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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/sysrq.h>
29#include <linux/init.h>
30#include <linux/nmi.h>
31#include <linux/console.h>
32#include <linux/bug.h>
33#include <linux/ratelimit.h>
34#include <linux/debugfs.h>
35#include <trace/events/error_report.h>
36#include <asm/sections.h>
37
38#define PANIC_TIMER_STEP 100
39#define PANIC_BLINK_SPD 18
40
41#ifdef CONFIG_SMP
42
43
44
45
46static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
47#else
48#define sysctl_oops_all_cpu_backtrace 0
49#endif
50
51int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
52static unsigned long tainted_mask =
53 IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
54static int pause_on_oops;
55static int pause_on_oops_flag;
56static DEFINE_SPINLOCK(pause_on_oops_lock);
57bool crash_kexec_post_notifiers;
58int panic_on_warn __read_mostly;
59unsigned long panic_on_taint;
60bool panic_on_taint_nousertaint = false;
61
62int panic_timeout = CONFIG_PANIC_TIMEOUT;
63EXPORT_SYMBOL_GPL(panic_timeout);
64
65#define PANIC_PRINT_TASK_INFO 0x00000001
66#define PANIC_PRINT_MEM_INFO 0x00000002
67#define PANIC_PRINT_TIMER_INFO 0x00000004
68#define PANIC_PRINT_LOCK_INFO 0x00000008
69#define PANIC_PRINT_FTRACE_INFO 0x00000010
70#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020
71#define PANIC_PRINT_ALL_CPU_BT 0x00000040
72unsigned long panic_print;
73
74ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
75
76EXPORT_SYMBOL(panic_notifier_list);
77
78#if defined(CONFIG_SMP) && defined(CONFIG_SYSCTL)
79static struct ctl_table kern_panic_table[] = {
80 {
81 .procname = "oops_all_cpu_backtrace",
82 .data = &sysctl_oops_all_cpu_backtrace,
83 .maxlen = sizeof(int),
84 .mode = 0644,
85 .proc_handler = proc_dointvec_minmax,
86 .extra1 = SYSCTL_ZERO,
87 .extra2 = SYSCTL_ONE,
88 },
89 { }
90};
91
92static __init int kernel_panic_sysctls_init(void)
93{
94 register_sysctl_init("kernel", kern_panic_table);
95 return 0;
96}
97late_initcall(kernel_panic_sysctls_init);
98#endif
99
100static long no_blink(int state)
101{
102 return 0;
103}
104
105
106long (*panic_blink)(int state);
107EXPORT_SYMBOL(panic_blink);
108
109
110
111
112void __weak panic_smp_self_stop(void)
113{
114 while (1)
115 cpu_relax();
116}
117
118
119
120
121
122void __weak nmi_panic_self_stop(struct pt_regs *regs)
123{
124 panic_smp_self_stop();
125}
126
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131
132
133void __weak crash_smp_send_stop(void)
134{
135 static int cpus_stopped;
136
137
138
139
140
141 if (cpus_stopped)
142 return;
143
144
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147
148
149 smp_send_stop();
150 cpus_stopped = 1;
151}
152
153atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
154
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159
160
161void nmi_panic(struct pt_regs *regs, const char *msg)
162{
163 int old_cpu, cpu;
164
165 cpu = raw_smp_processor_id();
166 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
167
168 if (old_cpu == PANIC_CPU_INVALID)
169 panic("%s", msg);
170 else if (old_cpu != cpu)
171 nmi_panic_self_stop(regs);
172}
173EXPORT_SYMBOL(nmi_panic);
174
175static void panic_print_sys_info(bool console_flush)
176{
177 if (console_flush) {
178 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
179 console_flush_on_panic(CONSOLE_REPLAY_ALL);
180 return;
181 }
182
183 if (panic_print & PANIC_PRINT_ALL_CPU_BT)
184 trigger_all_cpu_backtrace();
185
186 if (panic_print & PANIC_PRINT_TASK_INFO)
187 show_state();
188
189 if (panic_print & PANIC_PRINT_MEM_INFO)
190 show_mem(0, NULL);
191
192 if (panic_print & PANIC_PRINT_TIMER_INFO)
193 sysrq_timer_list_show();
194
195 if (panic_print & PANIC_PRINT_LOCK_INFO)
196 debug_show_all_locks();
197
198 if (panic_print & PANIC_PRINT_FTRACE_INFO)
199 ftrace_dump(DUMP_ALL);
200}
201
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208
209
210void panic(const char *fmt, ...)
211{
212 static char buf[1024];
213 va_list args;
214 long i, i_next = 0, len;
215 int state = 0;
216 int old_cpu, this_cpu;
217 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
218
219 if (panic_on_warn) {
220
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224
225
226 panic_on_warn = 0;
227 }
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234
235 local_irq_disable();
236 preempt_disable_notrace();
237
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252
253 this_cpu = raw_smp_processor_id();
254 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
255
256 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
257 panic_smp_self_stop();
258
259 console_verbose();
260 bust_spinlocks(1);
261 va_start(args, fmt);
262 len = vscnprintf(buf, sizeof(buf), fmt, args);
263 va_end(args);
264
265 if (len && buf[len - 1] == '\n')
266 buf[len - 1] = '\0';
267
268 pr_emerg("Kernel panic - not syncing: %s\n", buf);
269#ifdef CONFIG_DEBUG_BUGVERBOSE
270
271
272
273 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
274 dump_stack();
275#endif
276
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281
282 kgdb_panic(buf);
283
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291
292 if (!_crash_kexec_post_notifiers) {
293 __crash_kexec(NULL);
294
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300 smp_send_stop();
301 } else {
302
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307 crash_smp_send_stop();
308 }
309
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313
314 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
315
316 panic_print_sys_info(false);
317
318 kmsg_dump(KMSG_DUMP_PANIC);
319
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329 if (_crash_kexec_post_notifiers)
330 __crash_kexec(NULL);
331
332#ifdef CONFIG_VT
333 unblank_screen();
334#endif
335 console_unblank();
336
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344
345 debug_locks_off();
346 console_flush_on_panic(CONSOLE_FLUSH_PENDING);
347
348 panic_print_sys_info(true);
349
350 if (!panic_blink)
351 panic_blink = no_blink;
352
353 if (panic_timeout > 0) {
354
355
356
357
358 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
359
360 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
361 touch_nmi_watchdog();
362 if (i >= i_next) {
363 i += panic_blink(state ^= 1);
364 i_next = i + 3600 / PANIC_BLINK_SPD;
365 }
366 mdelay(PANIC_TIMER_STEP);
367 }
368 }
369 if (panic_timeout != 0) {
370
371
372
373
374
375 if (panic_reboot_mode != REBOOT_UNDEFINED)
376 reboot_mode = panic_reboot_mode;
377 emergency_restart();
378 }
379#ifdef __sparc__
380 {
381 extern int stop_a_enabled;
382
383 stop_a_enabled = 1;
384 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
385 "twice on console to return to the boot prom\n");
386 }
387#endif
388#if defined(CONFIG_S390)
389 disabled_wait();
390#endif
391 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
392
393
394 suppress_printk = 1;
395 local_irq_enable();
396 for (i = 0; ; i += PANIC_TIMER_STEP) {
397 touch_softlockup_watchdog();
398 if (i >= i_next) {
399 i += panic_blink(state ^= 1);
400 i_next = i + 3600 / PANIC_BLINK_SPD;
401 }
402 mdelay(PANIC_TIMER_STEP);
403 }
404}
405
406EXPORT_SYMBOL(panic);
407
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411
412const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
413 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
414 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
415 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
416 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
417 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
418 [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
419 [ TAINT_USER ] = { 'U', ' ', false },
420 [ TAINT_DIE ] = { 'D', ' ', false },
421 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
422 [ TAINT_WARN ] = { 'W', ' ', false },
423 [ TAINT_CRAP ] = { 'C', ' ', true },
424 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
425 [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
426 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
427 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
428 [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
429 [ TAINT_AUX ] = { 'X', ' ', true },
430 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
431 [ TAINT_TEST ] = { 'N', ' ', true },
432};
433
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440
441
442const char *print_tainted(void)
443{
444 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
445
446 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
447
448 if (tainted_mask) {
449 char *s;
450 int i;
451
452 s = buf + sprintf(buf, "Tainted: ");
453 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
454 const struct taint_flag *t = &taint_flags[i];
455 *s++ = test_bit(i, &tainted_mask) ?
456 t->c_true : t->c_false;
457 }
458 *s = 0;
459 } else
460 snprintf(buf, sizeof(buf), "Not tainted");
461
462 return buf;
463}
464
465int test_taint(unsigned flag)
466{
467 return test_bit(flag, &tainted_mask);
468}
469EXPORT_SYMBOL(test_taint);
470
471unsigned long get_taint(void)
472{
473 return tainted_mask;
474}
475
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482
483
484void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
485{
486 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
487 pr_warn("Disabling lock debugging due to kernel taint\n");
488
489 set_bit(flag, &tainted_mask);
490
491 if (tainted_mask & panic_on_taint) {
492 panic_on_taint = 0;
493 panic("panic_on_taint set ...");
494 }
495}
496EXPORT_SYMBOL(add_taint);
497
498static void spin_msec(int msecs)
499{
500 int i;
501
502 for (i = 0; i < msecs; i++) {
503 touch_nmi_watchdog();
504 mdelay(1);
505 }
506}
507
508
509
510
511
512static void do_oops_enter_exit(void)
513{
514 unsigned long flags;
515 static int spin_counter;
516
517 if (!pause_on_oops)
518 return;
519
520 spin_lock_irqsave(&pause_on_oops_lock, flags);
521 if (pause_on_oops_flag == 0) {
522
523 pause_on_oops_flag = 1;
524 } else {
525
526 if (!spin_counter) {
527
528 spin_counter = pause_on_oops;
529 do {
530 spin_unlock(&pause_on_oops_lock);
531 spin_msec(MSEC_PER_SEC);
532 spin_lock(&pause_on_oops_lock);
533 } while (--spin_counter);
534 pause_on_oops_flag = 0;
535 } else {
536
537 while (spin_counter) {
538 spin_unlock(&pause_on_oops_lock);
539 spin_msec(1);
540 spin_lock(&pause_on_oops_lock);
541 }
542 }
543 }
544 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
545}
546
547
548
549
550
551bool oops_may_print(void)
552{
553 return pause_on_oops_flag == 0;
554}
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570void oops_enter(void)
571{
572 tracing_off();
573
574 debug_locks_off();
575 do_oops_enter_exit();
576
577 if (sysctl_oops_all_cpu_backtrace)
578 trigger_all_cpu_backtrace();
579}
580
581static void print_oops_end_marker(void)
582{
583 pr_warn("---[ end trace %016llx ]---\n", 0ULL);
584}
585
586
587
588
589
590void oops_exit(void)
591{
592 do_oops_enter_exit();
593 print_oops_end_marker();
594 kmsg_dump(KMSG_DUMP_OOPS);
595}
596
597struct warn_args {
598 const char *fmt;
599 va_list args;
600};
601
602void __warn(const char *file, int line, void *caller, unsigned taint,
603 struct pt_regs *regs, struct warn_args *args)
604{
605 disable_trace_on_warning();
606
607 if (file)
608 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
609 raw_smp_processor_id(), current->pid, file, line,
610 caller);
611 else
612 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
613 raw_smp_processor_id(), current->pid, caller);
614
615 if (args)
616 vprintk(args->fmt, args->args);
617
618 print_modules();
619
620 if (regs)
621 show_regs(regs);
622
623 if (panic_on_warn)
624 panic("panic_on_warn set ...\n");
625
626 if (!regs)
627 dump_stack();
628
629 print_irqtrace_events(current);
630
631 print_oops_end_marker();
632 trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller);
633
634
635 add_taint(taint, LOCKDEP_STILL_OK);
636}
637
638#ifndef __WARN_FLAGS
639void warn_slowpath_fmt(const char *file, int line, unsigned taint,
640 const char *fmt, ...)
641{
642 struct warn_args args;
643
644 pr_warn(CUT_HERE);
645
646 if (!fmt) {
647 __warn(file, line, __builtin_return_address(0), taint,
648 NULL, NULL);
649 return;
650 }
651
652 args.fmt = fmt;
653 va_start(args.args, fmt);
654 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
655 va_end(args.args);
656}
657EXPORT_SYMBOL(warn_slowpath_fmt);
658#else
659void __warn_printk(const char *fmt, ...)
660{
661 va_list args;
662
663 pr_warn(CUT_HERE);
664
665 va_start(args, fmt);
666 vprintk(fmt, args);
667 va_end(args);
668}
669EXPORT_SYMBOL(__warn_printk);
670#endif
671
672#ifdef CONFIG_BUG
673
674
675
676static int clear_warn_once_set(void *data, u64 val)
677{
678 generic_bug_clear_once();
679 memset(__start_once, 0, __end_once - __start_once);
680 return 0;
681}
682
683DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
684 "%lld\n");
685
686static __init int register_warn_debugfs(void)
687{
688
689 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
690 &clear_warn_once_fops);
691 return 0;
692}
693
694device_initcall(register_warn_debugfs);
695#endif
696
697#ifdef CONFIG_STACKPROTECTOR
698
699
700
701
702
703__visible noinstr void __stack_chk_fail(void)
704{
705 instrumentation_begin();
706 panic("stack-protector: Kernel stack is corrupted in: %pB",
707 __builtin_return_address(0));
708 instrumentation_end();
709}
710EXPORT_SYMBOL(__stack_chk_fail);
711
712#endif
713
714core_param(panic, panic_timeout, int, 0644);
715core_param(panic_print, panic_print, ulong, 0644);
716core_param(pause_on_oops, pause_on_oops, int, 0644);
717core_param(panic_on_warn, panic_on_warn, int, 0644);
718core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
719
720static int __init oops_setup(char *s)
721{
722 if (!s)
723 return -EINVAL;
724 if (!strcmp(s, "panic"))
725 panic_on_oops = 1;
726 return 0;
727}
728early_param("oops", oops_setup);
729
730static int __init panic_on_taint_setup(char *s)
731{
732 char *taint_str;
733
734 if (!s)
735 return -EINVAL;
736
737 taint_str = strsep(&s, ",");
738 if (kstrtoul(taint_str, 16, &panic_on_taint))
739 return -EINVAL;
740
741
742 panic_on_taint &= TAINT_FLAGS_MAX;
743
744 if (!panic_on_taint)
745 return -EINVAL;
746
747 if (s && !strcmp(s, "nousertaint"))
748 panic_on_taint_nousertaint = true;
749
750 pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%sabled\n",
751 panic_on_taint, panic_on_taint_nousertaint ? "en" : "dis");
752
753 return 0;
754}
755early_param("panic_on_taint", panic_on_taint_setup);
756