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> | |
13 | #include <linux/kallsyms.h> | |
14 | #include <linux/notifier.h> | |
1da177e4 | 15 | #include <linux/module.h> |
c95dbf27 | 16 | #include <linux/random.h> |
1da177e4 | 17 | #include <linux/reboot.h> |
c95dbf27 IM |
18 | #include <linux/delay.h> |
19 | #include <linux/kexec.h> | |
20 | #include <linux/sched.h> | |
1da177e4 | 21 | #include <linux/sysrq.h> |
c95dbf27 | 22 | #include <linux/init.h> |
1da177e4 | 23 | #include <linux/nmi.h> |
bd89bb29 | 24 | #include <linux/dmi.h> |
1da177e4 | 25 | |
1da177e4 | 26 | int panic_on_oops; |
25ddbb18 | 27 | static unsigned long tainted_mask; |
dd287796 AM |
28 | static int pause_on_oops; |
29 | static int pause_on_oops_flag; | |
30 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
1da177e4 | 31 | |
dd287796 | 32 | int panic_timeout; |
1da177e4 | 33 | |
e041c683 | 34 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
35 | |
36 | EXPORT_SYMBOL(panic_notifier_list); | |
37 | ||
1da177e4 LT |
38 | static long no_blink(long time) |
39 | { | |
40 | return 0; | |
41 | } | |
42 | ||
43 | /* Returns how long it waited in ms */ | |
44 | long (*panic_blink)(long time); | |
45 | EXPORT_SYMBOL(panic_blink); | |
46 | ||
47 | /** | |
48 | * panic - halt the system | |
49 | * @fmt: The text string to print | |
50 | * | |
51 | * Display a message, then perform cleanups. | |
52 | * | |
53 | * This function never returns. | |
54 | */ | |
1da177e4 LT |
55 | NORET_TYPE void panic(const char * fmt, ...) |
56 | { | |
1da177e4 LT |
57 | static char buf[1024]; |
58 | va_list args; | |
c95dbf27 | 59 | long i; |
1da177e4 | 60 | |
dc009d92 | 61 | /* |
c95dbf27 IM |
62 | * It's possible to come here directly from a panic-assertion and |
63 | * not have preempt disabled. Some functions called from here want | |
dc009d92 EB |
64 | * preempt to be disabled. No point enabling it later though... |
65 | */ | |
66 | preempt_disable(); | |
67 | ||
1da177e4 LT |
68 | bust_spinlocks(1); |
69 | va_start(args, fmt); | |
70 | vsnprintf(buf, sizeof(buf), fmt, args); | |
71 | va_end(args); | |
72 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
5cb27301 IM |
73 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
74 | dump_stack(); | |
75 | #endif | |
1da177e4 | 76 | |
dc009d92 EB |
77 | /* |
78 | * If we have crashed and we have a crash kernel loaded let it handle | |
79 | * everything else. | |
80 | * Do we want to call this before we try to display a message? | |
81 | */ | |
6e274d14 | 82 | crash_kexec(NULL); |
dc009d92 | 83 | |
dc009d92 EB |
84 | /* |
85 | * Note smp_send_stop is the usual smp shutdown function, which | |
86 | * unfortunately means it may not be hardened to work in a panic | |
87 | * situation. | |
88 | */ | |
1da177e4 | 89 | smp_send_stop(); |
1da177e4 | 90 | |
e041c683 | 91 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 | 92 | |
d014e889 AK |
93 | bust_spinlocks(0); |
94 | ||
1da177e4 LT |
95 | if (!panic_blink) |
96 | panic_blink = no_blink; | |
97 | ||
dc009d92 | 98 | if (panic_timeout > 0) { |
1da177e4 | 99 | /* |
c95dbf27 IM |
100 | * Delay timeout seconds before rebooting the machine. |
101 | * We can't use the "normal" timers since we just panicked. | |
102 | */ | |
103 | printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout); | |
104 | ||
1da177e4 LT |
105 | for (i = 0; i < panic_timeout*1000; ) { |
106 | touch_nmi_watchdog(); | |
107 | i += panic_blink(i); | |
108 | mdelay(1); | |
109 | i++; | |
110 | } | |
c95dbf27 IM |
111 | /* |
112 | * This will not be a clean reboot, with everything | |
113 | * shutting down. But if there is a chance of | |
114 | * rebooting the system it will be rebooted. | |
1da177e4 | 115 | */ |
2f048ea8 | 116 | emergency_restart(); |
1da177e4 LT |
117 | } |
118 | #ifdef __sparc__ | |
119 | { | |
120 | extern int stop_a_enabled; | |
a271c241 | 121 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 122 | stop_a_enabled = 1; |
a271c241 | 123 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
124 | } |
125 | #endif | |
347a8dc3 | 126 | #if defined(CONFIG_S390) |
c95dbf27 IM |
127 | { |
128 | unsigned long caller; | |
129 | ||
130 | caller = (unsigned long)__builtin_return_address(0); | |
131 | disabled_wait(caller); | |
132 | } | |
1da177e4 LT |
133 | #endif |
134 | local_irq_enable(); | |
c95dbf27 | 135 | for (i = 0; ; ) { |
c22db941 | 136 | touch_softlockup_watchdog(); |
1da177e4 LT |
137 | i += panic_blink(i); |
138 | mdelay(1); | |
139 | i++; | |
140 | } | |
141 | } | |
142 | ||
143 | EXPORT_SYMBOL(panic); | |
144 | ||
c277e63f | 145 | |
25ddbb18 | 146 | struct tnt { |
c95dbf27 IM |
147 | u8 bit; |
148 | char true; | |
149 | char false; | |
25ddbb18 AK |
150 | }; |
151 | ||
152 | static const struct tnt tnts[] = { | |
c95dbf27 IM |
153 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, |
154 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
155 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
156 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
157 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
158 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
159 | { TAINT_USER, 'U', ' ' }, | |
160 | { TAINT_DIE, 'D', ' ' }, | |
161 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
162 | { TAINT_WARN, 'W', ' ' }, | |
163 | { TAINT_CRAP, 'C', ' ' }, | |
25ddbb18 AK |
164 | }; |
165 | ||
1da177e4 LT |
166 | /** |
167 | * print_tainted - return a string to represent the kernel taint state. | |
168 | * | |
169 | * 'P' - Proprietary module has been loaded. | |
170 | * 'F' - Module has been forcibly loaded. | |
171 | * 'S' - SMP with CPUs not designed for SMP. | |
172 | * 'R' - User forced a module unload. | |
9aa5e993 | 173 | * 'M' - System experienced a machine check exception. |
1da177e4 | 174 | * 'B' - System has hit bad_page. |
34f5a398 | 175 | * 'U' - Userspace-defined naughtiness. |
a8005992 | 176 | * 'D' - Kernel has oopsed before |
95b570c9 NH |
177 | * 'A' - ACPI table overridden. |
178 | * 'W' - Taint on warning. | |
061b1bd3 | 179 | * 'C' - modules from drivers/staging are loaded. |
1da177e4 | 180 | * |
fe002a41 | 181 | * The string is overwritten by the next call to print_tainted(). |
1da177e4 | 182 | */ |
1da177e4 LT |
183 | const char *print_tainted(void) |
184 | { | |
25ddbb18 AK |
185 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
186 | ||
187 | if (tainted_mask) { | |
188 | char *s; | |
189 | int i; | |
190 | ||
191 | s = buf + sprintf(buf, "Tainted: "); | |
192 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
193 | const struct tnt *t = &tnts[i]; | |
194 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
195 | t->true : t->false; | |
196 | } | |
197 | *s = 0; | |
198 | } else | |
1da177e4 | 199 | snprintf(buf, sizeof(buf), "Not tainted"); |
c95dbf27 IM |
200 | |
201 | return buf; | |
1da177e4 LT |
202 | } |
203 | ||
25ddbb18 | 204 | int test_taint(unsigned flag) |
1da177e4 | 205 | { |
25ddbb18 AK |
206 | return test_bit(flag, &tainted_mask); |
207 | } | |
208 | EXPORT_SYMBOL(test_taint); | |
209 | ||
210 | unsigned long get_taint(void) | |
211 | { | |
212 | return tainted_mask; | |
1da177e4 | 213 | } |
dd287796 | 214 | |
1da177e4 | 215 | void add_taint(unsigned flag) |
dd287796 | 216 | { |
9eeba613 FW |
217 | /* |
218 | * Can't trust the integrity of the kernel anymore. | |
219 | * We don't call directly debug_locks_off() because the issue | |
220 | * is not necessarily serious enough to set oops_in_progress to 1 | |
574bbe78 FW |
221 | * Also we want to keep up lockdep for staging development and |
222 | * post-warning case. | |
9eeba613 | 223 | */ |
574bbe78 | 224 | if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off()) |
b48ccb09 | 225 | printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n"); |
9eeba613 | 226 | |
25ddbb18 | 227 | set_bit(flag, &tainted_mask); |
dd287796 | 228 | } |
1da177e4 | 229 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
230 | |
231 | static void spin_msec(int msecs) | |
232 | { | |
233 | int i; | |
234 | ||
235 | for (i = 0; i < msecs; i++) { | |
236 | touch_nmi_watchdog(); | |
237 | mdelay(1); | |
238 | } | |
239 | } | |
240 | ||
241 | /* | |
242 | * It just happens that oops_enter() and oops_exit() are identically | |
243 | * implemented... | |
244 | */ | |
245 | static void do_oops_enter_exit(void) | |
246 | { | |
247 | unsigned long flags; | |
248 | static int spin_counter; | |
249 | ||
250 | if (!pause_on_oops) | |
251 | return; | |
252 | ||
253 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
254 | if (pause_on_oops_flag == 0) { | |
255 | /* This CPU may now print the oops message */ | |
256 | pause_on_oops_flag = 1; | |
257 | } else { | |
258 | /* We need to stall this CPU */ | |
259 | if (!spin_counter) { | |
260 | /* This CPU gets to do the counting */ | |
261 | spin_counter = pause_on_oops; | |
262 | do { | |
263 | spin_unlock(&pause_on_oops_lock); | |
264 | spin_msec(MSEC_PER_SEC); | |
265 | spin_lock(&pause_on_oops_lock); | |
266 | } while (--spin_counter); | |
267 | pause_on_oops_flag = 0; | |
268 | } else { | |
269 | /* This CPU waits for a different one */ | |
270 | while (spin_counter) { | |
271 | spin_unlock(&pause_on_oops_lock); | |
272 | spin_msec(1); | |
273 | spin_lock(&pause_on_oops_lock); | |
274 | } | |
275 | } | |
276 | } | |
277 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
278 | } | |
279 | ||
280 | /* | |
c95dbf27 IM |
281 | * Return true if the calling CPU is allowed to print oops-related info. |
282 | * This is a bit racy.. | |
dd287796 AM |
283 | */ |
284 | int oops_may_print(void) | |
285 | { | |
286 | return pause_on_oops_flag == 0; | |
287 | } | |
288 | ||
289 | /* | |
290 | * Called when the architecture enters its oops handler, before it prints | |
c95dbf27 IM |
291 | * anything. If this is the first CPU to oops, and it's oopsing the first |
292 | * time then let it proceed. | |
dd287796 | 293 | * |
c95dbf27 IM |
294 | * This is all enabled by the pause_on_oops kernel boot option. We do all |
295 | * this to ensure that oopses don't scroll off the screen. It has the | |
296 | * side-effect of preventing later-oopsing CPUs from mucking up the display, | |
297 | * too. | |
dd287796 | 298 | * |
c95dbf27 IM |
299 | * It turns out that the CPU which is allowed to print ends up pausing for |
300 | * the right duration, whereas all the other CPUs pause for twice as long: | |
301 | * once in oops_enter(), once in oops_exit(). | |
dd287796 AM |
302 | */ |
303 | void oops_enter(void) | |
304 | { | |
bdff7870 | 305 | tracing_off(); |
c95dbf27 IM |
306 | /* can't trust the integrity of the kernel anymore: */ |
307 | debug_locks_off(); | |
dd287796 AM |
308 | do_oops_enter_exit(); |
309 | } | |
310 | ||
2c3b20e9 AV |
311 | /* |
312 | * 64-bit random ID for oopses: | |
313 | */ | |
314 | static u64 oops_id; | |
315 | ||
316 | static int init_oops_id(void) | |
317 | { | |
318 | if (!oops_id) | |
319 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
320 | else |
321 | oops_id++; | |
2c3b20e9 AV |
322 | |
323 | return 0; | |
324 | } | |
325 | late_initcall(init_oops_id); | |
326 | ||
71c33911 AV |
327 | static void print_oops_end_marker(void) |
328 | { | |
329 | init_oops_id(); | |
330 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
331 | (unsigned long long)oops_id); | |
332 | } | |
333 | ||
dd287796 AM |
334 | /* |
335 | * Called when the architecture exits its oops handler, after printing | |
336 | * everything. | |
337 | */ | |
338 | void oops_exit(void) | |
339 | { | |
340 | do_oops_enter_exit(); | |
71c33911 | 341 | print_oops_end_marker(); |
dd287796 | 342 | } |
3162f751 | 343 | |
79b4cc5e | 344 | #ifdef WANT_WARN_ON_SLOWPATH |
0f6f49a8 LT |
345 | struct slowpath_args { |
346 | const char *fmt; | |
a8f18b90 | 347 | va_list args; |
0f6f49a8 | 348 | }; |
bd89bb29 | 349 | |
0f6f49a8 LT |
350 | static void warn_slowpath_common(const char *file, int line, void *caller, struct slowpath_args *args) |
351 | { | |
352 | const char *board; | |
a8f18b90 AV |
353 | |
354 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
0f6f49a8 | 355 | printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller); |
bd89bb29 AV |
356 | board = dmi_get_system_info(DMI_PRODUCT_NAME); |
357 | if (board) | |
358 | printk(KERN_WARNING "Hardware name: %s\n", board); | |
74853dba | 359 | |
0f6f49a8 LT |
360 | if (args) |
361 | vprintk(args->fmt, args->args); | |
a8f18b90 AV |
362 | |
363 | print_modules(); | |
364 | dump_stack(); | |
365 | print_oops_end_marker(); | |
366 | add_taint(TAINT_WARN); | |
367 | } | |
0f6f49a8 LT |
368 | |
369 | void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) | |
370 | { | |
371 | struct slowpath_args args; | |
372 | ||
373 | args.fmt = fmt; | |
374 | va_start(args.args, fmt); | |
375 | warn_slowpath_common(file, line, __builtin_return_address(0), &args); | |
376 | va_end(args.args); | |
377 | } | |
57adc4d2 AK |
378 | EXPORT_SYMBOL(warn_slowpath_fmt); |
379 | ||
380 | void warn_slowpath_null(const char *file, int line) | |
381 | { | |
0f6f49a8 | 382 | warn_slowpath_common(file, line, __builtin_return_address(0), NULL); |
57adc4d2 AK |
383 | } |
384 | EXPORT_SYMBOL(warn_slowpath_null); | |
79b4cc5e AV |
385 | #endif |
386 | ||
3162f751 | 387 | #ifdef CONFIG_CC_STACKPROTECTOR |
54371a43 | 388 | |
3162f751 AV |
389 | /* |
390 | * Called when gcc's -fstack-protector feature is used, and | |
391 | * gcc detects corruption of the on-stack canary value | |
392 | */ | |
393 | void __stack_chk_fail(void) | |
394 | { | |
517a92c4 IM |
395 | panic("stack-protector: Kernel stack is corrupted in: %p\n", |
396 | __builtin_return_address(0)); | |
3162f751 AV |
397 | } |
398 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 399 | |
3162f751 | 400 | #endif |
f44dd164 RR |
401 | |
402 | core_param(panic, panic_timeout, int, 0644); | |
403 | core_param(pause_on_oops, pause_on_oops, int, 0644); |