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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> |
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 | */ | |
c277e63f | 55 | |
1da177e4 LT |
56 | NORET_TYPE void panic(const char * fmt, ...) |
57 | { | |
58 | long i; | |
59 | static char buf[1024]; | |
60 | va_list args; | |
347a8dc3 | 61 | #if defined(CONFIG_S390) |
c277e63f | 62 | unsigned long caller = (unsigned long) __builtin_return_address(0); |
1da177e4 LT |
63 | #endif |
64 | ||
dc009d92 EB |
65 | /* |
66 | * It's possible to come here directly from a panic-assertion and not | |
67 | * have preempt disabled. Some functions called from here want | |
68 | * preempt to be disabled. No point enabling it later though... | |
69 | */ | |
70 | preempt_disable(); | |
71 | ||
1da177e4 LT |
72 | bust_spinlocks(1); |
73 | va_start(args, fmt); | |
74 | vsnprintf(buf, sizeof(buf), fmt, args); | |
75 | va_end(args); | |
76 | printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); | |
5cb27301 IM |
77 | #ifdef CONFIG_DEBUG_BUGVERBOSE |
78 | dump_stack(); | |
79 | #endif | |
1da177e4 LT |
80 | bust_spinlocks(0); |
81 | ||
dc009d92 EB |
82 | /* |
83 | * If we have crashed and we have a crash kernel loaded let it handle | |
84 | * everything else. | |
85 | * Do we want to call this before we try to display a message? | |
86 | */ | |
6e274d14 | 87 | crash_kexec(NULL); |
dc009d92 | 88 | |
1da177e4 | 89 | #ifdef CONFIG_SMP |
dc009d92 EB |
90 | /* |
91 | * Note smp_send_stop is the usual smp shutdown function, which | |
92 | * unfortunately means it may not be hardened to work in a panic | |
93 | * situation. | |
94 | */ | |
1da177e4 LT |
95 | smp_send_stop(); |
96 | #endif | |
97 | ||
e041c683 | 98 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 LT |
99 | |
100 | if (!panic_blink) | |
101 | panic_blink = no_blink; | |
102 | ||
dc009d92 | 103 | if (panic_timeout > 0) { |
1da177e4 LT |
104 | /* |
105 | * Delay timeout seconds before rebooting the machine. | |
106 | * We can't use the "normal" timers since we just panicked.. | |
107 | */ | |
108 | printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); | |
109 | for (i = 0; i < panic_timeout*1000; ) { | |
110 | touch_nmi_watchdog(); | |
111 | i += panic_blink(i); | |
112 | mdelay(1); | |
113 | i++; | |
114 | } | |
2f048ea8 EB |
115 | /* This will not be a clean reboot, with everything |
116 | * shutting down. But if there is a chance of | |
117 | * rebooting the system it will be rebooted. | |
1da177e4 | 118 | */ |
2f048ea8 | 119 | emergency_restart(); |
1da177e4 LT |
120 | } |
121 | #ifdef __sparc__ | |
122 | { | |
123 | extern int stop_a_enabled; | |
a271c241 | 124 | /* Make sure the user can actually press Stop-A (L1-A) */ |
1da177e4 | 125 | stop_a_enabled = 1; |
a271c241 | 126 | printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); |
1da177e4 LT |
127 | } |
128 | #endif | |
347a8dc3 | 129 | #if defined(CONFIG_S390) |
c277e63f | 130 | disabled_wait(caller); |
1da177e4 LT |
131 | #endif |
132 | local_irq_enable(); | |
133 | for (i = 0;;) { | |
c22db941 | 134 | touch_softlockup_watchdog(); |
1da177e4 LT |
135 | i += panic_blink(i); |
136 | mdelay(1); | |
137 | i++; | |
138 | } | |
139 | } | |
140 | ||
141 | EXPORT_SYMBOL(panic); | |
142 | ||
c277e63f | 143 | |
25ddbb18 AK |
144 | struct tnt { |
145 | u8 bit; | |
146 | char true; | |
147 | char false; | |
148 | }; | |
149 | ||
150 | static const struct tnt tnts[] = { | |
151 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, | |
152 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
153 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
154 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
155 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
156 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
157 | { TAINT_USER, 'U', ' ' }, | |
158 | { TAINT_DIE, 'D', ' ' }, | |
159 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
160 | { TAINT_WARN, 'W', ' ' }, | |
26e9a397 | 161 | { TAINT_CRAP, 'C', ' ' }, |
25ddbb18 AK |
162 | }; |
163 | ||
1da177e4 LT |
164 | /** |
165 | * print_tainted - return a string to represent the kernel taint state. | |
166 | * | |
167 | * 'P' - Proprietary module has been loaded. | |
168 | * 'F' - Module has been forcibly loaded. | |
169 | * 'S' - SMP with CPUs not designed for SMP. | |
170 | * 'R' - User forced a module unload. | |
9aa5e993 | 171 | * 'M' - System experienced a machine check exception. |
1da177e4 | 172 | * 'B' - System has hit bad_page. |
34f5a398 | 173 | * 'U' - Userspace-defined naughtiness. |
a8005992 | 174 | * 'D' - Kernel has oopsed before |
95b570c9 NH |
175 | * 'A' - ACPI table overridden. |
176 | * 'W' - Taint on warning. | |
061b1bd3 | 177 | * 'C' - modules from drivers/staging are loaded. |
1da177e4 LT |
178 | * |
179 | * The string is overwritten by the next call to print_taint(). | |
180 | */ | |
1da177e4 LT |
181 | const char *print_tainted(void) |
182 | { | |
25ddbb18 AK |
183 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
184 | ||
185 | if (tainted_mask) { | |
186 | char *s; | |
187 | int i; | |
188 | ||
189 | s = buf + sprintf(buf, "Tainted: "); | |
190 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
191 | const struct tnt *t = &tnts[i]; | |
192 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
193 | t->true : t->false; | |
194 | } | |
195 | *s = 0; | |
196 | } else | |
1da177e4 LT |
197 | snprintf(buf, sizeof(buf), "Not tainted"); |
198 | return(buf); | |
199 | } | |
200 | ||
25ddbb18 | 201 | int test_taint(unsigned flag) |
1da177e4 | 202 | { |
25ddbb18 AK |
203 | return test_bit(flag, &tainted_mask); |
204 | } | |
205 | EXPORT_SYMBOL(test_taint); | |
206 | ||
207 | unsigned long get_taint(void) | |
208 | { | |
209 | return tainted_mask; | |
1da177e4 | 210 | } |
dd287796 | 211 | |
1da177e4 | 212 | void add_taint(unsigned flag) |
dd287796 | 213 | { |
068c4579 | 214 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
25ddbb18 | 215 | set_bit(flag, &tainted_mask); |
dd287796 | 216 | } |
1da177e4 | 217 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
218 | |
219 | static void spin_msec(int msecs) | |
220 | { | |
221 | int i; | |
222 | ||
223 | for (i = 0; i < msecs; i++) { | |
224 | touch_nmi_watchdog(); | |
225 | mdelay(1); | |
226 | } | |
227 | } | |
228 | ||
229 | /* | |
230 | * It just happens that oops_enter() and oops_exit() are identically | |
231 | * implemented... | |
232 | */ | |
233 | static void do_oops_enter_exit(void) | |
234 | { | |
235 | unsigned long flags; | |
236 | static int spin_counter; | |
237 | ||
238 | if (!pause_on_oops) | |
239 | return; | |
240 | ||
241 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
242 | if (pause_on_oops_flag == 0) { | |
243 | /* This CPU may now print the oops message */ | |
244 | pause_on_oops_flag = 1; | |
245 | } else { | |
246 | /* We need to stall this CPU */ | |
247 | if (!spin_counter) { | |
248 | /* This CPU gets to do the counting */ | |
249 | spin_counter = pause_on_oops; | |
250 | do { | |
251 | spin_unlock(&pause_on_oops_lock); | |
252 | spin_msec(MSEC_PER_SEC); | |
253 | spin_lock(&pause_on_oops_lock); | |
254 | } while (--spin_counter); | |
255 | pause_on_oops_flag = 0; | |
256 | } else { | |
257 | /* This CPU waits for a different one */ | |
258 | while (spin_counter) { | |
259 | spin_unlock(&pause_on_oops_lock); | |
260 | spin_msec(1); | |
261 | spin_lock(&pause_on_oops_lock); | |
262 | } | |
263 | } | |
264 | } | |
265 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
266 | } | |
267 | ||
268 | /* | |
269 | * Return true if the calling CPU is allowed to print oops-related info. This | |
270 | * is a bit racy.. | |
271 | */ | |
272 | int oops_may_print(void) | |
273 | { | |
274 | return pause_on_oops_flag == 0; | |
275 | } | |
276 | ||
277 | /* | |
278 | * Called when the architecture enters its oops handler, before it prints | |
279 | * anything. If this is the first CPU to oops, and it's oopsing the first time | |
280 | * then let it proceed. | |
281 | * | |
282 | * This is all enabled by the pause_on_oops kernel boot option. We do all this | |
283 | * to ensure that oopses don't scroll off the screen. It has the side-effect | |
284 | * of preventing later-oopsing CPUs from mucking up the display, too. | |
285 | * | |
286 | * It turns out that the CPU which is allowed to print ends up pausing for the | |
287 | * right duration, whereas all the other CPUs pause for twice as long: once in | |
288 | * oops_enter(), once in oops_exit(). | |
289 | */ | |
290 | void oops_enter(void) | |
291 | { | |
2c16e9c8 | 292 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
dd287796 AM |
293 | do_oops_enter_exit(); |
294 | } | |
295 | ||
2c3b20e9 AV |
296 | /* |
297 | * 64-bit random ID for oopses: | |
298 | */ | |
299 | static u64 oops_id; | |
300 | ||
301 | static int init_oops_id(void) | |
302 | { | |
303 | if (!oops_id) | |
304 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
305 | else |
306 | oops_id++; | |
2c3b20e9 AV |
307 | |
308 | return 0; | |
309 | } | |
310 | late_initcall(init_oops_id); | |
311 | ||
71c33911 AV |
312 | static void print_oops_end_marker(void) |
313 | { | |
314 | init_oops_id(); | |
315 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
316 | (unsigned long long)oops_id); | |
317 | } | |
318 | ||
dd287796 AM |
319 | /* |
320 | * Called when the architecture exits its oops handler, after printing | |
321 | * everything. | |
322 | */ | |
323 | void oops_exit(void) | |
324 | { | |
325 | do_oops_enter_exit(); | |
71c33911 | 326 | print_oops_end_marker(); |
dd287796 | 327 | } |
3162f751 | 328 | |
79b4cc5e | 329 | #ifdef WANT_WARN_ON_SLOWPATH |
a8f18b90 AV |
330 | void warn_slowpath(const char *file, int line, const char *fmt, ...) |
331 | { | |
332 | va_list args; | |
333 | char function[KSYM_SYMBOL_LEN]; | |
334 | unsigned long caller = (unsigned long)__builtin_return_address(0); | |
bd89bb29 AV |
335 | const char *board; |
336 | ||
a8f18b90 AV |
337 | sprint_symbol(function, caller); |
338 | ||
339 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
340 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, | |
341 | line, function); | |
bd89bb29 AV |
342 | board = dmi_get_system_info(DMI_PRODUCT_NAME); |
343 | if (board) | |
344 | printk(KERN_WARNING "Hardware name: %s\n", board); | |
74853dba AV |
345 | |
346 | if (fmt) { | |
347 | va_start(args, fmt); | |
348 | vprintk(fmt, args); | |
349 | va_end(args); | |
350 | } | |
a8f18b90 AV |
351 | |
352 | print_modules(); | |
353 | dump_stack(); | |
354 | print_oops_end_marker(); | |
355 | add_taint(TAINT_WARN); | |
356 | } | |
357 | EXPORT_SYMBOL(warn_slowpath); | |
79b4cc5e AV |
358 | #endif |
359 | ||
3162f751 | 360 | #ifdef CONFIG_CC_STACKPROTECTOR |
54371a43 | 361 | |
3162f751 AV |
362 | /* |
363 | * Called when gcc's -fstack-protector feature is used, and | |
364 | * gcc detects corruption of the on-stack canary value | |
365 | */ | |
366 | void __stack_chk_fail(void) | |
367 | { | |
517a92c4 IM |
368 | panic("stack-protector: Kernel stack is corrupted in: %p\n", |
369 | __builtin_return_address(0)); | |
3162f751 AV |
370 | } |
371 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 372 | |
3162f751 | 373 | #endif |
f44dd164 RR |
374 | |
375 | core_param(panic, panic_timeout, int, 0644); | |
376 | core_param(pause_on_oops, pause_on_oops, int, 0644); |