Merge branch 'hwmon-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
[deliverable/linux.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>
1da177e4 24
1da177e4 25int panic_on_oops;
25ddbb18 26static unsigned long tainted_mask;
dd287796
AM
27static int pause_on_oops;
28static int pause_on_oops_flag;
29static DEFINE_SPINLOCK(pause_on_oops_lock);
1da177e4 30
dd287796 31int panic_timeout;
1da177e4 32
e041c683 33ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
1da177e4
LT
34
35EXPORT_SYMBOL(panic_notifier_list);
36
37static 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
44static long no_blink(long time)
45{
46 return 0;
47}
48
49/* Returns how long it waited in ms */
50long (*panic_blink)(long time);
51EXPORT_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
62NORET_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
144EXPORT_SYMBOL(panic);
145
c277e63f 146
25ddbb18
AK
147struct tnt {
148 u8 bit;
149 char true;
150 char false;
151};
152
153static const struct tnt tnts[] = {
154 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
155 { TAINT_FORCED_MODULE, 'F', ' ' },
156 { TAINT_UNSAFE_SMP, 'S', ' ' },
157 { TAINT_FORCED_RMMOD, 'R', ' ' },
158 { TAINT_MACHINE_CHECK, 'M', ' ' },
159 { TAINT_BAD_PAGE, 'B', ' ' },
160 { TAINT_USER, 'U', ' ' },
161 { TAINT_DIE, 'D', ' ' },
162 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
163 { TAINT_WARN, 'W', ' ' },
164};
165
6d5cd6ef
RD
166/**
167 * print_tainted - return a string to represent the kernel taint state.
168 *
169 * 'P' - Proprietary module has been loaded.
170 * 'F' - Module has been forcibly loaded.
171 * 'S' - SMP with CPUs not designed for SMP.
172 * 'R' - User forced a module unload.
173 * 'M' - System experienced a machine check exception.
174 * 'B' - System has hit bad_page.
175 * 'U' - Userspace-defined naughtiness.
176 * 'A' - ACPI table overridden.
177 * 'W' - Taint on warning.
178 *
179 * The string is overwritten by the next call to print_taint().
180 */
1da177e4
LT
181const 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
AK
201int test_taint(unsigned flag)
202{
203 return test_bit(flag, &tainted_mask);
204}
205EXPORT_SYMBOL(test_taint);
206
207unsigned long get_taint(void)
208{
209 return tainted_mask;
210}
211
1da177e4
LT
212void add_taint(unsigned flag)
213{
068c4579 214 debug_locks = 0; /* can't trust the integrity of the kernel anymore */
25ddbb18 215 set_bit(flag, &tainted_mask);
1da177e4
LT
216}
217EXPORT_SYMBOL(add_taint);
dd287796
AM
218
219static int __init pause_on_oops_setup(char *str)
220{
221 pause_on_oops = simple_strtoul(str, NULL, 0);
222 return 1;
223}
224__setup("pause_on_oops=", pause_on_oops_setup);
225
226static void spin_msec(int msecs)
227{
228 int i;
229
230 for (i = 0; i < msecs; i++) {
231 touch_nmi_watchdog();
232 mdelay(1);
233 }
234}
235
236/*
237 * It just happens that oops_enter() and oops_exit() are identically
238 * implemented...
239 */
240static void do_oops_enter_exit(void)
241{
242 unsigned long flags;
243 static int spin_counter;
244
245 if (!pause_on_oops)
246 return;
247
248 spin_lock_irqsave(&pause_on_oops_lock, flags);
249 if (pause_on_oops_flag == 0) {
250 /* This CPU may now print the oops message */
251 pause_on_oops_flag = 1;
252 } else {
253 /* We need to stall this CPU */
254 if (!spin_counter) {
255 /* This CPU gets to do the counting */
256 spin_counter = pause_on_oops;
257 do {
258 spin_unlock(&pause_on_oops_lock);
259 spin_msec(MSEC_PER_SEC);
260 spin_lock(&pause_on_oops_lock);
261 } while (--spin_counter);
262 pause_on_oops_flag = 0;
263 } else {
264 /* This CPU waits for a different one */
265 while (spin_counter) {
266 spin_unlock(&pause_on_oops_lock);
267 spin_msec(1);
268 spin_lock(&pause_on_oops_lock);
269 }
270 }
271 }
272 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
273}
274
275/*
276 * Return true if the calling CPU is allowed to print oops-related info. This
277 * is a bit racy..
278 */
279int oops_may_print(void)
280{
281 return pause_on_oops_flag == 0;
282}
283
284/*
285 * Called when the architecture enters its oops handler, before it prints
286 * anything. If this is the first CPU to oops, and it's oopsing the first time
287 * then let it proceed.
288 *
289 * This is all enabled by the pause_on_oops kernel boot option. We do all this
290 * to ensure that oopses don't scroll off the screen. It has the side-effect
291 * of preventing later-oopsing CPUs from mucking up the display, too.
292 *
293 * It turns out that the CPU which is allowed to print ends up pausing for the
294 * right duration, whereas all the other CPUs pause for twice as long: once in
295 * oops_enter(), once in oops_exit().
296 */
297void oops_enter(void)
298{
2c16e9c8 299 debug_locks_off(); /* can't trust the integrity of the kernel anymore */
dd287796
AM
300 do_oops_enter_exit();
301}
302
2c3b20e9
AV
303/*
304 * 64-bit random ID for oopses:
305 */
306static u64 oops_id;
307
308static int init_oops_id(void)
309{
310 if (!oops_id)
311 get_random_bytes(&oops_id, sizeof(oops_id));
312
313 return 0;
314}
315late_initcall(init_oops_id);
316
71c33911
AV
317static void print_oops_end_marker(void)
318{
319 init_oops_id();
320 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
321 (unsigned long long)oops_id);
322}
323
dd287796
AM
324/*
325 * Called when the architecture exits its oops handler, after printing
326 * everything.
327 */
328void oops_exit(void)
329{
330 do_oops_enter_exit();
71c33911 331 print_oops_end_marker();
dd287796 332}
3162f751 333
79b4cc5e
AV
334#ifdef WANT_WARN_ON_SLOWPATH
335void warn_on_slowpath(const char *file, int line)
336{
337 char function[KSYM_SYMBOL_LEN];
338 unsigned long caller = (unsigned long) __builtin_return_address(0);
79b4cc5e 339 sprint_symbol(function, caller);
71c33911
AV
340
341 printk(KERN_WARNING "------------[ cut here ]------------\n");
79b4cc5e
AV
342 printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
343 line, function);
71c33911 344 print_modules();
79b4cc5e 345 dump_stack();
71c33911 346 print_oops_end_marker();
95b570c9 347 add_taint(TAINT_WARN);
79b4cc5e
AV
348}
349EXPORT_SYMBOL(warn_on_slowpath);
a8f18b90
AV
350
351
352void warn_slowpath(const char *file, int line, const char *fmt, ...)
353{
354 va_list args;
355 char function[KSYM_SYMBOL_LEN];
356 unsigned long caller = (unsigned long)__builtin_return_address(0);
357 sprint_symbol(function, caller);
358
359 printk(KERN_WARNING "------------[ cut here ]------------\n");
360 printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
361 line, function);
362 va_start(args, fmt);
363 vprintk(fmt, args);
364 va_end(args);
365
366 print_modules();
367 dump_stack();
368 print_oops_end_marker();
369 add_taint(TAINT_WARN);
370}
371EXPORT_SYMBOL(warn_slowpath);
79b4cc5e
AV
372#endif
373
3162f751
AV
374#ifdef CONFIG_CC_STACKPROTECTOR
375/*
376 * Called when gcc's -fstack-protector feature is used, and
377 * gcc detects corruption of the on-stack canary value
378 */
379void __stack_chk_fail(void)
380{
381 panic("stack-protector: Kernel stack is corrupted");
382}
383EXPORT_SYMBOL(__stack_chk_fail);
384#endif
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