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 | 24 | #include <linux/nmi.h> |
0ba4f4bb | 25 | #include <linux/console.h> |
1da177e4 | 26 | |
c7ff0d9c TS |
27 | #define PANIC_TIMER_STEP 100 |
28 | #define PANIC_BLINK_SPD 18 | |
29 | ||
6fa3eb70 S |
30 | /* Machine specific panic information string */ |
31 | char *mach_panic_string; | |
32 | ||
2a01bb38 | 33 | int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE; |
25ddbb18 | 34 | static unsigned long tainted_mask; |
dd287796 AM |
35 | static int pause_on_oops; |
36 | static int pause_on_oops_flag; | |
37 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
1da177e4 | 38 | |
6fa3eb70 S |
39 | #ifndef CONFIG_PANIC_TIMEOUT |
40 | #define CONFIG_PANIC_TIMEOUT 0 | |
41 | #endif | |
42 | int panic_timeout = CONFIG_PANIC_TIMEOUT; | |
81e88fdc | 43 | EXPORT_SYMBOL_GPL(panic_timeout); |
1da177e4 | 44 | |
e041c683 | 45 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
46 | |
47 | EXPORT_SYMBOL(panic_notifier_list); | |
48 | ||
c7ff0d9c | 49 | static long no_blink(int state) |
8aeee85a | 50 | { |
c7ff0d9c | 51 | return 0; |
8aeee85a AB |
52 | } |
53 | ||
c7ff0d9c TS |
54 | /* Returns how long it waited in ms */ |
55 | long (*panic_blink)(int state); | |
56 | EXPORT_SYMBOL(panic_blink); | |
57 | ||
93e13a36 MH |
58 | /* |
59 | * Stop ourself in panic -- architecture code may override this | |
60 | */ | |
61 | void __weak panic_smp_self_stop(void) | |
62 | { | |
63 | while (1) | |
64 | cpu_relax(); | |
65 | } | |
66 | ||
1da177e4 LT |
67 | /** |
68 | * panic - halt the system | |
69 | * @fmt: The text string to print | |
70 | * | |
71 | * Display a message, then perform cleanups. | |
72 | * | |
73 | * This function never returns. | |
74 | */ | |
9402c95f | 75 | void panic(const char *fmt, ...) |
1da177e4 | 76 | { |
93e13a36 | 77 | static DEFINE_SPINLOCK(panic_lock); |
1da177e4 LT |
78 | static char buf[1024]; |
79 | va_list args; | |
c7ff0d9c TS |
80 | long i, i_next = 0; |
81 | int state = 0; | |
1da177e4 | 82 | |
190320c3 VM |
83 | /* |
84 | * Disable local interrupts. This will prevent panic_smp_self_stop | |
85 | * from deadlocking the first cpu that invokes the panic, since | |
86 | * there is nothing to prevent an interrupt handler (that runs | |
87 | * after the panic_lock is acquired) from invoking panic again. | |
88 | */ | |
89 | local_irq_disable(); | |
90 | ||
dc009d92 | 91 | /* |
c95dbf27 IM |
92 | * It's possible to come here directly from a panic-assertion and |
93 | * not have preempt disabled. Some functions called from here want | |
dc009d92 | 94 | * preempt to be disabled. No point enabling it later though... |
93e13a36 MH |
95 | * |
96 | * Only one CPU is allowed to execute the panic code from here. For | |
97 | * multiple parallel invocations of panic, all other CPUs either | |
98 | * stop themself or will wait until they are stopped by the 1st CPU | |
99 | * with smp_send_stop(). | |
dc009d92 | 100 | */ |
93e13a36 MH |
101 | if (!spin_trylock(&panic_lock)) |
102 | panic_smp_self_stop(); | |
dc009d92 | 103 | |
5b530fc1 | 104 | console_verbose(); |
1da177e4 LT |
105 | bust_spinlocks(1); |
106 | va_start(args, fmt); | |
107 | vsnprintf(buf, sizeof(buf), fmt, args); | |
108 | va_end(args); | |
109 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
5cb27301 | 110 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
6e6f0a1f AK |
111 | /* |
112 | * Avoid nested stack-dumping if a panic occurs during oops processing | |
113 | */ | |
026ee1f6 | 114 | if (!test_taint(TAINT_DIE) && oops_in_progress <= 1) |
6e6f0a1f | 115 | dump_stack(); |
5cb27301 | 116 | #endif |
1da177e4 | 117 | |
dc009d92 EB |
118 | /* |
119 | * If we have crashed and we have a crash kernel loaded let it handle | |
120 | * everything else. | |
121 | * Do we want to call this before we try to display a message? | |
122 | */ | |
6e274d14 | 123 | crash_kexec(NULL); |
dc009d92 | 124 | |
dc009d92 EB |
125 | /* |
126 | * Note smp_send_stop is the usual smp shutdown function, which | |
127 | * unfortunately means it may not be hardened to work in a panic | |
128 | * situation. | |
129 | */ | |
1da177e4 | 130 | smp_send_stop(); |
1da177e4 | 131 | |
62be73ea SA |
132 | kmsg_dump(KMSG_DUMP_PANIC); |
133 | ||
e041c683 | 134 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 135 | |
d014e889 AK |
136 | bust_spinlocks(0); |
137 | ||
0ba4f4bb TH |
138 | console_flush_on_panic(); |
139 | ||
c7ff0d9c TS |
140 | if (!panic_blink) |
141 | panic_blink = no_blink; | |
142 | ||
dc009d92 | 143 | if (panic_timeout > 0) { |
1da177e4 | 144 | /* |
c95dbf27 IM |
145 | * Delay timeout seconds before rebooting the machine. |
146 | * We can't use the "normal" timers since we just panicked. | |
147 | */ | |
148 | printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout); | |
149 | ||
c7ff0d9c | 150 | for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) { |
1da177e4 | 151 | touch_nmi_watchdog(); |
c7ff0d9c TS |
152 | if (i >= i_next) { |
153 | i += panic_blink(state ^= 1); | |
154 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
155 | } | |
156 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 | 157 | } |
4302fbc8 HD |
158 | } |
159 | if (panic_timeout != 0) { | |
c95dbf27 IM |
160 | /* |
161 | * This will not be a clean reboot, with everything | |
162 | * shutting down. But if there is a chance of | |
163 | * rebooting the system it will be rebooted. | |
1da177e4 | 164 | */ |
2f048ea8 | 165 | emergency_restart(); |
1da177e4 LT |
166 | } |
167 | #ifdef __sparc__ | |
168 | { | |
169 | extern int stop_a_enabled; | |
a271c241 | 170 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 171 | stop_a_enabled = 1; |
a271c241 | 172 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
173 | } |
174 | #endif | |
347a8dc3 | 175 | #if defined(CONFIG_S390) |
c95dbf27 IM |
176 | { |
177 | unsigned long caller; | |
178 | ||
179 | caller = (unsigned long)__builtin_return_address(0); | |
180 | disabled_wait(caller); | |
181 | } | |
1da177e4 LT |
182 | #endif |
183 | local_irq_enable(); | |
c7ff0d9c | 184 | for (i = 0; ; i += PANIC_TIMER_STEP) { |
c22db941 | 185 | touch_softlockup_watchdog(); |
c7ff0d9c TS |
186 | if (i >= i_next) { |
187 | i += panic_blink(state ^= 1); | |
188 | i_next = i + 3600 / PANIC_BLINK_SPD; | |
189 | } | |
190 | mdelay(PANIC_TIMER_STEP); | |
1da177e4 LT |
191 | } |
192 | } | |
193 | ||
194 | EXPORT_SYMBOL(panic); | |
195 | ||
c277e63f | 196 | |
25ddbb18 | 197 | struct tnt { |
c95dbf27 IM |
198 | u8 bit; |
199 | char true; | |
200 | char false; | |
25ddbb18 AK |
201 | }; |
202 | ||
203 | static const struct tnt tnts[] = { | |
c95dbf27 IM |
204 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, |
205 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
206 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
207 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
208 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
209 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
210 | { TAINT_USER, 'U', ' ' }, | |
211 | { TAINT_DIE, 'D', ' ' }, | |
212 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
213 | { TAINT_WARN, 'W', ' ' }, | |
214 | { TAINT_CRAP, 'C', ' ' }, | |
92946bc7 | 215 | { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' }, |
2449b8ba | 216 | { TAINT_OOT_MODULE, 'O', ' ' }, |
25ddbb18 AK |
217 | }; |
218 | ||
1da177e4 LT |
219 | /** |
220 | * print_tainted - return a string to represent the kernel taint state. | |
221 | * | |
222 | * 'P' - Proprietary module has been loaded. | |
223 | * 'F' - Module has been forcibly loaded. | |
224 | * 'S' - SMP with CPUs not designed for SMP. | |
225 | * 'R' - User forced a module unload. | |
9aa5e993 | 226 | * 'M' - System experienced a machine check exception. |
1da177e4 | 227 | * 'B' - System has hit bad_page. |
34f5a398 | 228 | * 'U' - Userspace-defined naughtiness. |
a8005992 | 229 | * 'D' - Kernel has oopsed before |
95b570c9 NH |
230 | * 'A' - ACPI table overridden. |
231 | * 'W' - Taint on warning. | |
061b1bd3 | 232 | * 'C' - modules from drivers/staging are loaded. |
92946bc7 | 233 | * 'I' - Working around severe firmware bug. |
2449b8ba | 234 | * 'O' - Out-of-tree module has been loaded. |
1da177e4 | 235 | * |
fe002a41 | 236 | * The string is overwritten by the next call to print_tainted(). |
1da177e4 | 237 | */ |
1da177e4 LT |
238 | const char *print_tainted(void) |
239 | { | |
25ddbb18 AK |
240 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
241 | ||
242 | if (tainted_mask) { | |
243 | char *s; | |
244 | int i; | |
245 | ||
246 | s = buf + sprintf(buf, "Tainted: "); | |
247 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
248 | const struct tnt *t = &tnts[i]; | |
249 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
250 | t->true : t->false; | |
251 | } | |
252 | *s = 0; | |
253 | } else | |
1da177e4 | 254 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
255 | |
256 | return buf; | |
1da177e4 LT |
257 | } |
258 | ||
25ddbb18 | 259 | int test_taint(unsigned flag) |
1da177e4 | 260 | { |
25ddbb18 AK |
261 | return test_bit(flag, &tainted_mask); |
262 | } | |
263 | EXPORT_SYMBOL(test_taint); | |
264 | ||
265 | unsigned long get_taint(void) | |
266 | { | |
267 | return tainted_mask; | |
1da177e4 | 268 | } |
dd287796 | 269 | |
373d4d09 RR |
270 | /** |
271 | * add_taint: add a taint flag if not already set. | |
272 | * @flag: one of the TAINT_* constants. | |
273 | * @lockdep_ok: whether lock debugging is still OK. | |
274 | * | |
275 | * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for | |
276 | * some notewortht-but-not-corrupting cases, it can be set to true. | |
277 | */ | |
278 | void add_taint(unsigned flag, enum lockdep_ok lockdep_ok) | |
dd287796 | 279 | { |
373d4d09 RR |
280 | if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off()) |
281 | printk(KERN_WARNING | |
282 | "Disabling lock debugging due to kernel taint\n"); | |
9eeba613 | 283 | |
25ddbb18 | 284 | set_bit(flag, &tainted_mask); |
dd287796 | 285 | } |
1da177e4 | 286 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
287 | |
288 | static void spin_msec(int msecs) | |
289 | { | |
290 | int i; | |
291 | ||
292 | for (i = 0; i < msecs; i++) { | |
293 | touch_nmi_watchdog(); | |
294 | mdelay(1); | |
295 | } | |
296 | } | |
297 | ||
298 | /* | |
299 | * It just happens that oops_enter() and oops_exit() are identically | |
300 | * implemented... | |
301 | */ | |
302 | static void do_oops_enter_exit(void) | |
303 | { | |
304 | unsigned long flags; | |
305 | static int spin_counter; | |
306 | ||
307 | if (!pause_on_oops) | |
308 | return; | |
309 | ||
310 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
311 | if (pause_on_oops_flag == 0) { | |
312 | /* This CPU may now print the oops message */ | |
313 | pause_on_oops_flag = 1; | |
314 | } else { | |
315 | /* We need to stall this CPU */ | |
316 | if (!spin_counter) { | |
317 | /* This CPU gets to do the counting */ | |
318 | spin_counter = pause_on_oops; | |
319 | do { | |
320 | spin_unlock(&pause_on_oops_lock); | |
321 | spin_msec(MSEC_PER_SEC); | |
322 | spin_lock(&pause_on_oops_lock); | |
323 | } while (--spin_counter); | |
324 | pause_on_oops_flag = 0; | |
325 | } else { | |
326 | /* This CPU waits for a different one */ | |
327 | while (spin_counter) { | |
328 | spin_unlock(&pause_on_oops_lock); | |
329 | spin_msec(1); | |
330 | spin_lock(&pause_on_oops_lock); | |
331 | } | |
332 | } | |
333 | } | |
334 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
335 | } | |
336 | ||
337 | /* | |
c95dbf27 IM |
338 | * Return true if the calling CPU is allowed to print oops-related info. |
339 | * This is a bit racy.. | |
dd287796 AM |
340 | */ |
341 | int oops_may_print(void) | |
342 | { | |
343 | return pause_on_oops_flag == 0; | |
344 | } | |
345 | ||
346 | /* | |
347 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
348 | * anything. If this is the first CPU to oops, and it's oopsing the first |
349 | * time then let it proceed. | |
dd287796 | 350 | * |
c95dbf27 IM |
351 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
352 | * this to ensure that oopses don't scroll off the screen. It has the | |
353 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
354 | * too. | |
dd287796 | 355 | * |
c95dbf27 IM |
356 | * It turns out that the CPU which is allowed to print ends up pausing for |
357 | * the right duration, whereas all the other CPUs pause for twice as long: | |
358 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
359 | */ |
360 | void oops_enter(void) | |
361 | { | |
bdff7870 | 362 | tracing_off(); |
c95dbf27 IM |
363 | /* can't trust the integrity of the kernel anymore: */ |
364 | debug_locks_off(); | |
dd287796 AM |
365 | do_oops_enter_exit(); |
366 | } | |
367 | ||
2c3b20e9 AV |
368 | /* |
369 | * 64-bit random ID for oopses: | |
370 | */ | |
371 | static u64 oops_id; | |
372 | ||
373 | static int init_oops_id(void) | |
374 | { | |
375 | if (!oops_id) | |
376 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
377 | else |
378 | oops_id++; | |
2c3b20e9 AV |
379 | |
380 | return 0; | |
381 | } | |
382 | late_initcall(init_oops_id); | |
383 | ||
863a6049 | 384 | void print_oops_end_marker(void) |
71c33911 AV |
385 | { |
386 | init_oops_id(); | |
6fa3eb70 S |
387 | |
388 | if (mach_panic_string) | |
389 | printk(KERN_WARNING "Board Information: %s\n", | |
390 | mach_panic_string); | |
391 | ||
71c33911 AV |
392 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", |
393 | (unsigned long long)oops_id); | |
394 | } | |
395 | ||
dd287796 AM |
396 | /* |
397 | * Called when the architecture exits its oops handler, after printing | |
398 | * everything. | |
399 | */ | |
400 | void oops_exit(void) | |
401 | { | |
402 | do_oops_enter_exit(); | |
71c33911 | 403 | print_oops_end_marker(); |
456b565c | 404 | kmsg_dump(KMSG_DUMP_OOPS); |
dd287796 | 405 | } |
3162f751 | 406 | |
79b4cc5e | 407 | #ifdef WANT_WARN_ON_SLOWPATH |
0f6f49a8 LT |
408 | struct slowpath_args { |
409 | const char *fmt; | |
a8f18b90 | 410 | va_list args; |
0f6f49a8 | 411 | }; |
bd89bb29 | 412 | |
b2be0527 BH |
413 | static void warn_slowpath_common(const char *file, int line, void *caller, |
414 | unsigned taint, struct slowpath_args *args) | |
0f6f49a8 | 415 | { |
a8f18b90 | 416 | printk(KERN_WARNING "------------[ cut here ]------------\n"); |
0f6f49a8 | 417 | printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller); |
74853dba | 418 | |
0f6f49a8 LT |
419 | if (args) |
420 | vprintk(args->fmt, args->args); | |
a8f18b90 AV |
421 | |
422 | print_modules(); | |
423 | dump_stack(); | |
424 | print_oops_end_marker(); | |
373d4d09 RR |
425 | /* Just a warning, don't kill lockdep. */ |
426 | add_taint(taint, LOCKDEP_STILL_OK); | |
a8f18b90 | 427 | } |
0f6f49a8 LT |
428 | |
429 | void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) | |
430 | { | |
431 | struct slowpath_args args; | |
432 | ||
433 | args.fmt = fmt; | |
434 | va_start(args.args, fmt); | |
b2be0527 BH |
435 | warn_slowpath_common(file, line, __builtin_return_address(0), |
436 | TAINT_WARN, &args); | |
0f6f49a8 LT |
437 | va_end(args.args); |
438 | } | |
57adc4d2 AK |
439 | EXPORT_SYMBOL(warn_slowpath_fmt); |
440 | ||
b2be0527 BH |
441 | void warn_slowpath_fmt_taint(const char *file, int line, |
442 | unsigned taint, const char *fmt, ...) | |
443 | { | |
444 | struct slowpath_args args; | |
445 | ||
446 | args.fmt = fmt; | |
447 | va_start(args.args, fmt); | |
448 | warn_slowpath_common(file, line, __builtin_return_address(0), | |
449 | taint, &args); | |
450 | va_end(args.args); | |
451 | } | |
452 | EXPORT_SYMBOL(warn_slowpath_fmt_taint); | |
453 | ||
57adc4d2 AK |
454 | void warn_slowpath_null(const char *file, int line) |
455 | { | |
b2be0527 BH |
456 | warn_slowpath_common(file, line, __builtin_return_address(0), |
457 | TAINT_WARN, NULL); | |
57adc4d2 AK |
458 | } |
459 | EXPORT_SYMBOL(warn_slowpath_null); | |
79b4cc5e AV |
460 | #endif |
461 | ||
3162f751 | 462 | #ifdef CONFIG_CC_STACKPROTECTOR |
54371a43 | 463 | |
3162f751 AV |
464 | /* |
465 | * Called when gcc's -fstack-protector feature is used, and | |
466 | * gcc detects corruption of the on-stack canary value | |
467 | */ | |
468 | void __stack_chk_fail(void) | |
469 | { | |
6fa3eb70 | 470 | /* |
517a92c4 IM |
471 | panic("stack-protector: Kernel stack is corrupted in: %p\n", |
472 | __builtin_return_address(0)); | |
6fa3eb70 S |
473 | */ |
474 | BUG(); | |
475 | printk(KERN_ERR "stack-protector: Kernel stack is corrupted in: %p\n", | |
476 | __builtin_return_address(0)); | |
3162f751 AV |
477 | } |
478 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 479 | |
3162f751 | 480 | #endif |
f44dd164 RR |
481 | |
482 | core_param(panic, panic_timeout, int, 0644); | |
483 | core_param(pause_on_oops, pause_on_oops, int, 0644); | |
d404ab0a OH |
484 | |
485 | static int __init oops_setup(char *s) | |
486 | { | |
487 | if (!s) | |
488 | return -EINVAL; | |
489 | if (!strcmp(s, "panic")) | |
490 | panic_on_oops = 1; | |
491 | return 0; | |
492 | } | |
493 | early_param("oops", oops_setup); |