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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 | 80 | |
dc009d92 EB |
81 | /* |
82 | * If we have crashed and we have a crash kernel loaded let it handle | |
83 | * everything else. | |
84 | * Do we want to call this before we try to display a message? | |
85 | */ | |
6e274d14 | 86 | crash_kexec(NULL); |
dc009d92 | 87 | |
dc009d92 EB |
88 | /* |
89 | * Note smp_send_stop is the usual smp shutdown function, which | |
90 | * unfortunately means it may not be hardened to work in a panic | |
91 | * situation. | |
92 | */ | |
1da177e4 | 93 | smp_send_stop(); |
1da177e4 | 94 | |
e041c683 | 95 | atomic_notifier_call_chain(&panic_notifier_list, 0, buf); |
1da177e4 LT |
96 | |
97 | if (!panic_blink) | |
98 | panic_blink = no_blink; | |
99 | ||
dc009d92 | 100 | if (panic_timeout > 0) { |
1da177e4 LT |
101 | /* |
102 | * Delay timeout seconds before rebooting the machine. | |
103 | * We can't use the "normal" timers since we just panicked.. | |
104 | */ | |
105 | printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); | |
106 | for (i = 0; i < panic_timeout*1000; ) { | |
107 | touch_nmi_watchdog(); | |
108 | i += panic_blink(i); | |
109 | mdelay(1); | |
110 | i++; | |
111 | } | |
2f048ea8 EB |
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) |
c277e63f | 127 | disabled_wait(caller); |
1da177e4 LT |
128 | #endif |
129 | local_irq_enable(); | |
130 | for (i = 0;;) { | |
c22db941 | 131 | touch_softlockup_watchdog(); |
1da177e4 LT |
132 | i += panic_blink(i); |
133 | mdelay(1); | |
134 | i++; | |
135 | } | |
ffd71da4 | 136 | bust_spinlocks(0); |
1da177e4 LT |
137 | } |
138 | ||
139 | EXPORT_SYMBOL(panic); | |
140 | ||
c277e63f | 141 | |
25ddbb18 AK |
142 | struct tnt { |
143 | u8 bit; | |
144 | char true; | |
145 | char false; | |
146 | }; | |
147 | ||
148 | static const struct tnt tnts[] = { | |
149 | { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, | |
150 | { TAINT_FORCED_MODULE, 'F', ' ' }, | |
151 | { TAINT_UNSAFE_SMP, 'S', ' ' }, | |
152 | { TAINT_FORCED_RMMOD, 'R', ' ' }, | |
153 | { TAINT_MACHINE_CHECK, 'M', ' ' }, | |
154 | { TAINT_BAD_PAGE, 'B', ' ' }, | |
155 | { TAINT_USER, 'U', ' ' }, | |
156 | { TAINT_DIE, 'D', ' ' }, | |
157 | { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, | |
158 | { TAINT_WARN, 'W', ' ' }, | |
26e9a397 | 159 | { TAINT_CRAP, 'C', ' ' }, |
25ddbb18 AK |
160 | }; |
161 | ||
1da177e4 LT |
162 | /** |
163 | * print_tainted - return a string to represent the kernel taint state. | |
164 | * | |
165 | * 'P' - Proprietary module has been loaded. | |
166 | * 'F' - Module has been forcibly loaded. | |
167 | * 'S' - SMP with CPUs not designed for SMP. | |
168 | * 'R' - User forced a module unload. | |
9aa5e993 | 169 | * 'M' - System experienced a machine check exception. |
1da177e4 | 170 | * 'B' - System has hit bad_page. |
34f5a398 | 171 | * 'U' - Userspace-defined naughtiness. |
a8005992 | 172 | * 'D' - Kernel has oopsed before |
95b570c9 NH |
173 | * 'A' - ACPI table overridden. |
174 | * 'W' - Taint on warning. | |
061b1bd3 | 175 | * 'C' - modules from drivers/staging are loaded. |
1da177e4 LT |
176 | * |
177 | * The string is overwritten by the next call to print_taint(). | |
178 | */ | |
1da177e4 LT |
179 | const char *print_tainted(void) |
180 | { | |
25ddbb18 AK |
181 | static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; |
182 | ||
183 | if (tainted_mask) { | |
184 | char *s; | |
185 | int i; | |
186 | ||
187 | s = buf + sprintf(buf, "Tainted: "); | |
188 | for (i = 0; i < ARRAY_SIZE(tnts); i++) { | |
189 | const struct tnt *t = &tnts[i]; | |
190 | *s++ = test_bit(t->bit, &tainted_mask) ? | |
191 | t->true : t->false; | |
192 | } | |
193 | *s = 0; | |
194 | } else | |
1da177e4 LT |
195 | snprintf(buf, sizeof(buf), "Not tainted"); |
196 | return(buf); | |
197 | } | |
198 | ||
25ddbb18 | 199 | int test_taint(unsigned flag) |
1da177e4 | 200 | { |
25ddbb18 AK |
201 | return test_bit(flag, &tainted_mask); |
202 | } | |
203 | EXPORT_SYMBOL(test_taint); | |
204 | ||
205 | unsigned long get_taint(void) | |
206 | { | |
207 | return tainted_mask; | |
1da177e4 | 208 | } |
dd287796 | 209 | |
1da177e4 | 210 | void add_taint(unsigned flag) |
dd287796 | 211 | { |
068c4579 | 212 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
25ddbb18 | 213 | set_bit(flag, &tainted_mask); |
dd287796 | 214 | } |
1da177e4 | 215 | EXPORT_SYMBOL(add_taint); |
dd287796 AM |
216 | |
217 | static void spin_msec(int msecs) | |
218 | { | |
219 | int i; | |
220 | ||
221 | for (i = 0; i < msecs; i++) { | |
222 | touch_nmi_watchdog(); | |
223 | mdelay(1); | |
224 | } | |
225 | } | |
226 | ||
227 | /* | |
228 | * It just happens that oops_enter() and oops_exit() are identically | |
229 | * implemented... | |
230 | */ | |
231 | static void do_oops_enter_exit(void) | |
232 | { | |
233 | unsigned long flags; | |
234 | static int spin_counter; | |
235 | ||
236 | if (!pause_on_oops) | |
237 | return; | |
238 | ||
239 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
240 | if (pause_on_oops_flag == 0) { | |
241 | /* This CPU may now print the oops message */ | |
242 | pause_on_oops_flag = 1; | |
243 | } else { | |
244 | /* We need to stall this CPU */ | |
245 | if (!spin_counter) { | |
246 | /* This CPU gets to do the counting */ | |
247 | spin_counter = pause_on_oops; | |
248 | do { | |
249 | spin_unlock(&pause_on_oops_lock); | |
250 | spin_msec(MSEC_PER_SEC); | |
251 | spin_lock(&pause_on_oops_lock); | |
252 | } while (--spin_counter); | |
253 | pause_on_oops_flag = 0; | |
254 | } else { | |
255 | /* This CPU waits for a different one */ | |
256 | while (spin_counter) { | |
257 | spin_unlock(&pause_on_oops_lock); | |
258 | spin_msec(1); | |
259 | spin_lock(&pause_on_oops_lock); | |
260 | } | |
261 | } | |
262 | } | |
263 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
264 | } | |
265 | ||
266 | /* | |
267 | * Return true if the calling CPU is allowed to print oops-related info. This | |
268 | * is a bit racy.. | |
269 | */ | |
270 | int oops_may_print(void) | |
271 | { | |
272 | return pause_on_oops_flag == 0; | |
273 | } | |
274 | ||
275 | /* | |
276 | * Called when the architecture enters its oops handler, before it prints | |
277 | * anything. If this is the first CPU to oops, and it's oopsing the first time | |
278 | * then let it proceed. | |
279 | * | |
280 | * This is all enabled by the pause_on_oops kernel boot option. We do all this | |
281 | * to ensure that oopses don't scroll off the screen. It has the side-effect | |
282 | * of preventing later-oopsing CPUs from mucking up the display, too. | |
283 | * | |
284 | * It turns out that the CPU which is allowed to print ends up pausing for the | |
285 | * right duration, whereas all the other CPUs pause for twice as long: once in | |
286 | * oops_enter(), once in oops_exit(). | |
287 | */ | |
288 | void oops_enter(void) | |
289 | { | |
2c16e9c8 | 290 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
dd287796 AM |
291 | do_oops_enter_exit(); |
292 | } | |
293 | ||
2c3b20e9 AV |
294 | /* |
295 | * 64-bit random ID for oopses: | |
296 | */ | |
297 | static u64 oops_id; | |
298 | ||
299 | static int init_oops_id(void) | |
300 | { | |
301 | if (!oops_id) | |
302 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
d6624f99 AV |
303 | else |
304 | oops_id++; | |
2c3b20e9 AV |
305 | |
306 | return 0; | |
307 | } | |
308 | late_initcall(init_oops_id); | |
309 | ||
71c33911 AV |
310 | static void print_oops_end_marker(void) |
311 | { | |
312 | init_oops_id(); | |
313 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
314 | (unsigned long long)oops_id); | |
315 | } | |
316 | ||
dd287796 AM |
317 | /* |
318 | * Called when the architecture exits its oops handler, after printing | |
319 | * everything. | |
320 | */ | |
321 | void oops_exit(void) | |
322 | { | |
323 | do_oops_enter_exit(); | |
71c33911 | 324 | print_oops_end_marker(); |
dd287796 | 325 | } |
3162f751 | 326 | |
79b4cc5e | 327 | #ifdef WANT_WARN_ON_SLOWPATH |
a8f18b90 AV |
328 | void warn_slowpath(const char *file, int line, const char *fmt, ...) |
329 | { | |
330 | va_list args; | |
331 | char function[KSYM_SYMBOL_LEN]; | |
332 | unsigned long caller = (unsigned long)__builtin_return_address(0); | |
bd89bb29 AV |
333 | const char *board; |
334 | ||
a8f18b90 AV |
335 | sprint_symbol(function, caller); |
336 | ||
337 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
338 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, | |
339 | line, function); | |
bd89bb29 AV |
340 | board = dmi_get_system_info(DMI_PRODUCT_NAME); |
341 | if (board) | |
342 | printk(KERN_WARNING "Hardware name: %s\n", board); | |
74853dba AV |
343 | |
344 | if (fmt) { | |
345 | va_start(args, fmt); | |
346 | vprintk(fmt, args); | |
347 | va_end(args); | |
348 | } | |
a8f18b90 AV |
349 | |
350 | print_modules(); | |
351 | dump_stack(); | |
352 | print_oops_end_marker(); | |
353 | add_taint(TAINT_WARN); | |
354 | } | |
355 | EXPORT_SYMBOL(warn_slowpath); | |
79b4cc5e AV |
356 | #endif |
357 | ||
3162f751 | 358 | #ifdef CONFIG_CC_STACKPROTECTOR |
54371a43 | 359 | |
3162f751 AV |
360 | /* |
361 | * Called when gcc's -fstack-protector feature is used, and | |
362 | * gcc detects corruption of the on-stack canary value | |
363 | */ | |
364 | void __stack_chk_fail(void) | |
365 | { | |
517a92c4 IM |
366 | panic("stack-protector: Kernel stack is corrupted in: %p\n", |
367 | __builtin_return_address(0)); | |
3162f751 AV |
368 | } |
369 | EXPORT_SYMBOL(__stack_chk_fail); | |
54371a43 | 370 | |
3162f751 | 371 | #endif |
f44dd164 RR |
372 | |
373 | core_param(panic, panic_timeout, int, 0644); | |
374 | core_param(pause_on_oops, pause_on_oops, int, 0644); |