Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core
[linux-2.6-block.git] / kernel / panic.c
CommitLineData
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 26int panic_on_oops;
25ddbb18 27static unsigned long tainted_mask;
dd287796
AM
28static int pause_on_oops;
29static int pause_on_oops_flag;
30static DEFINE_SPINLOCK(pause_on_oops_lock);
1da177e4 31
dd287796 32int panic_timeout;
1da177e4 33
e041c683 34ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
1da177e4
LT
35
36EXPORT_SYMBOL(panic_notifier_list);
37
1da177e4
LT
38static long no_blink(long time)
39{
40 return 0;
41}
42
43/* Returns how long it waited in ms */
44long (*panic_blink)(long time);
45EXPORT_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
56NORET_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);
77 bust_spinlocks(0);
78
dc009d92
EB
79 /*
80 * If we have crashed and we have a crash kernel loaded let it handle
81 * everything else.
82 * Do we want to call this before we try to display a message?
83 */
6e274d14 84 crash_kexec(NULL);
dc009d92 85
1da177e4 86#ifdef CONFIG_SMP
dc009d92
EB
87 /*
88 * Note smp_send_stop is the usual smp shutdown function, which
89 * unfortunately means it may not be hardened to work in a panic
90 * situation.
91 */
1da177e4
LT
92 smp_send_stop();
93#endif
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 }
136}
137
138EXPORT_SYMBOL(panic);
139
c277e63f 140
25ddbb18
AK
141struct tnt {
142 u8 bit;
143 char true;
144 char false;
145};
146
147static const struct tnt tnts[] = {
148 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
149 { TAINT_FORCED_MODULE, 'F', ' ' },
150 { TAINT_UNSAFE_SMP, 'S', ' ' },
151 { TAINT_FORCED_RMMOD, 'R', ' ' },
152 { TAINT_MACHINE_CHECK, 'M', ' ' },
153 { TAINT_BAD_PAGE, 'B', ' ' },
154 { TAINT_USER, 'U', ' ' },
155 { TAINT_DIE, 'D', ' ' },
156 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
157 { TAINT_WARN, 'W', ' ' },
26e9a397 158 { TAINT_CRAP, 'C', ' ' },
25ddbb18
AK
159};
160
6d5cd6ef
RD
161/**
162 * print_tainted - return a string to represent the kernel taint state.
163 *
164 * 'P' - Proprietary module has been loaded.
165 * 'F' - Module has been forcibly loaded.
166 * 'S' - SMP with CPUs not designed for SMP.
167 * 'R' - User forced a module unload.
168 * 'M' - System experienced a machine check exception.
169 * 'B' - System has hit bad_page.
170 * 'U' - Userspace-defined naughtiness.
a8005992 171 * 'D' - Kernel has oopsed before
6d5cd6ef
RD
172 * 'A' - ACPI table overridden.
173 * 'W' - Taint on warning.
061b1bd3 174 * 'C' - modules from drivers/staging are loaded.
6d5cd6ef
RD
175 *
176 * The string is overwritten by the next call to print_taint().
177 */
1da177e4
LT
178const char *print_tainted(void)
179{
25ddbb18
AK
180 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
181
182 if (tainted_mask) {
183 char *s;
184 int i;
185
186 s = buf + sprintf(buf, "Tainted: ");
187 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
188 const struct tnt *t = &tnts[i];
189 *s++ = test_bit(t->bit, &tainted_mask) ?
190 t->true : t->false;
191 }
192 *s = 0;
193 } else
1da177e4
LT
194 snprintf(buf, sizeof(buf), "Not tainted");
195 return(buf);
196}
197
25ddbb18
AK
198int test_taint(unsigned flag)
199{
200 return test_bit(flag, &tainted_mask);
201}
202EXPORT_SYMBOL(test_taint);
203
204unsigned long get_taint(void)
205{
206 return tainted_mask;
207}
208
1da177e4
LT
209void add_taint(unsigned flag)
210{
068c4579 211 debug_locks = 0; /* can't trust the integrity of the kernel anymore */
25ddbb18 212 set_bit(flag, &tainted_mask);
1da177e4
LT
213}
214EXPORT_SYMBOL(add_taint);
dd287796 215
dd287796
AM
216static void spin_msec(int msecs)
217{
218 int i;
219
220 for (i = 0; i < msecs; i++) {
221 touch_nmi_watchdog();
222 mdelay(1);
223 }
224}
225
226/*
227 * It just happens that oops_enter() and oops_exit() are identically
228 * implemented...
229 */
230static void do_oops_enter_exit(void)
231{
232 unsigned long flags;
233 static int spin_counter;
234
235 if (!pause_on_oops)
236 return;
237
238 spin_lock_irqsave(&pause_on_oops_lock, flags);
239 if (pause_on_oops_flag == 0) {
240 /* This CPU may now print the oops message */
241 pause_on_oops_flag = 1;
242 } else {
243 /* We need to stall this CPU */
244 if (!spin_counter) {
245 /* This CPU gets to do the counting */
246 spin_counter = pause_on_oops;
247 do {
248 spin_unlock(&pause_on_oops_lock);
249 spin_msec(MSEC_PER_SEC);
250 spin_lock(&pause_on_oops_lock);
251 } while (--spin_counter);
252 pause_on_oops_flag = 0;
253 } else {
254 /* This CPU waits for a different one */
255 while (spin_counter) {
256 spin_unlock(&pause_on_oops_lock);
257 spin_msec(1);
258 spin_lock(&pause_on_oops_lock);
259 }
260 }
261 }
262 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
263}
264
265/*
266 * Return true if the calling CPU is allowed to print oops-related info. This
267 * is a bit racy..
268 */
269int oops_may_print(void)
270{
271 return pause_on_oops_flag == 0;
272}
273
274/*
275 * Called when the architecture enters its oops handler, before it prints
276 * anything. If this is the first CPU to oops, and it's oopsing the first time
277 * then let it proceed.
278 *
279 * This is all enabled by the pause_on_oops kernel boot option. We do all this
280 * to ensure that oopses don't scroll off the screen. It has the side-effect
281 * of preventing later-oopsing CPUs from mucking up the display, too.
282 *
283 * It turns out that the CPU which is allowed to print ends up pausing for the
284 * right duration, whereas all the other CPUs pause for twice as long: once in
285 * oops_enter(), once in oops_exit().
286 */
287void oops_enter(void)
288{
2c16e9c8 289 debug_locks_off(); /* can't trust the integrity of the kernel anymore */
dd287796
AM
290 do_oops_enter_exit();
291}
292
2c3b20e9
AV
293/*
294 * 64-bit random ID for oopses:
295 */
296static u64 oops_id;
297
298static int init_oops_id(void)
299{
300 if (!oops_id)
301 get_random_bytes(&oops_id, sizeof(oops_id));
d6624f99
AV
302 else
303 oops_id++;
2c3b20e9
AV
304
305 return 0;
306}
307late_initcall(init_oops_id);
308
71c33911
AV
309static void print_oops_end_marker(void)
310{
311 init_oops_id();
312 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
313 (unsigned long long)oops_id);
314}
315
dd287796
AM
316/*
317 * Called when the architecture exits its oops handler, after printing
318 * everything.
319 */
320void oops_exit(void)
321{
322 do_oops_enter_exit();
71c33911 323 print_oops_end_marker();
dd287796 324}
3162f751 325
79b4cc5e 326#ifdef WANT_WARN_ON_SLOWPATH
a8f18b90
AV
327void warn_slowpath(const char *file, int line, const char *fmt, ...)
328{
329 va_list args;
330 char function[KSYM_SYMBOL_LEN];
331 unsigned long caller = (unsigned long)__builtin_return_address(0);
bd89bb29
AV
332 const char *board;
333
a8f18b90
AV
334 sprint_symbol(function, caller);
335
336 printk(KERN_WARNING "------------[ cut here ]------------\n");
337 printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
338 line, function);
bd89bb29
AV
339 board = dmi_get_system_info(DMI_PRODUCT_NAME);
340 if (board)
341 printk(KERN_WARNING "Hardware name: %s\n", board);
74853dba
AV
342
343 if (fmt) {
344 va_start(args, fmt);
345 vprintk(fmt, args);
346 va_end(args);
347 }
a8f18b90
AV
348
349 print_modules();
350 dump_stack();
351 print_oops_end_marker();
352 add_taint(TAINT_WARN);
353}
354EXPORT_SYMBOL(warn_slowpath);
79b4cc5e
AV
355#endif
356
3162f751
AV
357#ifdef CONFIG_CC_STACKPROTECTOR
358/*
359 * Called when gcc's -fstack-protector feature is used, and
360 * gcc detects corruption of the on-stack canary value
361 */
362void __stack_chk_fail(void)
363{
364 panic("stack-protector: Kernel stack is corrupted");
365}
366EXPORT_SYMBOL(__stack_chk_fail);
367#endif
f44dd164
RR
368
369core_param(panic, panic_timeout, int, 0644);
370core_param(pause_on_oops, pause_on_oops, int, 0644);