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 | */ | |
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 | ||
1da177e4 LT |
37 | static long no_blink(long time) |
38 | { | |
39 | return 0; | |
40 | } | |
41 | ||
42 | /* Returns how long it waited in ms */ | |
43 | long (*panic_blink)(long time); | |
44 | EXPORT_SYMBOL(panic_blink); | |
45 | ||
46 | /** | |
47 | * panic - halt the system | |
48 | * @fmt: The text string to print | |
49 | * | |
50 | * Display a message, then perform cleanups. | |
51 | * | |
52 | * This function never returns. | |
53 | */ | |
c277e63f | 54 | |
1da177e4 LT |
55 | NORET_TYPE void panic(const char * fmt, ...) |
56 | { | |
57 | long i; | |
58 | static char buf[1024]; | |
59 | va_list args; | |
347a8dc3 | 60 | #if defined(CONFIG_S390) |
c277e63f | 61 | unsigned long caller = (unsigned long) __builtin_return_address(0); |
1da177e4 LT |
62 | #endif |
63 | ||
dc009d92 EB |
64 | /* |
65 | * It's possible to come here directly from a panic-assertion and not | |
66 | * have preempt disabled. Some functions called from here want | |
67 | * preempt to be disabled. No point enabling it later though... | |
68 | */ | |
69 | preempt_disable(); | |
70 | ||
1da177e4 LT |
71 | bust_spinlocks(1); |
72 | va_start(args, fmt); | |
73 | vsnprintf(buf, sizeof(buf), fmt, args); | |
74 | va_end(args); | |
75 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
76 | bust_spinlocks(0); | |
77 | ||
dc009d92 EB |
78 | /* |
79 | * If we have crashed and we have a crash kernel loaded let it handle | |
80 | * everything else. | |
81 | * Do we want to call this before we try to display a message? | |
82 | */ | |
6e274d14 | 83 | crash_kexec(NULL); |
dc009d92 | 84 | |
1da177e4 | 85 | #ifdef CONFIG_SMP |
dc009d92 EB |
86 | /* |
87 | * Note smp_send_stop is the usual smp shutdown function, which | |
88 | * unfortunately means it may not be hardened to work in a panic | |
89 | * situation. | |
90 | */ | |
1da177e4 LT |
91 | smp_send_stop(); |
92 | #endif | |
93 | ||
e041c683 | 94 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 LT |
95 | |
96 | if (!panic_blink) | |
97 | panic_blink = no_blink; | |
98 | ||
dc009d92 | 99 | if (panic_timeout > 0) { |
1da177e4 LT |
100 | /* |
101 | * Delay timeout seconds before rebooting the machine. | |
102 | * We can't use the "normal" timers since we just panicked.. | |
103 | */ | |
104 | printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); | |
105 | for (i = 0; i < panic_timeout*1000; ) { | |
106 | touch_nmi_watchdog(); | |
107 | i += panic_blink(i); | |
108 | mdelay(1); | |
109 | i++; | |
110 | } | |
2f048ea8 EB |
111 | /* This will not be a clean reboot, with everything |
112 | * shutting down. But if there is a chance of | |
113 | * rebooting the system it will be rebooted. | |
1da177e4 | 114 | */ |
2f048ea8 | 115 | emergency_restart(); |
1da177e4 LT |
116 | } |
117 | #ifdef __sparc__ | |
118 | { | |
119 | extern int stop_a_enabled; | |
a271c241 | 120 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 121 | stop_a_enabled = 1; |
a271c241 | 122 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
123 | } |
124 | #endif | |
347a8dc3 | 125 | #if defined(CONFIG_S390) |
c277e63f | 126 | disabled_wait(caller); |
1da177e4 LT |
127 | #endif |
128 | local_irq_enable(); | |
129 | for (i = 0;;) { | |
c22db941 | 130 | touch_softlockup_watchdog(); |
1da177e4 LT |
131 | i += panic_blink(i); |
132 | mdelay(1); | |
133 | i++; | |
134 | } | |
135 | } | |
136 | ||
137 | EXPORT_SYMBOL(panic); | |
138 | ||
c277e63f | 139 | |
25ddbb18 AK |
140 | struct tnt { |
141 | u8 bit; | |
142 | char true; | |
143 | char false; | |
144 | }; | |
145 | ||
146 | static const struct tnt tnts[] = { | |
147 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, | |
148 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
149 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
150 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
151 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
152 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
153 | { TAINT_USER, 'U', ' ' }, | |
154 | { TAINT_DIE, 'D', ' ' }, | |
155 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
156 | { TAINT_WARN, 'W', ' ' }, | |
26e9a397 | 157 | { TAINT_CRAP, 'C', ' ' }, |
25ddbb18 AK |
158 | }; |
159 | ||
6d5cd6ef RD |
160 | /** |
161 | * print_tainted - return a string to represent the kernel taint state. | |
162 | * | |
163 | * 'P' - Proprietary module has been loaded. | |
164 | * 'F' - Module has been forcibly loaded. | |
165 | * 'S' - SMP with CPUs not designed for SMP. | |
166 | * 'R' - User forced a module unload. | |
167 | * 'M' - System experienced a machine check exception. | |
168 | * 'B' - System has hit bad_page. | |
169 | * 'U' - Userspace-defined naughtiness. | |
a8005992 | 170 | * 'D' - Kernel has oopsed before |
6d5cd6ef RD |
171 | * 'A' - ACPI table overridden. |
172 | * 'W' - Taint on warning. | |
061b1bd3 | 173 | * 'C' - modules from drivers/staging are loaded. |
6d5cd6ef RD |
174 | * |
175 | * The string is overwritten by the next call to print_taint(). | |
176 | */ | |
1da177e4 LT |
177 | const char *print_tainted(void) |
178 | { | |
25ddbb18 AK |
179 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
180 | ||
181 | if (tainted_mask) { | |
182 | char *s; | |
183 | int i; | |
184 | ||
185 | s = buf + sprintf(buf, "Tainted: "); | |
186 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
187 | const struct tnt *t = &tnts[i]; | |
188 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
189 | t->true : t->false; | |
190 | } | |
191 | *s = 0; | |
192 | } else | |
1da177e4 LT |
193 | snprintf(buf, sizeof(buf), "Not tainted"); |
194 | return(buf); | |
195 | } | |
196 | ||
25ddbb18 AK |
197 | int test_taint(unsigned flag) |
198 | { | |
199 | return test_bit(flag, &tainted_mask); | |
200 | } | |
201 | EXPORT_SYMBOL(test_taint); | |
202 | ||
203 | unsigned long get_taint(void) | |
204 | { | |
205 | return tainted_mask; | |
206 | } | |
207 | ||
1da177e4 LT |
208 | void add_taint(unsigned flag) |
209 | { | |
068c4579 | 210 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
25ddbb18 | 211 | set_bit(flag, &tainted_mask); |
1da177e4 LT |
212 | } |
213 | EXPORT_SYMBOL(add_taint); | |
dd287796 | 214 | |
dd287796 AM |
215 | static void spin_msec(int msecs) |
216 | { | |
217 | int i; | |
218 | ||
219 | for (i = 0; i < msecs; i++) { | |
220 | touch_nmi_watchdog(); | |
221 | mdelay(1); | |
222 | } | |
223 | } | |
224 | ||
225 | /* | |
226 | * It just happens that oops_enter() and oops_exit() are identically | |
227 | * implemented... | |
228 | */ | |
229 | static void do_oops_enter_exit(void) | |
230 | { | |
231 | unsigned long flags; | |
232 | static int spin_counter; | |
233 | ||
234 | if (!pause_on_oops) | |
235 | return; | |
236 | ||
237 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
238 | if (pause_on_oops_flag == 0) { | |
239 | /* This CPU may now print the oops message */ | |
240 | pause_on_oops_flag = 1; | |
241 | } else { | |
242 | /* We need to stall this CPU */ | |
243 | if (!spin_counter) { | |
244 | /* This CPU gets to do the counting */ | |
245 | spin_counter = pause_on_oops; | |
246 | do { | |
247 | spin_unlock(&pause_on_oops_lock); | |
248 | spin_msec(MSEC_PER_SEC); | |
249 | spin_lock(&pause_on_oops_lock); | |
250 | } while (--spin_counter); | |
251 | pause_on_oops_flag = 0; | |
252 | } else { | |
253 | /* This CPU waits for a different one */ | |
254 | while (spin_counter) { | |
255 | spin_unlock(&pause_on_oops_lock); | |
256 | spin_msec(1); | |
257 | spin_lock(&pause_on_oops_lock); | |
258 | } | |
259 | } | |
260 | } | |
261 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
262 | } | |
263 | ||
264 | /* | |
265 | * Return true if the calling CPU is allowed to print oops-related info. This | |
266 | * is a bit racy.. | |
267 | */ | |
268 | int oops_may_print(void) | |
269 | { | |
270 | return pause_on_oops_flag == 0; | |
271 | } | |
272 | ||
273 | /* | |
274 | * Called when the architecture enters its oops handler, before it prints | |
275 | * anything. If this is the first CPU to oops, and it's oopsing the first time | |
276 | * then let it proceed. | |
277 | * | |
278 | * This is all enabled by the pause_on_oops kernel boot option. We do all this | |
279 | * to ensure that oopses don't scroll off the screen. It has the side-effect | |
280 | * of preventing later-oopsing CPUs from mucking up the display, too. | |
281 | * | |
282 | * It turns out that the CPU which is allowed to print ends up pausing for the | |
283 | * right duration, whereas all the other CPUs pause for twice as long: once in | |
284 | * oops_enter(), once in oops_exit(). | |
285 | */ | |
286 | void oops_enter(void) | |
287 | { | |
2c16e9c8 | 288 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
dd287796 AM |
289 | do_oops_enter_exit(); |
290 | } | |
291 | ||
2c3b20e9 AV |
292 | /* |
293 | * 64-bit random ID for oopses: | |
294 | */ | |
295 | static u64 oops_id; | |
296 | ||
297 | static int init_oops_id(void) | |
298 | { | |
299 | if (!oops_id) | |
300 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
301 | ||
302 | return 0; | |
303 | } | |
304 | late_initcall(init_oops_id); | |
305 | ||
71c33911 AV |
306 | static void print_oops_end_marker(void) |
307 | { | |
308 | init_oops_id(); | |
309 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
310 | (unsigned long long)oops_id); | |
311 | } | |
312 | ||
dd287796 AM |
313 | /* |
314 | * Called when the architecture exits its oops handler, after printing | |
315 | * everything. | |
316 | */ | |
317 | void oops_exit(void) | |
318 | { | |
319 | do_oops_enter_exit(); | |
71c33911 | 320 | print_oops_end_marker(); |
dd287796 | 321 | } |
3162f751 | 322 | |
79b4cc5e AV |
323 | #ifdef WANT_WARN_ON_SLOWPATH |
324 | void warn_on_slowpath(const char *file, int line) | |
325 | { | |
326 | char function[KSYM_SYMBOL_LEN]; | |
327 | unsigned long caller = (unsigned long) __builtin_return_address(0); | |
79b4cc5e | 328 | sprint_symbol(function, caller); |
71c33911 AV |
329 | |
330 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
79b4cc5e AV |
331 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, |
332 | line, function); | |
71c33911 | 333 | print_modules(); |
79b4cc5e | 334 | dump_stack(); |
71c33911 | 335 | print_oops_end_marker(); |
95b570c9 | 336 | add_taint(TAINT_WARN); |
79b4cc5e AV |
337 | } |
338 | EXPORT_SYMBOL(warn_on_slowpath); | |
a8f18b90 AV |
339 | |
340 | ||
341 | void warn_slowpath(const char *file, int line, const char *fmt, ...) | |
342 | { | |
343 | va_list args; | |
344 | char function[KSYM_SYMBOL_LEN]; | |
345 | unsigned long caller = (unsigned long)__builtin_return_address(0); | |
346 | sprint_symbol(function, caller); | |
347 | ||
348 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
349 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, | |
350 | line, function); | |
351 | va_start(args, fmt); | |
352 | vprintk(fmt, args); | |
353 | va_end(args); | |
354 | ||
355 | print_modules(); | |
356 | dump_stack(); | |
357 | print_oops_end_marker(); | |
358 | add_taint(TAINT_WARN); | |
359 | } | |
360 | EXPORT_SYMBOL(warn_slowpath); | |
79b4cc5e AV |
361 | #endif |
362 | ||
3162f751 AV |
363 | #ifdef CONFIG_CC_STACKPROTECTOR |
364 | /* | |
365 | * Called when gcc's -fstack-protector feature is used, and | |
366 | * gcc detects corruption of the on-stack canary value | |
367 | */ | |
368 | void __stack_chk_fail(void) | |
369 | { | |
370 | panic("stack-protector: Kernel stack is corrupted"); | |
371 | } | |
372 | EXPORT_SYMBOL(__stack_chk_fail); | |
373 | #endif | |
f44dd164 RR |
374 | |
375 | core_param(panic, panic_timeout, int, 0644); | |
376 | core_param(pause_on_oops, pause_on_oops, int, 0644); |