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12#include <linux/debug_locks.h>
13#include <linux/sched/debug.h>
14#include <linux/interrupt.h>
15#include <linux/kmsg_dump.h>
16#include <linux/kallsyms.h>
17#include <linux/notifier.h>
18#include <linux/vt_kern.h>
19#include <linux/module.h>
20#include <linux/random.h>
21#include <linux/ftrace.h>
22#include <linux/reboot.h>
23#include <linux/delay.h>
24#include <linux/kexec.h>
25#include <linux/sched.h>
26#include <linux/sysrq.h>
27#include <linux/init.h>
28#include <linux/nmi.h>
29#include <linux/console.h>
30#include <linux/bug.h>
31#include <linux/ratelimit.h>
32#include <linux/debugfs.h>
33#include <asm/sections.h>
34
35#define PANIC_TIMER_STEP 100
36#define PANIC_BLINK_SPD 18
37
38int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
39static unsigned long tainted_mask =
40 IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
41static int pause_on_oops;
42static int pause_on_oops_flag;
43static DEFINE_SPINLOCK(pause_on_oops_lock);
44bool crash_kexec_post_notifiers;
45int panic_on_warn __read_mostly;
46
47int panic_timeout = CONFIG_PANIC_TIMEOUT;
48EXPORT_SYMBOL_GPL(panic_timeout);
49
50#define PANIC_PRINT_TASK_INFO 0x00000001
51#define PANIC_PRINT_MEM_INFO 0x00000002
52#define PANIC_PRINT_TIMER_INFO 0x00000004
53#define PANIC_PRINT_LOCK_INFO 0x00000008
54#define PANIC_PRINT_FTRACE_INFO 0x00000010
55#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020
56unsigned long panic_print;
57
58ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
59
60EXPORT_SYMBOL(panic_notifier_list);
61
62static long no_blink(int state)
63{
64 return 0;
65}
66
67
68long (*panic_blink)(int state);
69EXPORT_SYMBOL(panic_blink);
70
71
72
73
74void __weak panic_smp_self_stop(void)
75{
76 while (1)
77 cpu_relax();
78}
79
80
81
82
83
84void __weak nmi_panic_self_stop(struct pt_regs *regs)
85{
86 panic_smp_self_stop();
87}
88
89
90
91
92
93
94
95void __weak crash_smp_send_stop(void)
96{
97 static int cpus_stopped;
98
99
100
101
102
103 if (cpus_stopped)
104 return;
105
106
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108
109
110
111 smp_send_stop();
112 cpus_stopped = 1;
113}
114
115atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
116
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120
121
122
123void nmi_panic(struct pt_regs *regs, const char *msg)
124{
125 int old_cpu, cpu;
126
127 cpu = raw_smp_processor_id();
128 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
129
130 if (old_cpu == PANIC_CPU_INVALID)
131 panic("%s", msg);
132 else if (old_cpu != cpu)
133 nmi_panic_self_stop(regs);
134}
135EXPORT_SYMBOL(nmi_panic);
136
137static void panic_print_sys_info(void)
138{
139 if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
140 console_flush_on_panic(CONSOLE_REPLAY_ALL);
141
142 if (panic_print & PANIC_PRINT_TASK_INFO)
143 show_state();
144
145 if (panic_print & PANIC_PRINT_MEM_INFO)
146 show_mem(0, NULL);
147
148 if (panic_print & PANIC_PRINT_TIMER_INFO)
149 sysrq_timer_list_show();
150
151 if (panic_print & PANIC_PRINT_LOCK_INFO)
152 debug_show_all_locks();
153
154 if (panic_print & PANIC_PRINT_FTRACE_INFO)
155 ftrace_dump(DUMP_ALL);
156}
157
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164
165
166void panic(const char *fmt, ...)
167{
168 static char buf[1024];
169 va_list args;
170 long i, i_next = 0, len;
171 int state = 0;
172 int old_cpu, this_cpu;
173 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
174
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180
181 local_irq_disable();
182
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197
198 this_cpu = raw_smp_processor_id();
199 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
200
201 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
202 panic_smp_self_stop();
203
204 console_verbose();
205 bust_spinlocks(1);
206 va_start(args, fmt);
207 len = vscnprintf(buf, sizeof(buf), fmt, args);
208 va_end(args);
209
210 if (len && buf[len - 1] == '\n')
211 buf[len - 1] = '\0';
212
213 pr_emerg("Kernel panic - not syncing: %s\n", buf);
214#ifdef CONFIG_DEBUG_BUGVERBOSE
215
216
217
218 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
219 dump_stack();
220#endif
221
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229
230 if (!_crash_kexec_post_notifiers) {
231 printk_safe_flush_on_panic();
232 __crash_kexec(NULL);
233
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238
239 smp_send_stop();
240 } else {
241
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245
246 crash_smp_send_stop();
247 }
248
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252
253 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
254
255
256 printk_safe_flush_on_panic();
257 kmsg_dump(KMSG_DUMP_PANIC);
258
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267
268 if (_crash_kexec_post_notifiers)
269 __crash_kexec(NULL);
270
271#ifdef CONFIG_VT
272 unblank_screen();
273#endif
274 console_unblank();
275
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283
284 debug_locks_off();
285 console_flush_on_panic(CONSOLE_FLUSH_PENDING);
286
287 panic_print_sys_info();
288
289 if (!panic_blink)
290 panic_blink = no_blink;
291
292 if (panic_timeout > 0) {
293
294
295
296
297 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
298
299 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
300 touch_nmi_watchdog();
301 if (i >= i_next) {
302 i += panic_blink(state ^= 1);
303 i_next = i + 3600 / PANIC_BLINK_SPD;
304 }
305 mdelay(PANIC_TIMER_STEP);
306 }
307 }
308 if (panic_timeout != 0) {
309
310
311
312
313
314 if (panic_reboot_mode != REBOOT_UNDEFINED)
315 reboot_mode = panic_reboot_mode;
316 emergency_restart();
317 }
318#ifdef __sparc__
319 {
320 extern int stop_a_enabled;
321
322 stop_a_enabled = 1;
323 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
324 "twice on console to return to the boot prom\n");
325 }
326#endif
327#if defined(CONFIG_S390)
328 disabled_wait();
329#endif
330 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
331
332
333 suppress_printk = 1;
334 local_irq_enable();
335 for (i = 0; ; i += PANIC_TIMER_STEP) {
336 touch_softlockup_watchdog();
337 if (i >= i_next) {
338 i += panic_blink(state ^= 1);
339 i_next = i + 3600 / PANIC_BLINK_SPD;
340 }
341 mdelay(PANIC_TIMER_STEP);
342 }
343}
344
345EXPORT_SYMBOL(panic);
346
347
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349
350
351const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
352 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
353 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
354 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
355 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
356 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
357 [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
358 [ TAINT_USER ] = { 'U', ' ', false },
359 [ TAINT_DIE ] = { 'D', ' ', false },
360 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
361 [ TAINT_WARN ] = { 'W', ' ', false },
362 [ TAINT_CRAP ] = { 'C', ' ', true },
363 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
364 [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
365 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
366 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
367 [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
368 [ TAINT_AUX ] = { 'X', ' ', true },
369 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
370};
371
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375
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377
378
379
380const char *print_tainted(void)
381{
382 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
383
384 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
385
386 if (tainted_mask) {
387 char *s;
388 int i;
389
390 s = buf + sprintf(buf, "Tainted: ");
391 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
392 const struct taint_flag *t = &taint_flags[i];
393 *s++ = test_bit(i, &tainted_mask) ?
394 t->c_true : t->c_false;
395 }
396 *s = 0;
397 } else
398 snprintf(buf, sizeof(buf), "Not tainted");
399
400 return buf;
401}
402
403int test_taint(unsigned flag)
404{
405 return test_bit(flag, &tainted_mask);
406}
407EXPORT_SYMBOL(test_taint);
408
409unsigned long get_taint(void)
410{
411 return tainted_mask;
412}
413
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420
421
422void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
423{
424 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
425 pr_warn("Disabling lock debugging due to kernel taint\n");
426
427 set_bit(flag, &tainted_mask);
428}
429EXPORT_SYMBOL(add_taint);
430
431static void spin_msec(int msecs)
432{
433 int i;
434
435 for (i = 0; i < msecs; i++) {
436 touch_nmi_watchdog();
437 mdelay(1);
438 }
439}
440
441
442
443
444
445static void do_oops_enter_exit(void)
446{
447 unsigned long flags;
448 static int spin_counter;
449
450 if (!pause_on_oops)
451 return;
452
453 spin_lock_irqsave(&pause_on_oops_lock, flags);
454 if (pause_on_oops_flag == 0) {
455
456 pause_on_oops_flag = 1;
457 } else {
458
459 if (!spin_counter) {
460
461 spin_counter = pause_on_oops;
462 do {
463 spin_unlock(&pause_on_oops_lock);
464 spin_msec(MSEC_PER_SEC);
465 spin_lock(&pause_on_oops_lock);
466 } while (--spin_counter);
467 pause_on_oops_flag = 0;
468 } else {
469
470 while (spin_counter) {
471 spin_unlock(&pause_on_oops_lock);
472 spin_msec(1);
473 spin_lock(&pause_on_oops_lock);
474 }
475 }
476 }
477 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
478}
479
480
481
482
483
484int oops_may_print(void)
485{
486 return pause_on_oops_flag == 0;
487}
488
489
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494
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497
498
499
500
501
502
503void oops_enter(void)
504{
505 tracing_off();
506
507 debug_locks_off();
508 do_oops_enter_exit();
509}
510
511
512
513
514static u64 oops_id;
515
516static int init_oops_id(void)
517{
518 if (!oops_id)
519 get_random_bytes(&oops_id, sizeof(oops_id));
520 else
521 oops_id++;
522
523 return 0;
524}
525late_initcall(init_oops_id);
526
527void print_oops_end_marker(void)
528{
529 init_oops_id();
530 pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
531}
532
533
534
535
536
537void oops_exit(void)
538{
539 do_oops_enter_exit();
540 print_oops_end_marker();
541 kmsg_dump(KMSG_DUMP_OOPS);
542}
543
544struct warn_args {
545 const char *fmt;
546 va_list args;
547};
548
549void __warn(const char *file, int line, void *caller, unsigned taint,
550 struct pt_regs *regs, struct warn_args *args)
551{
552 disable_trace_on_warning();
553
554 if (args)
555 pr_warn(CUT_HERE);
556
557 if (file)
558 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
559 raw_smp_processor_id(), current->pid, file, line,
560 caller);
561 else
562 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
563 raw_smp_processor_id(), current->pid, caller);
564
565 if (args)
566 vprintk(args->fmt, args->args);
567
568 if (panic_on_warn) {
569
570
571
572
573
574
575 panic_on_warn = 0;
576 panic("panic_on_warn set ...\n");
577 }
578
579 print_modules();
580
581 if (regs)
582 show_regs(regs);
583 else
584 dump_stack();
585
586 print_irqtrace_events(current);
587
588 print_oops_end_marker();
589
590
591 add_taint(taint, LOCKDEP_STILL_OK);
592}
593
594#ifdef WANT_WARN_ON_SLOWPATH
595void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
596{
597 struct warn_args args;
598
599 args.fmt = fmt;
600 va_start(args.args, fmt);
601 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL,
602 &args);
603 va_end(args.args);
604}
605EXPORT_SYMBOL(warn_slowpath_fmt);
606
607void warn_slowpath_fmt_taint(const char *file, int line,
608 unsigned taint, const char *fmt, ...)
609{
610 struct warn_args args;
611
612 args.fmt = fmt;
613 va_start(args.args, fmt);
614 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
615 va_end(args.args);
616}
617EXPORT_SYMBOL(warn_slowpath_fmt_taint);
618
619void warn_slowpath_null(const char *file, int line)
620{
621 pr_warn(CUT_HERE);
622 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL);
623}
624EXPORT_SYMBOL(warn_slowpath_null);
625#else
626void __warn_printk(const char *fmt, ...)
627{
628 va_list args;
629
630 pr_warn(CUT_HERE);
631
632 va_start(args, fmt);
633 vprintk(fmt, args);
634 va_end(args);
635}
636EXPORT_SYMBOL(__warn_printk);
637#endif
638
639#ifdef CONFIG_BUG
640
641
642
643static int clear_warn_once_set(void *data, u64 val)
644{
645 generic_bug_clear_once();
646 memset(__start_once, 0, __end_once - __start_once);
647 return 0;
648}
649
650DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
651 "%lld\n");
652
653static __init int register_warn_debugfs(void)
654{
655
656 debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
657 &clear_warn_once_fops);
658 return 0;
659}
660
661device_initcall(register_warn_debugfs);
662#endif
663
664#ifdef CONFIG_STACKPROTECTOR
665
666
667
668
669
670__visible void __stack_chk_fail(void)
671{
672 panic("stack-protector: Kernel stack is corrupted in: %pB",
673 __builtin_return_address(0));
674}
675EXPORT_SYMBOL(__stack_chk_fail);
676
677#endif
678
679#ifdef CONFIG_ARCH_HAS_REFCOUNT
680void refcount_error_report(struct pt_regs *regs, const char *err)
681{
682 WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n",
683 err, (void *)instruction_pointer(regs),
684 current->comm, task_pid_nr(current),
685 from_kuid_munged(&init_user_ns, current_uid()),
686 from_kuid_munged(&init_user_ns, current_euid()));
687}
688#endif
689
690core_param(panic, panic_timeout, int, 0644);
691core_param(panic_print, panic_print, ulong, 0644);
692core_param(pause_on_oops, pause_on_oops, int, 0644);
693core_param(panic_on_warn, panic_on_warn, int, 0644);
694core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
695
696static int __init oops_setup(char *s)
697{
698 if (!s)
699 return -EINVAL;
700 if (!strcmp(s, "panic"))
701 panic_on_oops = 1;
702 return 0;
703}
704early_param("oops", oops_setup);
705