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 LT |
25 | int panic_on_oops; |
26 | int tainted; | |
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 | ||
146 | /** | |
147 | * print_tainted - return a string to represent the kernel taint state. | |
148 | * | |
149 | * 'P' - Proprietary module has been loaded. | |
150 | * 'F' - Module has been forcibly loaded. | |
151 | * 'S' - SMP with CPUs not designed for SMP. | |
152 | * 'R' - User forced a module unload. | |
9aa5e993 | 153 | * 'M' - System experienced a machine check exception. |
1da177e4 | 154 | * 'B' - System has hit bad_page. |
34f5a398 | 155 | * 'U' - Userspace-defined naughtiness. |
95b570c9 NH |
156 | * 'A' - ACPI table overridden. |
157 | * 'W' - Taint on warning. | |
1da177e4 LT |
158 | * |
159 | * The string is overwritten by the next call to print_taint(). | |
160 | */ | |
c277e63f | 161 | |
1da177e4 LT |
162 | const char *print_tainted(void) |
163 | { | |
164 | static char buf[20]; | |
165 | if (tainted) { | |
95b570c9 | 166 | snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c%c", |
1da177e4 LT |
167 | tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G', |
168 | tainted & TAINT_FORCED_MODULE ? 'F' : ' ', | |
169 | tainted & TAINT_UNSAFE_SMP ? 'S' : ' ', | |
170 | tainted & TAINT_FORCED_RMMOD ? 'R' : ' ', | |
c277e63f | 171 | tainted & TAINT_MACHINE_CHECK ? 'M' : ' ', |
34f5a398 | 172 | tainted & TAINT_BAD_PAGE ? 'B' : ' ', |
bcdcd8e7 | 173 | tainted & TAINT_USER ? 'U' : ' ', |
6ed31e92 | 174 | tainted & TAINT_DIE ? 'D' : ' ', |
95b570c9 NH |
175 | tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ', |
176 | tainted & TAINT_WARN ? 'W' : ' '); | |
1da177e4 LT |
177 | } |
178 | else | |
179 | snprintf(buf, sizeof(buf), "Not tainted"); | |
180 | return(buf); | |
181 | } | |
182 | ||
183 | void add_taint(unsigned flag) | |
184 | { | |
068c4579 | 185 | debug_locks = 0; /* can't trust the integrity of the kernel anymore */ |
1da177e4 LT |
186 | tainted |= flag; |
187 | } | |
188 | EXPORT_SYMBOL(add_taint); | |
dd287796 AM |
189 | |
190 | static int __init pause_on_oops_setup(char *str) | |
191 | { | |
192 | pause_on_oops = simple_strtoul(str, NULL, 0); | |
193 | return 1; | |
194 | } | |
195 | __setup("pause_on_oops=", pause_on_oops_setup); | |
196 | ||
197 | static void spin_msec(int msecs) | |
198 | { | |
199 | int i; | |
200 | ||
201 | for (i = 0; i < msecs; i++) { | |
202 | touch_nmi_watchdog(); | |
203 | mdelay(1); | |
204 | } | |
205 | } | |
206 | ||
207 | /* | |
208 | * It just happens that oops_enter() and oops_exit() are identically | |
209 | * implemented... | |
210 | */ | |
211 | static void do_oops_enter_exit(void) | |
212 | { | |
213 | unsigned long flags; | |
214 | static int spin_counter; | |
215 | ||
216 | if (!pause_on_oops) | |
217 | return; | |
218 | ||
219 | spin_lock_irqsave(&pause_on_oops_lock, flags); | |
220 | if (pause_on_oops_flag == 0) { | |
221 | /* This CPU may now print the oops message */ | |
222 | pause_on_oops_flag = 1; | |
223 | } else { | |
224 | /* We need to stall this CPU */ | |
225 | if (!spin_counter) { | |
226 | /* This CPU gets to do the counting */ | |
227 | spin_counter = pause_on_oops; | |
228 | do { | |
229 | spin_unlock(&pause_on_oops_lock); | |
230 | spin_msec(MSEC_PER_SEC); | |
231 | spin_lock(&pause_on_oops_lock); | |
232 | } while (--spin_counter); | |
233 | pause_on_oops_flag = 0; | |
234 | } else { | |
235 | /* This CPU waits for a different one */ | |
236 | while (spin_counter) { | |
237 | spin_unlock(&pause_on_oops_lock); | |
238 | spin_msec(1); | |
239 | spin_lock(&pause_on_oops_lock); | |
240 | } | |
241 | } | |
242 | } | |
243 | spin_unlock_irqrestore(&pause_on_oops_lock, flags); | |
244 | } | |
245 | ||
246 | /* | |
247 | * Return true if the calling CPU is allowed to print oops-related info. This | |
248 | * is a bit racy.. | |
249 | */ | |
250 | int oops_may_print(void) | |
251 | { | |
252 | return pause_on_oops_flag == 0; | |
253 | } | |
254 | ||
255 | /* | |
256 | * Called when the architecture enters its oops handler, before it prints | |
257 | * anything. If this is the first CPU to oops, and it's oopsing the first time | |
258 | * then let it proceed. | |
259 | * | |
260 | * This is all enabled by the pause_on_oops kernel boot option. We do all this | |
261 | * to ensure that oopses don't scroll off the screen. It has the side-effect | |
262 | * of preventing later-oopsing CPUs from mucking up the display, too. | |
263 | * | |
264 | * It turns out that the CPU which is allowed to print ends up pausing for the | |
265 | * right duration, whereas all the other CPUs pause for twice as long: once in | |
266 | * oops_enter(), once in oops_exit(). | |
267 | */ | |
268 | void oops_enter(void) | |
269 | { | |
2c16e9c8 | 270 | debug_locks_off(); /* can't trust the integrity of the kernel anymore */ |
dd287796 AM |
271 | do_oops_enter_exit(); |
272 | } | |
273 | ||
2c3b20e9 AV |
274 | /* |
275 | * 64-bit random ID for oopses: | |
276 | */ | |
277 | static u64 oops_id; | |
278 | ||
279 | static int init_oops_id(void) | |
280 | { | |
281 | if (!oops_id) | |
282 | get_random_bytes(&oops_id, sizeof(oops_id)); | |
283 | ||
284 | return 0; | |
285 | } | |
286 | late_initcall(init_oops_id); | |
287 | ||
71c33911 AV |
288 | static void print_oops_end_marker(void) |
289 | { | |
290 | init_oops_id(); | |
291 | printk(KERN_WARNING "---[ end trace %016llx ]---\n", | |
292 | (unsigned long long)oops_id); | |
293 | } | |
294 | ||
dd287796 AM |
295 | /* |
296 | * Called when the architecture exits its oops handler, after printing | |
297 | * everything. | |
298 | */ | |
299 | void oops_exit(void) | |
300 | { | |
301 | do_oops_enter_exit(); | |
71c33911 | 302 | print_oops_end_marker(); |
dd287796 | 303 | } |
3162f751 | 304 | |
79b4cc5e AV |
305 | #ifdef WANT_WARN_ON_SLOWPATH |
306 | void warn_on_slowpath(const char *file, int line) | |
307 | { | |
308 | char function[KSYM_SYMBOL_LEN]; | |
309 | unsigned long caller = (unsigned long) __builtin_return_address(0); | |
79b4cc5e | 310 | sprint_symbol(function, caller); |
71c33911 AV |
311 | |
312 | printk(KERN_WARNING "------------[ cut here ]------------\n"); | |
79b4cc5e AV |
313 | printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, |
314 | line, function); | |
71c33911 | 315 | print_modules(); |
79b4cc5e | 316 | dump_stack(); |
71c33911 | 317 | print_oops_end_marker(); |
95b570c9 | 318 | add_taint(TAINT_WARN); |
79b4cc5e AV |
319 | } |
320 | EXPORT_SYMBOL(warn_on_slowpath); | |
321 | #endif | |
322 | ||
3162f751 AV |
323 | #ifdef CONFIG_CC_STACKPROTECTOR |
324 | /* | |
325 | * Called when gcc's -fstack-protector feature is used, and | |
326 | * gcc detects corruption of the on-stack canary value | |
327 | */ | |
328 | void __stack_chk_fail(void) | |
329 | { | |
330 | panic("stack-protector: Kernel stack is corrupted"); | |
331 | } | |
332 | EXPORT_SYMBOL(__stack_chk_fail); | |
333 | #endif |