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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/sched.h> | |
27 | #include <linux/sysrq.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/nmi.h> | |
30 | #include <linux/console.h> | |
31 | #include <linux/bug.h> | |
32 | #include <linux/ratelimit.h> | |
33 | #include <linux/debugfs.h> | |
34 | #include <asm/sections.h> | |
35 | ||
36 | #define PANIC_TIMER_STEP 100 | |
37 | #define PANIC_BLINK_SPD 18 | |
38 | ||
39 | #ifdef CONFIG_SMP | |
40 | /* | |
41 | * Should we dump all CPUs backtraces in an oops event? | |
42 | * Defaults to 0, can be changed via sysctl. | |
43 | */ | |
44 | unsigned int __read_mostly sysctl_oops_all_cpu_backtrace; | |
45 | #endif /* CONFIG_SMP */ | |
46 | ||
47 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; | |
48 | static unsigned long tainted_mask = | |
49 | IS_ENABLED(CONFIG_GCC_PLUGIN_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0; | |
50 | static int pause_on_oops; | |
51 | static int pause_on_oops_flag; | |
52 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
53 | bool crash_kexec_post_notifiers; | |
54 | int panic_on_warn __read_mostly; | |
55 | unsigned long panic_on_taint; | |
56 | bool panic_on_taint_nousertaint = false; | |
57 | ||
58 | int panic_timeout = CONFIG_PANIC_TIMEOUT; | |
59 | EXPORT_SYMBOL_GPL(panic_timeout); | |
60 | ||
61 | #define PANIC_PRINT_TASK_INFO 0x00000001 | |
62 | #define PANIC_PRINT_MEM_INFO 0x00000002 | |
63 | #define PANIC_PRINT_TIMER_INFO 0x00000004 | |
64 | #define PANIC_PRINT_LOCK_INFO 0x00000008 | |
65 | #define PANIC_PRINT_FTRACE_INFO 0x00000010 | |
66 | #define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020 | |
67 | unsigned long panic_print; | |
68 | ||
69 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); | |
70 | ||
71 | EXPORT_SYMBOL(panic_notifier_list); | |
72 | ||
73 | static long no_blink(int state) | |
74 | { | |
75 | return 0; | |
76 | } | |
77 | ||
78 | /* Returns how long it waited in ms */ | |
79 | long (*panic_blink)(int state); | |
80 | EXPORT_SYMBOL(panic_blink); | |
81 | ||
82 | /* | |
83 | * Stop ourself in panic -- architecture code may override this | |
84 | */ | |
85 | void __weak panic_smp_self_stop(void) | |
86 | { | |
87 | while (1) | |
88 | cpu_relax(); | |
89 | } | |
90 | ||
91 | /* | |
92 | * Stop ourselves in NMI context if another CPU has already panicked. Arch code | |
93 | * may override this to prepare for crash dumping, e.g. save regs info. | |
94 | */ | |
95 | void __weak nmi_panic_self_stop(struct pt_regs *regs) | |
96 | { | |
97 | panic_smp_self_stop(); | |
98 | } | |
99 | ||
100 | /* | |
101 | * Stop other CPUs in panic. Architecture dependent code may override this | |
102 | * with more suitable version. For example, if the architecture supports | |
103 | * crash dump, it should save registers of each stopped CPU and disable | |
104 | * per-CPU features such as virtualization extensions. | |
105 | */ | |
106 | void __weak crash_smp_send_stop(void) | |
107 | { | |
108 | static int cpus_stopped; | |
109 | ||
110 | /* | |
111 | * This function can be called twice in panic path, but obviously | |
112 | * we execute this only once. | |
113 | */ | |
114 | if (cpus_stopped) | |
115 | return; | |
116 | ||
117 | /* | |
118 | * Note smp_send_stop is the usual smp shutdown function, which | |
119 | * unfortunately means it may not be hardened to work in a panic | |
120 | * situation. | |
121 | */ | |
122 | smp_send_stop(); | |
123 | cpus_stopped = 1; | |
124 | } | |
125 | ||
126 | atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID); | |
127 | ||
128 | /* | |
129 | * A variant of panic() called from NMI context. We return if we've already | |
130 | * panicked on this CPU. If another CPU already panicked, loop in | |
131 | * nmi_panic_self_stop() which can provide architecture dependent code such | |
132 | * as saving register state for crash dump. | |
133 | */ | |
134 | void nmi_panic(struct pt_regs *regs, const char *msg) | |
135 | { | |
136 | int old_cpu, cpu; | |
137 | ||
138 | cpu = raw_smp_processor_id(); | |
139 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); | |
140 | ||
141 | if (old_cpu == PANIC_CPU_INVALID) | |
142 | panic("%s", msg); | |
143 | else if (old_cpu != cpu) | |
144 | nmi_panic_self_stop(regs); | |
145 | } | |
146 | EXPORT_SYMBOL(nmi_panic); | |
147 | ||
148 | static void panic_print_sys_info(void) | |
149 | { | |
150 | if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG) | |
151 | console_flush_on_panic(CONSOLE_REPLAY_ALL); | |
152 | ||
153 | if (panic_print & PANIC_PRINT_TASK_INFO) | |
154 | show_state(); | |
155 | ||
156 | if (panic_print & PANIC_PRINT_MEM_INFO) | |
157 | show_mem(0, NULL); | |
158 | ||
159 | if (panic_print & PANIC_PRINT_TIMER_INFO) | |
160 | sysrq_timer_list_show(); | |
161 | ||
162 | if (panic_print & PANIC_PRINT_LOCK_INFO) | |
163 | debug_show_all_locks(); | |
164 | ||
165 | if (panic_print & PANIC_PRINT_FTRACE_INFO) | |
166 | ftrace_dump(DUMP_ALL); | |
167 | } | |
168 | ||
169 | /** | |
170 | * panic - halt the system | |
171 | * @fmt: The text string to print | |
172 | * | |
173 | * Display a message, then perform cleanups. | |
174 | * | |
175 | * This function never returns. | |
176 | */ | |
177 | void panic(const char *fmt, ...) | |
178 | { | |
179 | static char buf[1024]; | |
180 | va_list args; | |
181 | long i, i_next = 0, len; | |
182 | int state = 0; | |
183 | int old_cpu, this_cpu; | |
184 | bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers; | |
185 | ||
186 | /* | |
187 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
188 | * from deadlocking the first cpu that invokes the panic, since | |
189 | * there is nothing to prevent an interrupt handler (that runs | |
190 | * after setting panic_cpu) from invoking panic() again. | |
191 | */ | |
192 | local_irq_disable(); | |
193 | preempt_disable_notrace(); | |
194 | ||
195 | /* | |
196 | * It's possible to come here directly from a panic-assertion and | |
197 | * not have preempt disabled. Some functions called from here want | |
198 | * preempt to be disabled. No point enabling it later though... | |
199 | * | |
200 | * Only one CPU is allowed to execute the panic code from here. For | |
201 | * multiple parallel invocations of panic, all other CPUs either | |
202 | * stop themself or will wait until they are stopped by the 1st CPU | |
203 | * with smp_send_stop(). | |
204 | * | |
205 | * `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which | |
206 | * comes here, so go ahead. | |
207 | * `old_cpu == this_cpu' means we came from nmi_panic() which sets | |
208 | * panic_cpu to this CPU. In this case, this is also the 1st CPU. | |
209 | */ | |
210 | this_cpu = raw_smp_processor_id(); | |
211 | old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); | |
212 | ||
213 | if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu) | |
214 | panic_smp_self_stop(); | |
215 | ||
216 | console_verbose(); | |
217 | bust_spinlocks(1); | |
218 | va_start(args, fmt); | |
219 | len = vscnprintf(buf, sizeof(buf), fmt, args); | |
220 | va_end(args); | |
221 | ||
222 | if (len && buf[len - 1] == '\n') | |
223 | buf[len - 1] = '\0'; | |
224 | ||
225 | pr_emerg("Kernel panic - not syncing: %s\n", buf); | |
226 | #ifdef CONFIG_DEBUG_BUGVERBOSE | |
227 | /* | |
228 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
229 | */ | |
230 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) | |
231 | dump_stack(); | |
232 | #endif | |
233 | ||
234 | /* | |
235 | * If kgdb is enabled, give it a chance to run before we stop all | |
236 | * the other CPUs or else we won't be able to debug processes left | |
237 | * running on them. | |
238 | */ | |
239 | kgdb_panic(buf); | |
240 | ||
241 | /* | |
242 | * If we have crashed and we have a crash kernel loaded let it handle | |
243 | * everything else. | |
244 | * If we want to run this after calling panic_notifiers, pass | |
245 | * the "crash_kexec_post_notifiers" option to the kernel. | |
246 | * | |
247 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
248 | */ | |
249 | if (!_crash_kexec_post_notifiers) { | |
250 | printk_safe_flush_on_panic(); | |
251 | __crash_kexec(NULL); | |
252 | ||
253 | /* | |
254 | * Note smp_send_stop is the usual smp shutdown function, which | |
255 | * unfortunately means it may not be hardened to work in a | |
256 | * panic situation. | |
257 | */ | |
258 | smp_send_stop(); | |
259 | } else { | |
260 | /* | |
261 | * If we want to do crash dump after notifier calls and | |
262 | * kmsg_dump, we will need architecture dependent extra | |
263 | * works in addition to stopping other CPUs. | |
264 | */ | |
265 | crash_smp_send_stop(); | |
266 | } | |
267 | ||
268 | /* | |
269 | * Run any panic handlers, including those that might need to | |
270 | * add information to the kmsg dump output. | |
271 | */ | |
272 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); | |
273 | ||
274 | /* Call flush even twice. It tries harder with a single online CPU */ | |
275 | printk_safe_flush_on_panic(); | |
276 | kmsg_dump(KMSG_DUMP_PANIC); | |
277 | ||
278 | /* | |
279 | * If you doubt kdump always works fine in any situation, | |
280 | * "crash_kexec_post_notifiers" offers you a chance to run | |
281 | * panic_notifiers and dumping kmsg before kdump. | |
282 | * Note: since some panic_notifiers can make crashed kernel | |
283 | * more unstable, it can increase risks of the kdump failure too. | |
284 | * | |
285 | * Bypass the panic_cpu check and call __crash_kexec directly. | |
286 | */ | |
287 | if (_crash_kexec_post_notifiers) | |
288 | __crash_kexec(NULL); | |
289 | ||
290 | #ifdef CONFIG_VT | |
291 | unblank_screen(); | |
292 | #endif | |
293 | console_unblank(); | |
294 | ||
295 | /* | |
296 | * We may have ended up stopping the CPU holding the lock (in | |
297 | * smp_send_stop()) while still having some valuable data in the console | |
298 | * buffer. Try to acquire the lock then release it regardless of the | |
299 | * result. The release will also print the buffers out. Locks debug | |
300 | * should be disabled to avoid reporting bad unlock balance when | |
301 | * panic() is not being callled from OOPS. | |
302 | */ | |
303 | debug_locks_off(); | |
304 | console_flush_on_panic(CONSOLE_FLUSH_PENDING); | |
305 | ||
306 | panic_print_sys_info(); | |
307 | ||
308 | if (!panic_blink) | |
309 | panic_blink = no_blink; | |
310 | ||
311 | if (panic_timeout > 0) { | |
312 | /* | |
313 | * Delay timeout seconds before rebooting the machine. | |
314 | * We can't use the "normal" timers since we just panicked. | |
315 | */ | |
316 | pr_emerg("Rebooting in %d seconds..\n", panic_timeout); | |
317 | ||
318 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { | |
319 | touch_nmi_watchdog(); | |
320 | if (i >= i_next) { | |
321 | i += panic_blink(state ^= 1); | |
322 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
323 | } | |
324 | mdelay(PANIC_TIMER_STEP); | |
325 | } | |
326 | } | |
327 | if (panic_timeout != 0) { | |
328 | /* | |
329 | * This will not be a clean reboot, with everything | |
330 | * shutting down. But if there is a chance of | |
331 | * rebooting the system it will be rebooted. | |
332 | */ | |
333 | if (panic_reboot_mode != REBOOT_UNDEFINED) | |
334 | reboot_mode = panic_reboot_mode; | |
335 | emergency_restart(); | |
336 | } | |
337 | #ifdef __sparc__ | |
338 | { | |
339 | extern int stop_a_enabled; | |
340 | /* Make sure the user can actually press Stop-A (L1-A) */ | |
341 | stop_a_enabled = 1; | |
342 | pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" | |
343 | "twice on console to return to the boot prom\n"); | |
344 | } | |
345 | #endif | |
346 | #if defined(CONFIG_S390) | |
347 | disabled_wait(); | |
348 | #endif | |
349 | pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); | |
350 | ||
351 | /* Do not scroll important messages printed above */ | |
352 | suppress_printk = 1; | |
353 | local_irq_enable(); | |
354 | for (i = 0; ; i += PANIC_TIMER_STEP) { | |
355 | touch_softlockup_watchdog(); | |
356 | if (i >= i_next) { | |
357 | i += panic_blink(state ^= 1); | |
358 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
359 | } | |
360 | mdelay(PANIC_TIMER_STEP); | |
361 | } | |
362 | } | |
363 | ||
364 | EXPORT_SYMBOL(panic); | |
365 | ||
366 | /* | |
367 | * TAINT_FORCED_RMMOD could be a per-module flag but the module | |
368 | * is being removed anyway. | |
369 | */ | |
370 | const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { | |
371 | [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true }, | |
372 | [ TAINT_FORCED_MODULE ] = { 'F', ' ', true }, | |
373 | [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false }, | |
374 | [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false }, | |
375 | [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false }, | |
376 | [ TAINT_BAD_PAGE ] = { 'B', ' ', false }, | |
377 | [ TAINT_USER ] = { 'U', ' ', false }, | |
378 | [ TAINT_DIE ] = { 'D', ' ', false }, | |
379 | [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false }, | |
380 | [ TAINT_WARN ] = { 'W', ' ', false }, | |
381 | [ TAINT_CRAP ] = { 'C', ' ', true }, | |
382 | [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, | |
383 | [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, | |
384 | [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, | |
385 | [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, | |
386 | [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, | |
387 | [ TAINT_AUX ] = { 'X', ' ', true }, | |
388 | [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, | |
389 | }; | |
390 | ||
391 | /** | |
392 | * print_tainted - return a string to represent the kernel taint state. | |
393 | * | |
394 | * For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst | |
395 | * | |
396 | * The string is overwritten by the next call to print_tainted(), | |
397 | * but is always NULL terminated. | |
398 | */ | |
399 | const char *print_tainted(void) | |
400 | { | |
401 | static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")]; | |
402 | ||
403 | BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT); | |
404 | ||
405 | if (tainted_mask) { | |
406 | char *s; | |
407 | int i; | |
408 | ||
409 | s = buf + sprintf(buf, "Tainted: "); | |
410 | for (i = 0; i < TAINT_FLAGS_COUNT; i++) { | |
411 | const struct taint_flag *t = &taint_flags[i]; | |
412 | *s++ = test_bit(i, &tainted_mask) ? | |
413 | t->c_true : t->c_false; | |
414 | } | |
415 | *s = 0; | |
416 | } else | |
417 | snprintf(buf, sizeof(buf), "Not tainted"); | |
418 | ||
419 | return buf; | |
420 | } | |
421 | ||
422 | int test_taint(unsigned flag) | |
423 | { | |
424 | return test_bit(flag, &tainted_mask); | |
425 | } | |
426 | EXPORT_SYMBOL(test_taint); | |
427 | ||
428 | unsigned long get_taint(void) | |
429 | { | |
430 | return tainted_mask; | |
431 | } | |
432 | ||
433 | /** | |
434 | * add_taint: add a taint flag if not already set. | |
435 | * @flag: one of the TAINT_* constants. | |
436 | * @lockdep_ok: whether lock debugging is still OK. | |
437 | * | |
438 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
439 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
440 | */ | |
441 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
442 | { | |
443 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) | |
444 | pr_warn("Disabling lock debugging due to kernel taint\n"); | |
445 | ||
446 | set_bit(flag, &tainted_mask); | |
447 | ||
448 | if (tainted_mask & panic_on_taint) { | |
449 | panic_on_taint = 0; | |
450 | panic("panic_on_taint set ..."); | |
451 | } | |
452 | } | |
453 | EXPORT_SYMBOL(add_taint); | |
454 | ||
455 | static void spin_msec(int msecs) | |
456 | { | |
457 | int i; | |
458 | ||
459 | for (i = 0; i < msecs; i++) { | |
460 | touch_nmi_watchdog(); | |
461 | mdelay(1); | |
462 | } | |
463 | } | |
464 | ||
465 | /* | |
466 | * It just happens that oops_enter() and oops_exit() are identically | |
467 | * implemented... | |
468 | */ | |
469 | static void do_oops_enter_exit(void) | |
470 | { | |
471 | unsigned long flags; | |
472 | static int spin_counter; | |
473 | ||
474 | if (!pause_on_oops) | |
475 | return; | |
476 | ||
477 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
478 | if (pause_on_oops_flag == 0) { | |
479 | /* This CPU may now print the oops message */ | |
480 | pause_on_oops_flag = 1; | |
481 | } else { | |
482 | /* We need to stall this CPU */ | |
483 | if (!spin_counter) { | |
484 | /* This CPU gets to do the counting */ | |
485 | spin_counter = pause_on_oops; | |
486 | do { | |
487 | spin_unlock(&pause_on_oops_lock); | |
488 | spin_msec(MSEC_PER_SEC); | |
489 | spin_lock(&pause_on_oops_lock); | |
490 | } while (--spin_counter); | |
491 | pause_on_oops_flag = 0; | |
492 | } else { | |
493 | /* This CPU waits for a different one */ | |
494 | while (spin_counter) { | |
495 | spin_unlock(&pause_on_oops_lock); | |
496 | spin_msec(1); | |
497 | spin_lock(&pause_on_oops_lock); | |
498 | } | |
499 | } | |
500 | } | |
501 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
502 | } | |
503 | ||
504 | /* | |
505 | * Return true if the calling CPU is allowed to print oops-related info. | |
506 | * This is a bit racy.. | |
507 | */ | |
508 | bool oops_may_print(void) | |
509 | { | |
510 | return pause_on_oops_flag == 0; | |
511 | } | |
512 | ||
513 | /* | |
514 | * Called when the architecture enters its oops handler, before it prints | |
515 | * anything. If this is the first CPU to oops, and it's oopsing the first | |
516 | * time then let it proceed. | |
517 | * | |
518 | * This is all enabled by the pause_on_oops kernel boot option. We do all | |
519 | * this to ensure that oopses don't scroll off the screen. It has the | |
520 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
521 | * too. | |
522 | * | |
523 | * It turns out that the CPU which is allowed to print ends up pausing for | |
524 | * the right duration, whereas all the other CPUs pause for twice as long: | |
525 | * once in oops_enter(), once in oops_exit(). | |
526 | */ | |
527 | void oops_enter(void) | |
528 | { | |
529 | tracing_off(); | |
530 | /* can't trust the integrity of the kernel anymore: */ | |
531 | debug_locks_off(); | |
532 | do_oops_enter_exit(); | |
533 | ||
534 | if (sysctl_oops_all_cpu_backtrace) | |
535 | trigger_all_cpu_backtrace(); | |
536 | } | |
537 | ||
538 | /* | |
539 | * 64-bit random ID for oopses: | |
540 | */ | |
541 | static u64 oops_id; | |
542 | ||
543 | static int init_oops_id(void) | |
544 | { | |
545 | if (!oops_id) | |
546 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
547 | else | |
548 | oops_id++; | |
549 | ||
550 | return 0; | |
551 | } | |
552 | late_initcall(init_oops_id); | |
553 | ||
554 | static void print_oops_end_marker(void) | |
555 | { | |
556 | init_oops_id(); | |
557 | pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id); | |
558 | } | |
559 | ||
560 | /* | |
561 | * Called when the architecture exits its oops handler, after printing | |
562 | * everything. | |
563 | */ | |
564 | void oops_exit(void) | |
565 | { | |
566 | do_oops_enter_exit(); | |
567 | print_oops_end_marker(); | |
568 | kmsg_dump(KMSG_DUMP_OOPS); | |
569 | } | |
570 | ||
571 | struct warn_args { | |
572 | const char *fmt; | |
573 | va_list args; | |
574 | }; | |
575 | ||
576 | void __warn(const char *file, int line, void *caller, unsigned taint, | |
577 | struct pt_regs *regs, struct warn_args *args) | |
578 | { | |
579 | disable_trace_on_warning(); | |
580 | ||
581 | if (file) | |
582 | pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", | |
583 | raw_smp_processor_id(), current->pid, file, line, | |
584 | caller); | |
585 | else | |
586 | pr_warn("WARNING: CPU: %d PID: %d at %pS\n", | |
587 | raw_smp_processor_id(), current->pid, caller); | |
588 | ||
589 | if (args) | |
590 | vprintk(args->fmt, args->args); | |
591 | ||
592 | print_modules(); | |
593 | ||
594 | if (regs) | |
595 | show_regs(regs); | |
596 | ||
597 | if (panic_on_warn) { | |
598 | /* | |
599 | * This thread may hit another WARN() in the panic path. | |
600 | * Resetting this prevents additional WARN() from panicking the | |
601 | * system on this thread. Other threads are blocked by the | |
602 | * panic_mutex in panic(). | |
603 | */ | |
604 | panic_on_warn = 0; | |
605 | panic("panic_on_warn set ...\n"); | |
606 | } | |
607 | ||
608 | if (!regs) | |
609 | dump_stack(); | |
610 | ||
611 | print_irqtrace_events(current); | |
612 | ||
613 | print_oops_end_marker(); | |
614 | ||
615 | /* Just a warning, don't kill lockdep. */ | |
616 | add_taint(taint, LOCKDEP_STILL_OK); | |
617 | } | |
618 | ||
619 | #ifndef __WARN_FLAGS | |
620 | void warn_slowpath_fmt(const char *file, int line, unsigned taint, | |
621 | const char *fmt, ...) | |
622 | { | |
623 | struct warn_args args; | |
624 | ||
625 | pr_warn(CUT_HERE); | |
626 | ||
627 | if (!fmt) { | |
628 | __warn(file, line, __builtin_return_address(0), taint, | |
629 | NULL, NULL); | |
630 | return; | |
631 | } | |
632 | ||
633 | args.fmt = fmt; | |
634 | va_start(args.args, fmt); | |
635 | __warn(file, line, __builtin_return_address(0), taint, NULL, &args); | |
636 | va_end(args.args); | |
637 | } | |
638 | EXPORT_SYMBOL(warn_slowpath_fmt); | |
639 | #else | |
640 | void __warn_printk(const char *fmt, ...) | |
641 | { | |
642 | va_list args; | |
643 | ||
644 | pr_warn(CUT_HERE); | |
645 | ||
646 | va_start(args, fmt); | |
647 | vprintk(fmt, args); | |
648 | va_end(args); | |
649 | } | |
650 | EXPORT_SYMBOL(__warn_printk); | |
651 | #endif | |
652 | ||
653 | #ifdef CONFIG_BUG | |
654 | ||
655 | /* Support resetting WARN*_ONCE state */ | |
656 | ||
657 | static int clear_warn_once_set(void *data, u64 val) | |
658 | { | |
659 | generic_bug_clear_once(); | |
660 | memset(__start_once, 0, __end_once - __start_once); | |
661 | return 0; | |
662 | } | |
663 | ||
664 | DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, | |
665 | "%lld\n"); | |
666 | ||
667 | static __init int register_warn_debugfs(void) | |
668 | { | |
669 | /* Don't care about failure */ | |
670 | debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, | |
671 | &clear_warn_once_fops); | |
672 | return 0; | |
673 | } | |
674 | ||
675 | device_initcall(register_warn_debugfs); | |
676 | #endif | |
677 | ||
678 | #ifdef CONFIG_STACKPROTECTOR | |
679 | ||
680 | /* | |
681 | * Called when gcc's -fstack-protector feature is used, and | |
682 | * gcc detects corruption of the on-stack canary value | |
683 | */ | |
684 | __visible noinstr void __stack_chk_fail(void) | |
685 | { | |
686 | instrumentation_begin(); | |
687 | panic("stack-protector: Kernel stack is corrupted in: %pB", | |
688 | __builtin_return_address(0)); | |
689 | instrumentation_end(); | |
690 | } | |
691 | EXPORT_SYMBOL(__stack_chk_fail); | |
692 | ||
693 | #endif | |
694 | ||
695 | core_param(panic, panic_timeout, int, 0644); | |
696 | core_param(panic_print, panic_print, ulong, 0644); | |
697 | core_param(pause_on_oops, pause_on_oops, int, 0644); | |
698 | core_param(panic_on_warn, panic_on_warn, int, 0644); | |
699 | core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644); | |
700 | ||
701 | static int __init oops_setup(char *s) | |
702 | { | |
703 | if (!s) | |
704 | return -EINVAL; | |
705 | if (!strcmp(s, "panic")) | |
706 | panic_on_oops = 1; | |
707 | return 0; | |
708 | } | |
709 | early_param("oops", oops_setup); | |
710 | ||
711 | static int __init panic_on_taint_setup(char *s) | |
712 | { | |
713 | char *taint_str; | |
714 | ||
715 | if (!s) | |
716 | return -EINVAL; | |
717 | ||
718 | taint_str = strsep(&s, ","); | |
719 | if (kstrtoul(taint_str, 16, &panic_on_taint)) | |
720 | return -EINVAL; | |
721 | ||
722 | /* make sure panic_on_taint doesn't hold out-of-range TAINT flags */ | |
723 | panic_on_taint &= TAINT_FLAGS_MAX; | |
724 | ||
725 | if (!panic_on_taint) | |
726 | return -EINVAL; | |
727 | ||
728 | if (s && !strcmp(s, "nousertaint")) | |
729 | panic_on_taint_nousertaint = true; | |
730 | ||
731 | pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%sabled\n", | |
732 | panic_on_taint, panic_on_taint_nousertaint ? "en" : "dis"); | |
733 | ||
734 | return 0; | |
735 | } | |
736 | early_param("panic_on_taint", panic_on_taint_setup); |