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11#include <linux/debug_locks.h>
12#include <linux/sched/debug.h>
13#include <linux/interrupt.h>
14#include <linux/kmsg_dump.h>
15#include <linux/kallsyms.h>
16#include <linux/notifier.h>
17#include <linux/module.h>
18#include <linux/random.h>
19#include <linux/ftrace.h>
20#include <linux/reboot.h>
21#include <linux/delay.h>
22#include <linux/kexec.h>
23#include <linux/sched.h>
24#include <linux/sysrq.h>
25#include <linux/init.h>
26#include <linux/nmi.h>
27#include <linux/console.h>
28#include <linux/bug.h>
29#include <linux/ratelimit.h>
30#include <linux/debugfs.h>
31#include <asm/sections.h>
32
33#define PANIC_TIMER_STEP 100
34#define PANIC_BLINK_SPD 18
35
36int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
37static unsigned long tainted_mask =
38 IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
39static int pause_on_oops;
40static int pause_on_oops_flag;
41static DEFINE_SPINLOCK(pause_on_oops_lock);
42bool crash_kexec_post_notifiers;
43int panic_on_warn __read_mostly;
44
45int panic_timeout = CONFIG_PANIC_TIMEOUT;
46EXPORT_SYMBOL_GPL(panic_timeout);
47
48ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
49
50EXPORT_SYMBOL(panic_notifier_list);
51
52static long no_blink(int state)
53{
54 return 0;
55}
56
57
58long (*panic_blink)(int state);
59EXPORT_SYMBOL(panic_blink);
60
61
62
63
64void __weak panic_smp_self_stop(void)
65{
66 while (1)
67 cpu_relax();
68}
69
70
71
72
73
74void __weak nmi_panic_self_stop(struct pt_regs *regs)
75{
76 panic_smp_self_stop();
77}
78
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83
84
85void __weak crash_smp_send_stop(void)
86{
87 static int cpus_stopped;
88
89
90
91
92
93 if (cpus_stopped)
94 return;
95
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99
100
101 smp_send_stop();
102 cpus_stopped = 1;
103}
104
105atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
106
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110
111
112
113void nmi_panic(struct pt_regs *regs, const char *msg)
114{
115 int old_cpu, cpu;
116
117 cpu = raw_smp_processor_id();
118 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
119
120 if (old_cpu == PANIC_CPU_INVALID)
121 panic("%s", msg);
122 else if (old_cpu != cpu)
123 nmi_panic_self_stop(regs);
124}
125EXPORT_SYMBOL(nmi_panic);
126
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132
133
134
135void panic(const char *fmt, ...)
136{
137 static char buf[1024];
138 va_list args;
139 long i, i_next = 0;
140 int state = 0;
141 int old_cpu, this_cpu;
142 bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
143
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149
150 local_irq_disable();
151
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166
167 this_cpu = raw_smp_processor_id();
168 old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
169
170 if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
171 panic_smp_self_stop();
172
173 console_verbose();
174 bust_spinlocks(1);
175 va_start(args, fmt);
176 vsnprintf(buf, sizeof(buf), fmt, args);
177 va_end(args);
178 pr_emerg("Kernel panic - not syncing: %s\n", buf);
179#ifdef CONFIG_DEBUG_BUGVERBOSE
180
181
182
183 if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
184 dump_stack();
185#endif
186
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194
195 if (!_crash_kexec_post_notifiers) {
196 printk_safe_flush_on_panic();
197 __crash_kexec(NULL);
198
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203
204 smp_send_stop();
205 } else {
206
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210
211 crash_smp_send_stop();
212 }
213
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217
218 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
219
220
221 printk_safe_flush_on_panic();
222 kmsg_dump(KMSG_DUMP_PANIC);
223
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232
233 if (_crash_kexec_post_notifiers)
234 __crash_kexec(NULL);
235
236 bust_spinlocks(0);
237
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245
246 debug_locks_off();
247 console_flush_on_panic();
248
249 if (!panic_blink)
250 panic_blink = no_blink;
251
252 if (panic_timeout > 0) {
253
254
255
256
257 pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
258
259 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
260 touch_nmi_watchdog();
261 if (i >= i_next) {
262 i += panic_blink(state ^= 1);
263 i_next = i + 3600 / PANIC_BLINK_SPD;
264 }
265 mdelay(PANIC_TIMER_STEP);
266 }
267 }
268 if (panic_timeout != 0) {
269
270
271
272
273
274 emergency_restart();
275 }
276#ifdef __sparc__
277 {
278 extern int stop_a_enabled;
279
280 stop_a_enabled = 1;
281 pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
282 "twice on console to return to the boot prom\n");
283 }
284#endif
285#if defined(CONFIG_S390)
286 {
287 unsigned long caller;
288
289 caller = (unsigned long)__builtin_return_address(0);
290 disabled_wait(caller);
291 }
292#endif
293 pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
294 local_irq_enable();
295 for (i = 0; ; i += PANIC_TIMER_STEP) {
296 touch_softlockup_watchdog();
297 if (i >= i_next) {
298 i += panic_blink(state ^= 1);
299 i_next = i + 3600 / PANIC_BLINK_SPD;
300 }
301 mdelay(PANIC_TIMER_STEP);
302 }
303}
304
305EXPORT_SYMBOL(panic);
306
307
308
309
310
311const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
312 [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
313 [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
314 [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
315 [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
316 [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
317 [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
318 [ TAINT_USER ] = { 'U', ' ', false },
319 [ TAINT_DIE ] = { 'D', ' ', false },
320 [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
321 [ TAINT_WARN ] = { 'W', ' ', false },
322 [ TAINT_CRAP ] = { 'C', ' ', true },
323 [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
324 [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
325 [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
326 [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
327 [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
328 [ TAINT_AUX ] = { 'X', ' ', true },
329 [ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
330};
331
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337
338
339
340const char *print_tainted(void)
341{
342 static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
343
344 BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
345
346 if (tainted_mask) {
347 char *s;
348 int i;
349
350 s = buf + sprintf(buf, "Tainted: ");
351 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
352 const struct taint_flag *t = &taint_flags[i];
353 *s++ = test_bit(i, &tainted_mask) ?
354 t->c_true : t->c_false;
355 }
356 *s = 0;
357 } else
358 snprintf(buf, sizeof(buf), "Not tainted");
359
360 return buf;
361}
362
363int test_taint(unsigned flag)
364{
365 return test_bit(flag, &tainted_mask);
366}
367EXPORT_SYMBOL(test_taint);
368
369unsigned long get_taint(void)
370{
371 return tainted_mask;
372}
373
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380
381
382void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
383{
384 if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
385 pr_warn("Disabling lock debugging due to kernel taint\n");
386
387 set_bit(flag, &tainted_mask);
388}
389EXPORT_SYMBOL(add_taint);
390
391static void spin_msec(int msecs)
392{
393 int i;
394
395 for (i = 0; i < msecs; i++) {
396 touch_nmi_watchdog();
397 mdelay(1);
398 }
399}
400
401
402
403
404
405static void do_oops_enter_exit(void)
406{
407 unsigned long flags;
408 static int spin_counter;
409
410 if (!pause_on_oops)
411 return;
412
413 spin_lock_irqsave(&pause_on_oops_lock, flags);
414 if (pause_on_oops_flag == 0) {
415
416 pause_on_oops_flag = 1;
417 } else {
418
419 if (!spin_counter) {
420
421 spin_counter = pause_on_oops;
422 do {
423 spin_unlock(&pause_on_oops_lock);
424 spin_msec(MSEC_PER_SEC);
425 spin_lock(&pause_on_oops_lock);
426 } while (--spin_counter);
427 pause_on_oops_flag = 0;
428 } else {
429
430 while (spin_counter) {
431 spin_unlock(&pause_on_oops_lock);
432 spin_msec(1);
433 spin_lock(&pause_on_oops_lock);
434 }
435 }
436 }
437 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
438}
439
440
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442
443
444int oops_may_print(void)
445{
446 return pause_on_oops_flag == 0;
447}
448
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460
461
462
463void oops_enter(void)
464{
465 tracing_off();
466
467 debug_locks_off();
468 do_oops_enter_exit();
469}
470
471
472
473
474static u64 oops_id;
475
476static int init_oops_id(void)
477{
478 if (!oops_id)
479 get_random_bytes(&oops_id, sizeof(oops_id));
480 else
481 oops_id++;
482
483 return 0;
484}
485late_initcall(init_oops_id);
486
487void print_oops_end_marker(void)
488{
489 init_oops_id();
490 pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
491}
492
493
494
495
496
497void oops_exit(void)
498{
499 do_oops_enter_exit();
500 print_oops_end_marker();
501 kmsg_dump(KMSG_DUMP_OOPS);
502}
503
504struct warn_args {
505 const char *fmt;
506 va_list args;
507};
508
509void __warn(const char *file, int line, void *caller, unsigned taint,
510 struct pt_regs *regs, struct warn_args *args)
511{
512 disable_trace_on_warning();
513
514 if (args)
515 pr_warn(CUT_HERE);
516
517 if (file)
518 pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
519 raw_smp_processor_id(), current->pid, file, line,
520 caller);
521 else
522 pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
523 raw_smp_processor_id(), current->pid, caller);
524
525 if (args)
526 vprintk(args->fmt, args->args);
527
528 if (panic_on_warn) {
529
530
531
532
533
534
535 panic_on_warn = 0;
536 panic("panic_on_warn set ...\n");
537 }
538
539 print_modules();
540
541 if (regs)
542 show_regs(regs);
543 else
544 dump_stack();
545
546 print_irqtrace_events(current);
547
548 print_oops_end_marker();
549
550
551 add_taint(taint, LOCKDEP_STILL_OK);
552}
553
554#ifdef WANT_WARN_ON_SLOWPATH
555void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
556{
557 struct warn_args args;
558
559 args.fmt = fmt;
560 va_start(args.args, fmt);
561 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL,
562 &args);
563 va_end(args.args);
564}
565EXPORT_SYMBOL(warn_slowpath_fmt);
566
567void warn_slowpath_fmt_taint(const char *file, int line,
568 unsigned taint, const char *fmt, ...)
569{
570 struct warn_args args;
571
572 args.fmt = fmt;
573 va_start(args.args, fmt);
574 __warn(file, line, __builtin_return_address(0), taint, NULL, &args);
575 va_end(args.args);
576}
577EXPORT_SYMBOL(warn_slowpath_fmt_taint);
578
579void warn_slowpath_null(const char *file, int line)
580{
581 pr_warn(CUT_HERE);
582 __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL);
583}
584EXPORT_SYMBOL(warn_slowpath_null);
585#else
586void __warn_printk(const char *fmt, ...)
587{
588 va_list args;
589
590 pr_warn(CUT_HERE);
591
592 va_start(args, fmt);
593 vprintk(fmt, args);
594 va_end(args);
595}
596EXPORT_SYMBOL(__warn_printk);
597#endif
598
599#ifdef CONFIG_BUG
600
601
602
603static int clear_warn_once_set(void *data, u64 val)
604{
605 generic_bug_clear_once();
606 memset(__start_once, 0, __end_once - __start_once);
607 return 0;
608}
609
610DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops,
611 NULL,
612 clear_warn_once_set,
613 "%lld\n");
614
615static __init int register_warn_debugfs(void)
616{
617
618 debugfs_create_file("clear_warn_once", 0200, NULL,
619 NULL, &clear_warn_once_fops);
620 return 0;
621}
622
623device_initcall(register_warn_debugfs);
624#endif
625
626#ifdef CONFIG_CC_STACKPROTECTOR
627
628
629
630
631
632__visible void __stack_chk_fail(void)
633{
634 panic("stack-protector: Kernel stack is corrupted in: %pB\n",
635 __builtin_return_address(0));
636}
637EXPORT_SYMBOL(__stack_chk_fail);
638
639#endif
640
641#ifdef CONFIG_ARCH_HAS_REFCOUNT
642void refcount_error_report(struct pt_regs *regs, const char *err)
643{
644 WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n",
645 err, (void *)instruction_pointer(regs),
646 current->comm, task_pid_nr(current),
647 from_kuid_munged(&init_user_ns, current_uid()),
648 from_kuid_munged(&init_user_ns, current_euid()));
649}
650#endif
651
652core_param(panic, panic_timeout, int, 0644);
653core_param(pause_on_oops, pause_on_oops, int, 0644);
654core_param(panic_on_warn, panic_on_warn, int, 0644);
655core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
656
657static int __init oops_setup(char *s)
658{
659 if (!s)
660 return -EINVAL;
661 if (!strcmp(s, "panic"))
662 panic_on_oops = 1;
663 return 0;
664}
665early_param("oops", oops_setup);
666