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Commit | Line | Data |
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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 | */ | |
1da177e4 LT |
11 | #include <linux/module.h> |
12 | #include <linux/sched.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/reboot.h> | |
15 | #include <linux/notifier.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/sysrq.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/nmi.h> | |
dc009d92 | 20 | #include <linux/kexec.h> |
657b3010 | 21 | #include <linux/debug_locks.h> |
2c3b20e9 | 22 | #include <linux/random.h> |
79b4cc5e | 23 | #include <linux/kallsyms.h> |
1da177e4 | 24 | |
1da177e4 | 25 | int panic_on_oops; |
25ddbb18 | 26 | static unsigned long tainted_mask; |
dd287796 AM |
27 | static int pause_on_oops; |
28 | static int pause_on_oops_flag; | |
29 | static DEFINE_SPINLOCK(pause_on_oops_lock); | |
1da177e4 | 30 | |
dd287796 | 31 | int panic_timeout; |
1da177e4 | 32 | |
e041c683 | 33 | ATOMIC_NOTIFIER_HEAD(panic_notifier_list); |
1da177e4 LT |
34 | |
35 | EXPORT_SYMBOL(panic_notifier_list); | |
36 | ||
37 | static int __init panic_setup(char *str) | |
38 | { | |
39 | panic_timeout = simple_strtoul(str, NULL, 0); | |
40 | return 1; | |
41 | } | |
42 | __setup("panic=", panic_setup); | |
43 | ||
44 | static long no_blink(long time) | |
45 | { | |
46 | return 0; | |
47 | } | |
48 | ||
49 | /* Returns how long it waited in ms */ | |
50 | long (*panic_blink)(long time); | |
51 | EXPORT_SYMBOL(panic_blink); | |
52 | ||
53 | /** | |
54 | * panic - halt the system | |
55 | * @fmt: The text string to print | |
56 | * | |
57 | * Display a message, then perform cleanups. | |
58 | * | |
59 | * This function never returns. | |
60 | */ | |
c277e63f | 61 | |
1da177e4 LT |
62 | NORET_TYPE void panic(const char * fmt, ...) |
63 | { | |
64 | long i; | |
65 | static char buf[1024]; | |
66 | va_list args; | |
347a8dc3 | 67 | #if defined(CONFIG_S390) |
c277e63f | 68 | unsigned long caller = (unsigned long) __builtin_return_address(0); |
1da177e4 LT |
69 | #endif |
70 | ||
dc009d92 EB |
71 | /* |
72 | * It's possible to come here directly from a panic-assertion and not | |
73 | * have preempt disabled. Some functions called from here want | |
74 | * preempt to be disabled. No point enabling it later though... | |
75 | */ | |
76 | preempt_disable(); | |
77 | ||
1da177e4 LT |
78 | bust_spinlocks(1); |
79 | va_start(args, fmt); | |
80 | vsnprintf(buf, sizeof(buf), fmt, args); | |
81 | va_end(args); | |
82 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
83 | bust_spinlocks(0); | |
84 | ||
dc009d92 EB |
85 | /* |
86 | * If we have crashed and we have a crash kernel loaded let it handle | |
87 | * everything else. | |
88 | * Do we want to call this before we try to display a message? | |
89 | */ | |
6e274d14 | 90 | crash_kexec(NULL); |
dc009d92 | 91 | |
1da177e4 | 92 | #ifdef CONFIG_SMP |
dc009d92 EB |
93 | /* |
94 | * Note smp_send_stop is the usual smp shutdown function, which | |
95 | * unfortunately means it may not be hardened to work in a panic | |
96 | * situation. | |
97 | */ | |
1da177e4 LT |
98 | smp_send_stop(); |
99 | #endif | |
100 | ||
e041c683 | 101 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 LT |
102 | |
103 | if (!panic_blink) | |
104 | panic_blink = no_blink; | |
105 | ||
dc009d92 | 106 | if (panic_timeout > 0) { |
1da177e4 LT |
107 | /* |
108 | * Delay timeout seconds before rebooting the machine. | |
109 | * We can't use the "normal" timers since we just panicked.. | |
110 | */ | |
111 | printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); | |
112 | for (i = 0; i < panic_timeout*1000; ) { | |
113 | touch_nmi_watchdog(); | |
114 | i += panic_blink(i); | |
115 | mdelay(1); | |
116 | i++; | |
117 | } | |
2f048ea8 EB |
118 | /* This will not be a clean reboot, with everything |
119 | * shutting down. But if there is a chance of | |
120 | * rebooting the system it will be rebooted. | |
1da177e4 | 121 | */ |
2f048ea8 | 122 | emergency_restart(); |
1da177e4 LT |
123 | } |
124 | #ifdef __sparc__ | |
125 | { | |
126 | extern int stop_a_enabled; | |
a271c241 | 127 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 128 | stop_a_enabled = 1; |
a271c241 | 129 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
130 | } |
131 | #endif | |
347a8dc3 | 132 | #if defined(CONFIG_S390) |
c277e63f | 133 | disabled_wait(caller); |
1da177e4 LT |
134 | #endif |
135 | local_irq_enable(); | |
136 | for (i = 0;;) { | |
c22db941 | 137 | touch_softlockup_watchdog(); |
1da177e4 LT |
138 | i += panic_blink(i); |
139 | mdelay(1); | |
140 | i++; | |
141 | } | |
142 | } | |
143 | ||
144 | EXPORT_SYMBOL(panic); | |
145 | ||
c277e63f | 146 | |
25ddbb18 AK |
147 | struct tnt { |
148 | u8 bit; | |
149 | char true; | |
150 | char false; | |
151 | }; | |
152 | ||
153 | static const struct tnt tnts[] = { | |
154 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, | |
155 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
156 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
157 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
158 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
159 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
160 | { TAINT_USER, 'U', ' ' }, | |
161 | { TAINT_DIE, 'D', ' ' }, | |
162 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
163 | { TAINT_WARN, 'W', ' ' }, | |
26e9a397 | 164 | { TAINT_CRAP, 'C', ' ' }, |
25ddbb18 AK |
165 | }; |
166 | ||
6d5cd6ef RD |
167 | /** |
168 | * print_tainted - return a string to represent the kernel taint state. | |
169 | * | |
170 | * 'P' - Proprietary module has been loaded. | |
171 | * 'F' - Module has been forcibly loaded. | |
172 | * 'S' - SMP with CPUs not designed for SMP. | |
173 | * 'R' - User forced a module unload. | |
174 | * 'M' - System experienced a machine check exception. | |
175 | * 'B' - System has hit bad_page. | |
176 | * 'U' - Userspace-defined naughtiness. | |
177 | * 'A' - ACPI table overridden. | |
178 | * 'W' - Taint on warning. | |
061b1bd3 | 179 | * 'C' - modules from drivers/staging are loaded. |
6d5cd6ef RD |
180 | * |
181 | * The string is overwritten by the next call to print_taint(). | |
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 LT |
199 | snprintf(buf, sizeof(buf), "Not tainted"); |
200 | return(buf); | |
201 | } | |
202 | ||
25ddbb18 AK |
203 | int test_taint(unsigned flag) |
204 | { | |
205 | return test_bit(flag, &tainted_mask); | |
206 | } | |
207 | EXPORT_SYMBOL(test_taint); | |
208 | ||
209 | unsigned long get_taint(void) | |
210 | { | |
211 | return tainted_mask; | |
212 | } | |
213 | ||
1da177e4 LT |
214 | void add_taint(unsigned flag) |
215 | { | |
068c4579 | 216 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
25ddbb18 | 217 | set_bit(flag, &tainted_mask); |
1da177e4 LT |
218 | } |
219 | EXPORT_SYMBOL(add_taint); | |
dd287796 AM |
220 | |
221 | static int __init pause_on_oops_setup(char *str) | |
222 | { | |
223 | pause_on_oops = simple_strtoul(str, NULL, 0); | |
224 | return 1; | |
225 | } | |
226 | __setup("pause_on_oops=", pause_on_oops_setup); | |
227 | ||
228 | static void spin_msec(int msecs) | |
229 | { | |
230 | int i; | |
231 | ||
232 | for (i = 0; i < msecs; i++) { | |
233 | touch_nmi_watchdog(); | |
234 | mdelay(1); | |
235 | } | |
236 | } | |
237 | ||
238 | /* | |
239 | * It just happens that oops_enter() and oops_exit() are identically | |
240 | * implemented... | |
241 | */ | |
242 | static void do_oops_enter_exit(void) | |
243 | { | |
244 | unsigned long flags; | |
245 | static int spin_counter; | |
246 | ||
247 | if (!pause_on_oops) | |
248 | return; | |
249 | ||
250 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
251 | if (pause_on_oops_flag == 0) { | |
252 | /* This CPU may now print the oops message */ | |
253 | pause_on_oops_flag = 1; | |
254 | } else { | |
255 | /* We need to stall this CPU */ | |
256 | if (!spin_counter) { | |
257 | /* This CPU gets to do the counting */ | |
258 | spin_counter = pause_on_oops; | |
259 | do { | |
260 | spin_unlock(&pause_on_oops_lock); | |
261 | spin_msec(MSEC_PER_SEC); | |
262 | spin_lock(&pause_on_oops_lock); | |
263 | } while (--spin_counter); | |
264 | pause_on_oops_flag = 0; | |
265 | } else { | |
266 | /* This CPU waits for a different one */ | |
267 | while (spin_counter) { | |
268 | spin_unlock(&pause_on_oops_lock); | |
269 | spin_msec(1); | |
270 | spin_lock(&pause_on_oops_lock); | |
271 | } | |
272 | } | |
273 | } | |
274 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
275 | } | |
276 | ||
277 | /* | |
278 | * Return true if the calling CPU is allowed to print oops-related info. This | |
279 | * is a bit racy.. | |
280 | */ | |
281 | int oops_may_print(void) | |
282 | { | |
283 | return pause_on_oops_flag == 0; | |
284 | } | |
285 | ||
286 | /* | |
287 | * Called when the architecture enters its oops handler, before it prints | |
288 | * anything. If this is the first CPU to oops, and it's oopsing the first time | |
289 | * then let it proceed. | |
290 | * | |
291 | * This is all enabled by the pause_on_oops kernel boot option. We do all this | |
292 | * to ensure that oopses don't scroll off the screen. It has the side-effect | |
293 | * of preventing later-oopsing CPUs from mucking up the display, too. | |
294 | * | |
295 | * It turns out that the CPU which is allowed to print ends up pausing for the | |
296 | * right duration, whereas all the other CPUs pause for twice as long: once in | |
297 | * oops_enter(), once in oops_exit(). | |
298 | */ | |
299 | void oops_enter(void) | |
300 | { | |
2c16e9c8 | 301 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
dd287796 AM |
302 | do_oops_enter_exit(); |
303 | } | |
304 | ||
2c3b20e9 AV |
305 | /* |
306 | * 64-bit random ID for oopses: | |
307 | */ | |
308 | static u64 oops_id; | |
309 | ||
310 | static int init_oops_id(void) | |
311 | { | |
312 | if (!oops_id) | |
313 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
314 | ||
315 | return 0; | |
316 | } | |
317 | late_initcall(init_oops_id); | |
318 | ||
71c33911 AV |
319 | static void print_oops_end_marker(void) |
320 | { | |
321 | init_oops_id(); | |
322 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
323 | (unsigned long long)oops_id); | |
324 | } | |
325 | ||
dd287796 AM |
326 | /* |
327 | * Called when the architecture exits its oops handler, after printing | |
328 | * everything. | |
329 | */ | |
330 | void oops_exit(void) | |
331 | { | |
332 | do_oops_enter_exit(); | |
71c33911 | 333 | print_oops_end_marker(); |
dd287796 | 334 | } |
3162f751 | 335 | |
79b4cc5e AV |
336 | #ifdef WANT_WARN_ON_SLOWPATH |
337 | void warn_on_slowpath(const char *file, int line) | |
338 | { | |
339 | char function[KSYM_SYMBOL_LEN]; | |
340 | unsigned long caller = (unsigned long) __builtin_return_address(0); | |
79b4cc5e | 341 | sprint_symbol(function, caller); |
71c33911 AV |
342 | |
343 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
79b4cc5e AV |
344 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, |
345 | line, function); | |
71c33911 | 346 | print_modules(); |
79b4cc5e | 347 | dump_stack(); |
71c33911 | 348 | print_oops_end_marker(); |
95b570c9 | 349 | add_taint(TAINT_WARN); |
79b4cc5e AV |
350 | } |
351 | EXPORT_SYMBOL(warn_on_slowpath); | |
a8f18b90 AV |
352 | |
353 | ||
354 | void warn_slowpath(const char *file, int line, const char *fmt, ...) | |
355 | { | |
356 | va_list args; | |
357 | char function[KSYM_SYMBOL_LEN]; | |
358 | unsigned long caller = (unsigned long)__builtin_return_address(0); | |
359 | sprint_symbol(function, caller); | |
360 | ||
361 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
362 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, | |
363 | line, function); | |
364 | va_start(args, fmt); | |
365 | vprintk(fmt, args); | |
366 | va_end(args); | |
367 | ||
368 | print_modules(); | |
369 | dump_stack(); | |
370 | print_oops_end_marker(); | |
371 | add_taint(TAINT_WARN); | |
372 | } | |
373 | EXPORT_SYMBOL(warn_slowpath); | |
79b4cc5e AV |
374 | #endif |
375 | ||
3162f751 AV |
376 | #ifdef CONFIG_CC_STACKPROTECTOR |
377 | /* | |
378 | * Called when gcc's -fstack-protector feature is used, and | |
379 | * gcc detects corruption of the on-stack canary value | |
380 | */ | |
381 | void __stack_chk_fail(void) | |
382 | { | |
383 | panic("stack-protector: Kernel stack is corrupted"); | |
384 | } | |
385 | EXPORT_SYMBOL(__stack_chk_fail); | |
386 | #endif |