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