Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/panic.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * This function is used through-out the kernel (including mm and fs) | |
9 | * to indicate a major problem. | |
10 | */ | |
c95dbf27 IM |
11 | #include <linux/debug_locks.h> |
12 | #include <linux/interrupt.h> | |
456b565c | 13 | #include <linux/kmsg_dump.h> |
c95dbf27 IM |
14 | #include <linux/kallsyms.h> |
15 | #include <linux/notifier.h> | |
1da177e4 | 16 | #include <linux/module.h> |
c95dbf27 | 17 | #include <linux/random.h> |
1da177e4 | 18 | #include <linux/reboot.h> |
c95dbf27 IM |
19 | #include <linux/delay.h> |
20 | #include <linux/kexec.h> | |
21 | #include <linux/sched.h> | |
1da177e4 | 22 | #include <linux/sysrq.h> |
c95dbf27 | 23 | #include <linux/init.h> |
1da177e4 LT |
24 | #include <linux/nmi.h> |
25 | ||
c7ff0d9c TS |
26 | #define PANIC_TIMER_STEP 100 |
27 | #define PANIC_BLINK_SPD 18 | |
28 | ||
6fa3eb70 S |
29 | /* Machine specific panic information string */ |
30 | char *mach_panic_string; | |
31 | ||
2a01bb38 | 32 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
25ddbb18 | 33 | static unsigned long tainted_mask; |
dd287796 AM |
34 | static int pause_on_oops; |
35 | static int pause_on_oops_flag; | |
36 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
1da177e4 | 37 | |
6fa3eb70 S |
38 | #ifndef CONFIG_PANIC_TIMEOUT |
39 | #define CONFIG_PANIC_TIMEOUT 0 | |
40 | #endif | |
41 | int panic_timeout = CONFIG_PANIC_TIMEOUT; | |
81e88fdc | 42 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 43 | |
e041c683 | 44 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
45 | |
46 | EXPORT_SYMBOL(panic_notifier_list); | |
47 | ||
c7ff0d9c | 48 | static long no_blink(int state) |
8aeee85a | 49 | { |
c7ff0d9c | 50 | return 0; |
8aeee85a AB |
51 | } |
52 | ||
c7ff0d9c TS |
53 | /* Returns how long it waited in ms */ |
54 | long (*panic_blink)(int state); | |
55 | EXPORT_SYMBOL(panic_blink); | |
56 | ||
93e13a36 MH |
57 | /* |
58 | * Stop ourself in panic -- architecture code may override this | |
59 | */ | |
60 | void __weak panic_smp_self_stop(void) | |
61 | { | |
62 | while (1) | |
63 | cpu_relax(); | |
64 | } | |
65 | ||
1da177e4 LT |
66 | /** |
67 | * panic - halt the system | |
68 | * @fmt: The text string to print | |
69 | * | |
70 | * Display a message, then perform cleanups. | |
71 | * | |
72 | * This function never returns. | |
73 | */ | |
9402c95f | 74 | void panic(const char *fmt, ...) |
1da177e4 | 75 | { |
93e13a36 | 76 | static DEFINE_SPINLOCK(panic_lock); |
1da177e4 LT |
77 | static char buf[1024]; |
78 | va_list args; | |
c7ff0d9c TS |
79 | long i, i_next = 0; |
80 | int state = 0; | |
1da177e4 | 81 | |
190320c3 VM |
82 | /* |
83 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
84 | * from deadlocking the first cpu that invokes the panic, since | |
85 | * there is nothing to prevent an interrupt handler (that runs | |
86 | * after the panic_lock is acquired) from invoking panic again. | |
87 | */ | |
88 | local_irq_disable(); | |
89 | ||
dc009d92 | 90 | /* |
c95dbf27 IM |
91 | * It's possible to come here directly from a panic-assertion and |
92 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 93 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
94 | * |
95 | * Only one CPU is allowed to execute the panic code from here. For | |
96 | * multiple parallel invocations of panic, all other CPUs either | |
97 | * stop themself or will wait until they are stopped by the 1st CPU | |
98 | * with smp_send_stop(). | |
dc009d92 | 99 | */ |
93e13a36 MH |
100 | if (!spin_trylock(&panic_lock)) |
101 | panic_smp_self_stop(); | |
dc009d92 | 102 | |
5b530fc1 | 103 | console_verbose(); |
1da177e4 LT |
104 | bust_spinlocks(1); |
105 | va_start(args, fmt); | |
106 | vsnprintf(buf, sizeof(buf), fmt, args); | |
107 | va_end(args); | |
108 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
5cb27301 | 109 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
110 | /* |
111 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
112 | */ | |
026ee1f6 | 113 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 114 | dump_stack(); |
5cb27301 | 115 | #endif |
1da177e4 | 116 | |
dc009d92 EB |
117 | /* |
118 | * If we have crashed and we have a crash kernel loaded let it handle | |
119 | * everything else. | |
120 | * Do we want to call this before we try to display a message? | |
121 | */ | |
6e274d14 | 122 | crash_kexec(NULL); |
dc009d92 | 123 | |
dc009d92 EB |
124 | /* |
125 | * Note smp_send_stop is the usual smp shutdown function, which | |
126 | * unfortunately means it may not be hardened to work in a panic | |
127 | * situation. | |
128 | */ | |
1da177e4 | 129 | smp_send_stop(); |
1da177e4 | 130 | |
62be73ea SA |
131 | kmsg_dump(KMSG_DUMP_PANIC); |
132 | ||
e041c683 | 133 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 134 | |
d014e889 AK |
135 | bust_spinlocks(0); |
136 | ||
c7ff0d9c TS |
137 | if (!panic_blink) |
138 | panic_blink = no_blink; | |
139 | ||
dc009d92 | 140 | if (panic_timeout > 0) { |
1da177e4 | 141 | /* |
c95dbf27 IM |
142 | * Delay timeout seconds before rebooting the machine. |
143 | * We can't use the "normal" timers since we just panicked. | |
144 | */ | |
145 | printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout); | |
146 | ||
c7ff0d9c | 147 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 148 | touch_nmi_watchdog(); |
c7ff0d9c TS |
149 | if (i >= i_next) { |
150 | i += panic_blink(state ^= 1); | |
151 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
152 | } | |
153 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 154 | } |
4302fbc8 HD |
155 | } |
156 | if (panic_timeout != 0) { | |
c95dbf27 IM |
157 | /* |
158 | * This will not be a clean reboot, with everything | |
159 | * shutting down. But if there is a chance of | |
160 | * rebooting the system it will be rebooted. | |
1da177e4 | 161 | */ |
2f048ea8 | 162 | emergency_restart(); |
1da177e4 LT |
163 | } |
164 | #ifdef __sparc__ | |
165 | { | |
166 | extern int stop_a_enabled; | |
a271c241 | 167 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 168 | stop_a_enabled = 1; |
a271c241 | 169 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
170 | } |
171 | #endif | |
347a8dc3 | 172 | #if defined(CONFIG_S390) |
c95dbf27 IM |
173 | { |
174 | unsigned long caller; | |
175 | ||
176 | caller = (unsigned long)__builtin_return_address(0); | |
177 | disabled_wait(caller); | |
178 | } | |
1da177e4 LT |
179 | #endif |
180 | local_irq_enable(); | |
c7ff0d9c | 181 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 182 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
183 | if (i >= i_next) { |
184 | i += panic_blink(state ^= 1); | |
185 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
186 | } | |
187 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
188 | } |
189 | } | |
190 | ||
191 | EXPORT_SYMBOL(panic); | |
192 | ||
c277e63f | 193 | |
25ddbb18 | 194 | struct tnt { |
c95dbf27 IM |
195 | u8 bit; |
196 | char true; | |
197 | char false; | |
25ddbb18 AK |
198 | }; |
199 | ||
200 | static const struct tnt tnts[] = { | |
c95dbf27 IM |
201 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, |
202 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
203 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
204 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
205 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
206 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
207 | { TAINT_USER, 'U', ' ' }, | |
208 | { TAINT_DIE, 'D', ' ' }, | |
209 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
210 | { TAINT_WARN, 'W', ' ' }, | |
211 | { TAINT_CRAP, 'C', ' ' }, | |
92946bc7 | 212 | { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' }, |
2449b8ba | 213 | { TAINT_OOT_MODULE, 'O', ' ' }, |
25ddbb18 AK |
214 | }; |
215 | ||
1da177e4 LT |
216 | /** |
217 | * print_tainted - return a string to represent the kernel taint state. | |
218 | * | |
219 | * 'P' - Proprietary module has been loaded. | |
220 | * 'F' - Module has been forcibly loaded. | |
221 | * 'S' - SMP with CPUs not designed for SMP. | |
222 | * 'R' - User forced a module unload. | |
9aa5e993 | 223 | * 'M' - System experienced a machine check exception. |
1da177e4 | 224 | * 'B' - System has hit bad_page. |
34f5a398 | 225 | * 'U' - Userspace-defined naughtiness. |
a8005992 | 226 | * 'D' - Kernel has oopsed before |
95b570c9 NH |
227 | * 'A' - ACPI table overridden. |
228 | * 'W' - Taint on warning. | |
061b1bd3 | 229 | * 'C' - modules from drivers/staging are loaded. |
92946bc7 | 230 | * 'I' - Working around severe firmware bug. |
2449b8ba | 231 | * 'O' - Out-of-tree module has been loaded. |
1da177e4 | 232 | * |
fe002a41 | 233 | * The string is overwritten by the next call to print_tainted(). |
1da177e4 | 234 | */ |
1da177e4 LT |
235 | const char *print_tainted(void) |
236 | { | |
25ddbb18 AK |
237 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
238 | ||
239 | if (tainted_mask) { | |
240 | char *s; | |
241 | int i; | |
242 | ||
243 | s = buf + sprintf(buf, "Tainted: "); | |
244 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
245 | const struct tnt *t = &tnts[i]; | |
246 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
247 | t->true : t->false; | |
248 | } | |
249 | *s = 0; | |
250 | } else | |
1da177e4 | 251 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
252 | |
253 | return buf; | |
1da177e4 LT |
254 | } |
255 | ||
25ddbb18 | 256 | int test_taint(unsigned flag) |
1da177e4 | 257 | { |
25ddbb18 AK |
258 | return test_bit(flag, &tainted_mask); |
259 | } | |
260 | EXPORT_SYMBOL(test_taint); | |
261 | ||
262 | unsigned long get_taint(void) | |
263 | { | |
264 | return tainted_mask; | |
1da177e4 | 265 | } |
dd287796 | 266 | |
373d4d09 RR |
267 | /** |
268 | * add_taint: add a taint flag if not already set. | |
269 | * @flag: one of the TAINT_* constants. | |
270 | * @lockdep_ok: whether lock debugging is still OK. | |
271 | * | |
272 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
273 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
274 | */ | |
275 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 276 | { |
373d4d09 RR |
277 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
278 | printk(KERN_WARNING | |
279 | "Disabling lock debugging due to kernel taint\n"); | |
9eeba613 | 280 | |
25ddbb18 | 281 | set_bit(flag, &tainted_mask); |
dd287796 | 282 | } |
1da177e4 | 283 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
284 | |
285 | static void spin_msec(int msecs) | |
286 | { | |
287 | int i; | |
288 | ||
289 | for (i = 0; i < msecs; i++) { | |
290 | touch_nmi_watchdog(); | |
291 | mdelay(1); | |
292 | } | |
293 | } | |
294 | ||
295 | /* | |
296 | * It just happens that oops_enter() and oops_exit() are identically | |
297 | * implemented... | |
298 | */ | |
299 | static void do_oops_enter_exit(void) | |
300 | { | |
301 | unsigned long flags; | |
302 | static int spin_counter; | |
303 | ||
304 | if (!pause_on_oops) | |
305 | return; | |
306 | ||
307 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
308 | if (pause_on_oops_flag == 0) { | |
309 | /* This CPU may now print the oops message */ | |
310 | pause_on_oops_flag = 1; | |
311 | } else { | |
312 | /* We need to stall this CPU */ | |
313 | if (!spin_counter) { | |
314 | /* This CPU gets to do the counting */ | |
315 | spin_counter = pause_on_oops; | |
316 | do { | |
317 | spin_unlock(&pause_on_oops_lock); | |
318 | spin_msec(MSEC_PER_SEC); | |
319 | spin_lock(&pause_on_oops_lock); | |
320 | } while (--spin_counter); | |
321 | pause_on_oops_flag = 0; | |
322 | } else { | |
323 | /* This CPU waits for a different one */ | |
324 | while (spin_counter) { | |
325 | spin_unlock(&pause_on_oops_lock); | |
326 | spin_msec(1); | |
327 | spin_lock(&pause_on_oops_lock); | |
328 | } | |
329 | } | |
330 | } | |
331 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
332 | } | |
333 | ||
334 | /* | |
c95dbf27 IM |
335 | * Return true if the calling CPU is allowed to print oops-related info. |
336 | * This is a bit racy.. | |
dd287796 AM |
337 | */ |
338 | int oops_may_print(void) | |
339 | { | |
340 | return pause_on_oops_flag == 0; | |
341 | } | |
342 | ||
343 | /* | |
344 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
345 | * anything. If this is the first CPU to oops, and it's oopsing the first |
346 | * time then let it proceed. | |
dd287796 | 347 | * |
c95dbf27 IM |
348 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
349 | * this to ensure that oopses don't scroll off the screen. It has the | |
350 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
351 | * too. | |
dd287796 | 352 | * |
c95dbf27 IM |
353 | * It turns out that the CPU which is allowed to print ends up pausing for |
354 | * the right duration, whereas all the other CPUs pause for twice as long: | |
355 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
356 | */ |
357 | void oops_enter(void) | |
358 | { | |
bdff7870 | 359 | tracing_off(); |
c95dbf27 IM |
360 | /* can't trust the integrity of the kernel anymore: */ |
361 | debug_locks_off(); | |
dd287796 AM |
362 | do_oops_enter_exit(); |
363 | } | |
364 | ||
2c3b20e9 AV |
365 | /* |
366 | * 64-bit random ID for oopses: | |
367 | */ | |
368 | static u64 oops_id; | |
369 | ||
370 | static int init_oops_id(void) | |
371 | { | |
372 | if (!oops_id) | |
373 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
374 | else |
375 | oops_id++; | |
2c3b20e9 AV |
376 | |
377 | return 0; | |
378 | } | |
379 | late_initcall(init_oops_id); | |
380 | ||
863a6049 | 381 | void print_oops_end_marker(void) |
71c33911 AV |
382 | { |
383 | init_oops_id(); | |
6fa3eb70 S |
384 | |
385 | if (mach_panic_string) | |
386 | printk(KERN_WARNING "Board Information: %s\n", | |
387 | mach_panic_string); | |
388 | ||
71c33911 AV |
389 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", |
390 | (unsigned long long)oops_id); | |
391 | } | |
392 | ||
dd287796 AM |
393 | /* |
394 | * Called when the architecture exits its oops handler, after printing | |
395 | * everything. | |
396 | */ | |
397 | void oops_exit(void) | |
398 | { | |
399 | do_oops_enter_exit(); | |
71c33911 | 400 | print_oops_end_marker(); |
456b565c | 401 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 402 | } |
3162f751 | 403 | |
79b4cc5e | 404 | #ifdef WANT_WARN_ON_SLOWPATH |
0f6f49a8 LT |
405 | struct slowpath_args { |
406 | const char *fmt; | |
a8f18b90 | 407 | va_list args; |
0f6f49a8 | 408 | }; |
bd89bb29 | 409 | |
b2be0527 BH |
410 | static void warn_slowpath_common(const char *file, int line, void *caller, |
411 | unsigned taint, struct slowpath_args *args) | |
0f6f49a8 | 412 | { |
a8f18b90 | 413 | printk(KERN_WARNING "------------[ cut here ]------------\n"); |
0f6f49a8 | 414 | printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller); |
74853dba | 415 | |
0f6f49a8 LT |
416 | if (args) |
417 | vprintk(args->fmt, args->args); | |
a8f18b90 AV |
418 | |
419 | print_modules(); | |
420 | dump_stack(); | |
421 | print_oops_end_marker(); | |
373d4d09 RR |
422 | /* Just a warning, don't kill lockdep. */ |
423 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 424 | } |
0f6f49a8 LT |
425 | |
426 | void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) | |
427 | { | |
428 | struct slowpath_args args; | |
429 | ||
430 | args.fmt = fmt; | |
431 | va_start(args.args, fmt); | |
b2be0527 BH |
432 | warn_slowpath_common(file, line, __builtin_return_address(0), |
433 | TAINT_WARN, &args); | |
0f6f49a8 LT |
434 | va_end(args.args); |
435 | } | |
57adc4d2 AK |
436 | EXPORT_SYMBOL(warn_slowpath_fmt); |
437 | ||
b2be0527 BH |
438 | void warn_slowpath_fmt_taint(const char *file, int line, |
439 | unsigned taint, const char *fmt, ...) | |
440 | { | |
441 | struct slowpath_args args; | |
442 | ||
443 | args.fmt = fmt; | |
444 | va_start(args.args, fmt); | |
445 | warn_slowpath_common(file, line, __builtin_return_address(0), | |
446 | taint, &args); | |
447 | va_end(args.args); | |
448 | } | |
449 | EXPORT_SYMBOL(warn_slowpath_fmt_taint); | |
450 | ||
57adc4d2 AK |
451 | void warn_slowpath_null(const char *file, int line) |
452 | { | |
b2be0527 BH |
453 | warn_slowpath_common(file, line, __builtin_return_address(0), |
454 | TAINT_WARN, NULL); | |
57adc4d2 AK |
455 | } |
456 | EXPORT_SYMBOL(warn_slowpath_null); | |
79b4cc5e AV |
457 | #endif |
458 | ||
3162f751 | 459 | #ifdef CONFIG_CC_STACKPROTECTOR |
54371a43 | 460 | |
3162f751 AV |
461 | /* |
462 | * Called when gcc's -fstack-protector feature is used, and | |
463 | * gcc detects corruption of the on-stack canary value | |
464 | */ | |
465 | void __stack_chk_fail(void) | |
466 | { | |
6fa3eb70 | 467 | /* |
517a92c4 IM |
468 | panic("stack-protector: Kernel stack is corrupted in: %p\n", |
469 | __builtin_return_address(0)); | |
6fa3eb70 S |
470 | */ |
471 | BUG(); | |
472 | printk(KERN_ERR "stack-protector: Kernel stack is corrupted in: %p\n", | |
473 | __builtin_return_address(0)); | |
3162f751 AV |
474 | } |
475 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 476 | |
3162f751 | 477 | #endif |
f44dd164 RR |
478 | |
479 | core_param(panic, panic_timeout, int, 0644); | |
480 | core_param(pause_on_oops, pause_on_oops, int, 0644); | |
d404ab0a OH |
481 | |
482 | static int __init oops_setup(char *s) | |
483 | { | |
484 | if (!s) | |
485 | return -EINVAL; | |
486 | if (!strcmp(s, "panic")) | |
487 | panic_on_oops = 1; | |
488 | return 0; | |
489 | } | |
490 | early_param("oops", oops_setup); |