_mask =
595b893e 56 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
dd287796
AM
57static int pause_on_oops;
58static int pause_on_oops_flag;
59static DEFINE_SPINLOCK(pause_on_oops_lock);
5375b708 60bool crash_kexec_post_notifiers;
9e3961a0 61int panic_on_warn __read_mostly;
db38d5c1
RA
62unsigned long panic_on_taint;
63bool panic_on_taint_nousertaint = false;
9fc9e278 64static unsigned int warn_limit __read_mostly;
1da177e4 65
5800dc3c 66int panic_timeout = CONFIG_PANIC_TIMEOUT;
81e88fdc 67EXPORT_SYMBOL_GPL(panic_timeout);
1da177e4 68
d999bd93
FT
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
de6da1e8 74#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020
8d470a45 75#define PANIC_PRINT_ALL_CPU_BT 0x00000040
81c9d43f 76unsigned long panic_print;
d999bd93 77
e041c683 78ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
1da177e4
LT
79
80EXPORT_SYMBOL(panic_notifier_list);
81
9360d035 82#ifdef CONFIG_SYSCTL
9df91869 83static struct ctl_table kern_panic_table[] = {
9360d035 84#ifdef CONFIG_SMP
9df91869 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 },
9360d035 94#endif
9fc9e278
KC
95 {
96 .procname = "warn_limit",
97 .data = &warn_limit,
98 .maxlen = sizeof(warn_limit),
99 .mode = 0644,
100 .proc_handler = proc_douintvec,
101 },
9df91869 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
8b05aa26
KC
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
c7ff0d9c 132static long no_blink(int state)
8aeee85a 133{
c7ff0d9c 134 return 0;
8aeee85a
AB
135}
136
c7ff0d9c
TS
137/* Returns how long it waited in ms */
138long (*panic_blink)(int state);
139EXPORT_SYMBOL(panic_blink);
140
93e13a36
MH
141/*
142 * Stop ourself in panic -- architecture code may override this
143 */
144void __weak panic_smp_self_stop(void)
145{
146 while (1)
147 cpu_relax();
148}
149
58c5661f
HK
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 nmi_panic_self_stop(struct pt_regs *regs)
155{
156 panic_smp_self_stop();
157}
158
0ee59413
HK
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
1717f209
HK
185atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
186
ebc41f20
HK
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
f953f140 207static void panic_print_sys_info(bool console_flush)
d999bd93 208{
f953f140
GP
209 if (console_flush) {
210 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
211 console_flush_on_panic(CONSOLE_REPLAY_ALL);
212 return;
213 }
de6da1e8 214
8d470a45
GP
215 if (panic_print & PANIC_PRINT_ALL_CPU_BT)
216 trigger_all_cpu_backtrace();
217
d999bd93
FT
218 if (panic_print & PANIC_PRINT_TASK_INFO)
219 show_state();
220
221 if (panic_print & PANIC_PRINT_MEM_INFO)
222 show_mem(0, NULL);
223
224 if (panic_print & PANIC_PRINT_TIMER_INFO)
225 sysrq_timer_list_show();
226
227 if (panic_print & PANIC_PRINT_LOCK_INFO)
228 debug_show_all_locks();
229
230 if (panic_print & PANIC_PRINT_FTRACE_INFO)
231 ftrace_dump(DUMP_ALL);
232}
233
79cc1ba7
KC
234void check_panic_on_warn(const char *origin)
235{
7535b832
KC
236 unsigned int limit;
237
79cc1ba7
KC
238 if (panic_on_warn)
239 panic("%s: panic_on_warn set ...\n", origin);
9fc9e278 240
7535b832
KC
241 limit = READ_ONCE(warn_limit);
242 if (atomic_inc_return(&warn_count) >= limit && limit)
9fc9e278 243 panic("%s: system warned too often (kernel.warn_limit is %d)",
7535b832 244 origin, limit);
79cc1ba7
KC
245}
246
1da177e4
LT
247/**
248 * panic - halt the system
249 * @fmt: The text string to print
250 *
251 * Display a message, then perform cleanups.
252 *
253 * This function never returns.
254 */
9402c95f 255void panic(const char *fmt, ...)
1da177e4 256{
1da177e4
LT
257 static char buf[1024];
258 va_list args;
b49dec1c 259 long i, i_next = 0, len;
c7ff0d9c 260 int state = 0;
1717f209 261 int old_cpu, this_cpu;
b26e27dd 262 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
1da177e4 263
1a2383e8
TY
264 if (panic_on_warn) {
265 /*
266 * This thread may hit another WARN() in the panic path.
267 * Resetting this prevents additional WARN() from panicking the
268 * system on this thread. Other threads are blocked by the
269 * panic_mutex in panic().
270 */
271 panic_on_warn = 0;
272 }
273
190320c3
VM
274 /*
275 * Disable local interrupts. This will prevent panic_smp_self_stop
276 * from deadlocking the first cpu that invokes the panic, since
277 * there is nothing to prevent an interrupt handler (that runs
1717f209 278 * after setting panic_cpu) from invoking panic() again.
190320c3
VM
279 */
280 local_irq_disable();
20bb759a 281 preempt_disable_notrace();
190320c3 282
dc009d92 283 /*
c95dbf27
IM
284 * It's possible to come here directly from a panic-assertion and
285 * not have preempt disabled. Some functions called from here want
dc009d92 286 * preempt to be disabled. No point enabling it later though...
93e13a36
MH
287 *
288 * Only one CPU is allowed to execute the panic code from here. For
289 * multiple parallel invocations of panic, all other CPUs either
290 * stop themself or will wait until they are stopped by the 1st CPU
291 * with smp_send_stop().
1717f209
HK
292 *
293 * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
294 * comes here, so go ahead.
295 * `old_cpu == this_cpu' means we came from nmi_panic() which sets
296 * panic_cpu to this CPU. In this case, this is also the 1st CPU.
dc009d92 297 */
1717f209
HK
298 this_cpu = raw_smp_processor_id();
299 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
300
301 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
93e13a36 302 panic_smp_self_stop();
dc009d92 303
5b530fc1 304 console_verbose();
1da177e4
LT
305 bust_spinlocks(1);
306 va_start(args, fmt);
b49dec1c 307 len = vscnprintf(buf, sizeof(buf), fmt, args);
1da177e4 308 va_end(args);
b49dec1c
BP
309
310 if (len && buf[len - 1] == '\n')
311 buf[len - 1] = '\0';
312
d7c0847f 313 pr_emerg("Kernel panic - not syncing: %s\n", buf);
5cb27301 314#ifdef CONFIG_DEBUG_BUGVERBOSE
6e6f0a1f
AK
315 /*
316 * Avoid nested stack-dumping if a panic occurs during oops processing
317 */
026ee1f6 318 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
6e6f0a1f 319 dump_stack();
5cb27301 320#endif
1da177e4 321
7d92bda2
DA
322 /*
323 * If kgdb is enabled, give it a chance to run before we stop all
324 * the other CPUs or else we won't be able to debug processes left
325 * running on them.
326 */
327 kgdb_panic(buf);
328
dc009d92
EB
329 /*
330 * If we have crashed and we have a crash kernel loaded let it handle
331 * everything else.
f06e5153
MH
332 * If we want to run this after calling panic_notifiers, pass
333 * the "crash_kexec_post_notifiers" option to the kernel.
7bbee5ca
HK
334 *
335 * Bypass the panic_cpu check and call __crash_kexec directly.
dc009d92 336 */
b26e27dd 337 if (!_crash_kexec_post_notifiers) {
7bbee5ca 338 __crash_kexec(NULL);
dc009d92 339
0ee59413
HK
340 /*
341 * Note smp_send_stop is the usual smp shutdown function, which
342 * unfortunately means it may not be hardened to work in a
343 * panic situation.
344 */
345 smp_send_stop();
346 } else {
347 /*
348 * If we want to do crash dump after notifier calls and
349 * kmsg_dump, we will need architecture dependent extra
350 * works in addition to stopping other CPUs.
351 */
352 crash_smp_send_stop();
353 }
1da177e4 354
6723734c
KC
355 /*
356 * Run any panic handlers, including those that might need to
357 * add information to the kmsg dump output.
358 */
e041c683 359 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
1da177e4 360
f953f140
GP
361 panic_print_sys_info(false);
362
6723734c
KC
363 kmsg_dump(KMSG_DUMP_PANIC);
364
f06e5153
MH
365 /*
366 * If you doubt kdump always works fine in any situation,
367 * "crash_kexec_post_notifiers" offers you a chance to run
368 * panic_notifiers and dumping kmsg before kdump.
369 * Note: since some panic_notifiers can make crashed kernel
370 * more unstable, it can increase risks of the kdump failure too.
7bbee5ca
HK
371 *
372 * Bypass the panic_cpu check and call __crash_kexec directly.
f06e5153 373 */
b26e27dd 374 if (_crash_kexec_post_notifiers)
7bbee5ca 375 __crash_kexec(NULL);
f06e5153 376
c7c3f05e 377 console_unblank();
d014e889 378
08d78658
VK
379 /*
380 * We may have ended up stopping the CPU holding the lock (in
381 * smp_send_stop()) while still having some valuable data in the console
382 * buffer. Try to acquire the lock then release it regardless of the
7625b3a0
VK
383 * result. The release will also print the buffers out. Locks debug
384 * should be disabled to avoid reporting bad unlock balance when
385 * panic() is not being callled from OOPS.
08d78658 386 */
7625b3a0 387 debug_locks_off();
de6da1e8 388 console_flush_on_panic(CONSOLE_FLUSH_PENDING);
08d78658 389
f953f140 390 panic_print_sys_info(true);
d999bd93 391
c7ff0d9c
TS
392 if (!panic_blink)
393 panic_blink = no_blink;
394
dc009d92 395 if (panic_timeout > 0) {
1da177e4 396 /*
c95dbf27
IM
397 * Delay timeout seconds before rebooting the machine.
398 * We can't use the "normal" timers since we just panicked.
399 */
ff7a28a0 400 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
c95dbf27 401
c7ff0d9c 402 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
1da177e4 403 touch_nmi_watchdog();
c7ff0d9c
TS
404 if (i >= i_next) {
405 i += panic_blink(state ^= 1);
406 i_next = i + 3600 / PANIC_BLINK_SPD;
407 }
408 mdelay(PANIC_TIMER_STEP);
1da177e4 409 }
4302fbc8
HD
410 }
411 if (panic_timeout != 0) {
c95dbf27
IM
412 /*
413 * This will not be a clean reboot, with everything
414 * shutting down. But if there is a chance of
415 * rebooting the system it will be rebooted.
1da177e4 416 */
b287a25a
AK
417 if (panic_reboot_mode != REBOOT_UNDEFINED)
418 reboot_mode = panic_reboot_mode;
2f048ea8 419 emergency_restart();
1da177e4
LT
420 }
421#ifdef __sparc__
422 {
423 extern int stop_a_enabled;
a271c241 424 /* Make sure the user can actually press Stop-A (L1-A) */
1da177e4 425 stop_a_enabled = 1;
7db60d05
VK
426 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
427 "twice on console to return to the boot prom\n");
1da177e4
LT
428 }
429#endif
347a8dc3 430#if defined(CONFIG_S390)
98587c2d 431 disabled_wait();
1da177e4 432#endif
5ad75105 433 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
c39ea0b9
FT
434
435 /* Do not scroll important messages printed above */
436 suppress_printk = 1;
1da177e4 437 local_irq_enable();
c7ff0d9c 438 for (i = 0; ; i += PANIC_TIMER_STEP) {
c22db941 439 touch_softlockup_watchdog();
c7ff0d9c
TS
440 if (i >= i_next) {
441 i += panic_blink(state ^= 1);
442 i_next = i + 3600 / PANIC_BLINK_SPD;
443 }
444 mdelay(PANIC_TIMER_STEP);
1da177e4
LT
445 }
446}
447
448EXPORT_SYMBOL(panic);
449
7fd8329b
PM
450/*
451 * TAINT_FORCED_RMMOD could be a per-module flag but the module
452 * is being removed anyway.
453 */
454const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
47d4b263
KC
455 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
456 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
457 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
458 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
459 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
460 [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
461 [ TAINT_USER ] = { 'U', ' ', false },
462 [ TAINT_DIE ] = { 'D', ' ', false },
463 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
464 [ TAINT_WARN ] = { 'W', ' ', false },
465 [ TAINT_CRAP ] = { 'C', ' ', true },
466 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
467 [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
468 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
469 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
470 [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
471 [ TAINT_AUX ] = { 'X', ' ', true },
bc4f2f54 472 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
2852ca7f 473 [ TAINT_TEST ] = { 'N', ' ', true },
25ddbb18
AK
474};
475
1da177e4 476/**
9c4560e5 477 * print_tainted - return a string to represent the kernel taint state.
1da177e4 478 *
57043247 479 * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst
1da177e4 480 *
9c4560e5
KC
481 * The string is overwritten by the next call to print_tainted(),
482 * but is always NULL terminated.
1da177e4 483 */
1da177e4
LT
484const char *print_tainted(void)
485{
7fd8329b 486 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
25ddbb18 487
47d4b263
KC
488 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
489
25ddbb18
AK
490 if (tainted_mask) {
491 char *s;
492 int i;
493
494 s = buf + sprintf(buf, "Tainted: ");
7fd8329b
PM
495 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
496 const struct taint_flag *t = &taint_flags[i];
497 *s++ = test_bit(i, &tainted_mask) ?
5eb7c0d0 498 t->c_true : t->c_false;
25ddbb18
AK
499 }
500 *s = 0;
501 } else
1da177e4 502 snprintf(buf, sizeof(buf), "Not tainted");
c95dbf27
IM
503
504 return buf;
1da177e4
LT
505}
506
25ddbb18 507int test_taint(unsigned flag)
1da177e4 508{
25ddbb18
AK
509 return test_bit(flag, &tainted_mask);
510}
511EXPORT_SYMBOL(test_taint);
512
513unsigned long get_taint(void)
514{
515 return tainted_mask;
1da177e4 516}
dd287796 517
373d4d09
RR
518/**
519 * add_taint: add a taint flag if not already set.
520 * @flag: one of the TAINT_* constants.
521 * @lockdep_ok: whether lock debugging is still OK.
522 *
523 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
524 * some notewortht-but-not-corrupting cases, it can be set to true.
525 */
526void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
dd287796 527{
373d4d09 528 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
d7c0847f 529 pr_warn("Disabling lock debugging due to kernel taint\n");
9eeba613 530
25ddbb18 531 set_bit(flag, &tainted_mask);
db38d5c1
RA
532
533 if (tainted_mask & panic_on_taint) {
534 panic_on_taint = 0;
535 panic("panic_on_taint set ...");
536 }
dd287796 537}
1da177e4 538EXPORT_SYMBOL(add_taint);
dd287796
AM
539
540static void spin_msec(int msecs)
541{
542 int i;
543
544 for (i = 0; i < msecs; i++) {
545 touch_nmi_watchdog();
546 mdelay(1);
547 }
548}
549
550/*
551 * It just happens that oops_enter() and oops_exit() are identically
552 * implemented...
553 */
554static void do_oops_enter_exit(void)
555{
556 unsigned long flags;
557 static int spin_counter;
558
559 if (!pause_on_oops)
560 return;
561
562 spin_lock_irqsave(&pause_on_oops_lock, flags);
563 if (pause_on_oops_flag == 0) {
564 /* This CPU may now print the oops message */
565 pause_on_oops_flag = 1;
566 } else {
567 /* We need to stall this CPU */
568 if (!spin_counter) {
569 /* This CPU gets to do the counting */
570 spin_counter = pause_on_oops;
571 do {
572 spin_unlock(&pause_on_oops_lock);
573 spin_msec(MSEC_PER_SEC);
574 spin_lock(&pause_on_oops_lock);
575 } while (--spin_counter);
576 pause_on_oops_flag = 0;
577 } else {
578 /* This CPU waits for a different one */
579 while (spin_counter) {
580 spin_unlock(&pause_on_oops_lock);
581 spin_msec(1);
582 spin_lock(&pause_on_oops_lock);
583 }
584 }
585 }
586 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
587}
588
589/*
c95dbf27
IM
590 * Return true if the calling CPU is allowed to print oops-related info.
591 * This is a bit racy..
dd287796 592 */
79076e12 593bool oops_may_print(void)
dd287796
AM
594{
595 return pause_on_oops_flag == 0;
596}
597
598/*
599 * Called when the architecture enters its oops handler, before it prints
c95dbf27
IM
600 * anything. If this is the first CPU to oops, and it's oopsing the first
601 * time then let it proceed.
dd287796 602 *
c95dbf27
IM
603 * This is all enabled by the pause_on_oops kernel boot option. We do all
604 * this to ensure that oopses don't scroll off the screen. It has the
605 * side-effect of preventing later-oopsing CPUs from mucking up the display,
606 * too.
dd287796 607 *
c95dbf27
IM
608 * It turns out that the CPU which is allowed to print ends up pausing for
609 * the right duration, whereas all the other CPUs pause for twice as long:
610 * once in oops_enter(), once in oops_exit().
dd287796
AM
611 */
612void oops_enter(void)
613{
bdff7870 614 tracing_off();
c95dbf27
IM
615 /* can't trust the integrity of the kernel anymore: */
616 debug_locks_off();
dd287796 617 do_oops_enter_exit();
60c958d8
GP
618
619 if (sysctl_oops_all_cpu_backtrace)
620 trigger_all_cpu_backtrace();
dd287796
AM
621}
622
63037f74 623static void print_oops_end_marker(void)
71c33911 624{
e83a4472 625 pr_warn("---[ end trace %016llx ]---\n", 0ULL);
71c33911
AV
626}
627
dd287796
AM
628/*
629 * Called when the architecture exits its oops handler, after printing
630 * everything.
631 */
632void oops_exit(void)
633{
634 do_oops_enter_exit();
71c33911 635 print_oops_end_marker();
456b565c 636 kmsg_dump(KMSG_DUMP_OOPS);
dd287796 637}
3162f751 638
2553b67a 639struct warn_args {
0f6f49a8 640 const char *fmt;
a8f18b90 641 va_list args;
0f6f49a8 642};
bd89bb29 643
2553b67a
JP
644void __warn(const char *file, int line, void *caller, unsigned taint,
645 struct pt_regs *regs, struct warn_args *args)
0f6f49a8 646{
de7edd31
SRRH
647 disable_trace_on_warning();
648
2553b67a
JP
649 if (file)
650 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
651 raw_smp_processor_id(), current->pid, file, line,
652 caller);
653 else
654 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
655 raw_smp_processor_id(), current->pid, caller);
74853dba 656
0f6f49a8
LT
657 if (args)
658 vprintk(args->fmt, args->args);
a8f18b90 659
3f388f28
AK
660 print_modules();
661
662 if (regs)
663 show_regs(regs);
664
79cc1ba7 665 check_panic_on_warn("kernel");
9e3961a0 666
2f31ad64
CL
667 if (!regs)
668 dump_stack();
2553b67a 669
4c281074
SRV
670 print_irqtrace_events(current);
671
a8f18b90 672 print_oops_end_marker();
23b36fec 673 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller);
2553b67a 674
373d4d09
RR
675 /* Just a warning, don't kill lockdep. */
676 add_taint(taint, LOCKDEP_STILL_OK);
a8f18b90 677}
0f6f49a8 678
2da1ead4 679#ifndef __WARN_FLAGS
ee871133
KC
680void warn_slowpath_fmt(const char *file, int line, unsigned taint,
681 const char *fmt, ...)
b2be0527 682{
5a5d7e9b 683 bool rcu = warn_rcu_enter();
2553b67a 684 struct warn_args args;
b2be0527 685
d38aba49
KC
686 pr_warn(CUT_HERE);
687
f2f84b05 688 if (!fmt) {
f2f84b05
KC
689 __warn(file, line, __builtin_return_address(0), taint,
690 NULL, NULL);
691 return;
692 }
693
b2be0527
BH
694 args.fmt = fmt;
695 va_start(args.args, fmt);
2553b67a 696 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
b2be0527 697 va_end(args.args);
5a5d7e9b 698 warn_rcu_exit(rcu);
b2be0527 699}
ee871133 700EXPORT_SYMBOL(warn_slowpath_fmt);
a7bed27a
KC
701#else
702void __warn_printk(const char *fmt, ...)
703{
5a5d7e9b 704 bool rcu = warn_rcu_enter();
a7bed27a
KC
705 va_list args;
706
707 pr_warn(CUT_HERE);
708
709 va_start(args, fmt);
710 vprintk(fmt, args);
711 va_end(args);
5a5d7e9b 712 warn_rcu_exit(rcu);
a7bed27a
KC
713}
714EXPORT_SYMBOL(__warn_printk);
79b4cc5e
AV
715#endif
716
b1fca27d
AK
717#ifdef CONFIG_BUG
718
719/* Support resetting WARN*_ONCE state */
720
721static int clear_warn_once_set(void *data, u64 val)
722{
aaf5dcfb 723 generic_bug_clear_once();
b1fca27d
AK
724 memset(__start_once, 0, __end_once - __start_once);
725 return 0;
726}
727
4169680e
Y
728DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
729 "%lld\n");
b1fca27d
AK
730
731static __init int register_warn_debugfs(void)
732{
733 /* Don't care about failure */
4169680e
Y
734 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
735 &clear_warn_once_fops);
b1fca27d
AK
736 return 0;
737}
738
739device_initcall(register_warn_debugfs);
740#endif
741
050e9baa 742#ifdef CONFIG_STACKPROTECTOR
54371a43 743
3162f751
AV
744/*
745 * Called when gcc's -fstack-protector feature is used, and
746 * gcc detects corruption of the on-stack canary value
747 */
5916d5f9 748__visible noinstr void __stack_chk_fail(void)
3162f751 749{
5916d5f9 750 instrumentation_begin();
95c4fb78 751 panic("stack-protector: Kernel stack is corrupted in: %pB",
517a92c4 752 __builtin_return_address(0));
5916d5f9 753 instrumentation_end();
3162f751
AV
754}
755EXPORT_SYMBOL(__stack_chk_fail);
54371a43 756
3162f751 757#endif
f44dd164
RR
758
759core_param(panic, panic_timeout, int, 0644);
d999bd93 760core_param(panic_print, panic_print, ulong, 0644);
f44dd164 761core_param(pause_on_oops, pause_on_oops, int, 0644);
9e3961a0 762core_param(panic_on_warn, panic_on_warn, int, 0644);
b26e27dd 763core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
f06e5153 764
d404ab0a
OH
765static int __init oops_setup(char *s)
766{
767 if (!s)
768 return -EINVAL;
769 if (!strcmp(s, "panic"))
770 panic_on_oops = 1;
771 return 0;
772}
773early_param("oops", oops_setup);
db38d5c1
RA
774
775static int __init panic_on_taint_setup(char *s)
776{
777 char *taint_str;
778
779 if (!s)
780 return -EINVAL;
781
782 taint_str = strsep(&s, ",");
783 if (kstrtoul(taint_str, 16, &panic_on_taint))
784 return -EINVAL;
785
786 /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */
787 panic_on_taint &= TAINT_FLAGS_MAX;
788
789 if (!panic_on_taint)
790 return -EINVAL;
791
792 if (s && !strcmp(s, "nousertaint"))
793 panic_on_taint_nousertaint = true;
794
5d5dd3e4
AS
795 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n",
796 panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint));
db38d5c1
RA
797
798 return 0;
799}
800early_param("panic_on_taint", panic_on_taint_setup);