Merge branch 'akpm'
[linux-2.6/next.git] / kernel / panic.c
blobd7bb6974efb56b6070a6c9067bd87ba55a7273da
1 /*
2 * linux/kernel/panic.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
7 /*
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
11 #include <linux/debug_locks.h>
12 #include <linux/interrupt.h>
13 #include <linux/kmsg_dump.h>
14 #include <linux/kallsyms.h>
15 #include <linux/notifier.h>
16 #include <linux/module.h>
17 #include <linux/random.h>
18 #include <linux/reboot.h>
19 #include <linux/delay.h>
20 #include <linux/kexec.h>
21 #include <linux/sched.h>
22 #include <linux/sysrq.h>
23 #include <linux/init.h>
24 #include <linux/nmi.h>
25 #include <linux/dmi.h>
27 #define PANIC_TIMER_STEP 100
28 #define PANIC_BLINK_SPD 18
30 int panic_on_oops;
31 static unsigned long tainted_mask;
32 static int pause_on_oops;
33 static int pause_on_oops_flag;
34 static DEFINE_SPINLOCK(pause_on_oops_lock);
36 int panic_timeout;
37 EXPORT_SYMBOL_GPL(panic_timeout);
39 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
41 EXPORT_SYMBOL(panic_notifier_list);
43 static long no_blink(int state)
45 return 0;
48 /* Returns how long it waited in ms */
49 long (*panic_blink)(int state);
50 EXPORT_SYMBOL(panic_blink);
52 /**
53 * panic - halt the system
54 * @fmt: The text string to print
56 * Display a message, then perform cleanups.
58 * This function never returns.
60 NORET_TYPE void panic(const char * fmt, ...)
62 static char buf[1024];
63 va_list args;
64 long i, i_next = 0;
65 int state = 0;
68 * It's possible to come here directly from a panic-assertion and
69 * not have preempt disabled. Some functions called from here want
70 * preempt to be disabled. No point enabling it later though...
72 preempt_disable();
74 console_verbose();
75 bust_spinlocks(1);
76 va_start(args, fmt);
77 vsnprintf(buf, sizeof(buf), fmt, args);
78 va_end(args);
79 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
80 #ifdef CONFIG_DEBUG_BUGVERBOSE
81 dump_stack();
82 #endif
85 * If we have crashed and we have a crash kernel loaded let it handle
86 * everything else.
87 * Do we want to call this before we try to display a message?
89 crash_kexec(NULL);
91 kmsg_dump(KMSG_DUMP_PANIC);
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.
98 smp_send_stop();
100 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
102 bust_spinlocks(0);
104 if (!panic_blink)
105 panic_blink = no_blink;
107 if (panic_timeout > 0) {
109 * Delay timeout seconds before rebooting the machine.
110 * We can't use the "normal" timers since we just panicked.
112 printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
114 for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
115 touch_nmi_watchdog();
116 if (i >= i_next) {
117 i += panic_blink(state ^= 1);
118 i_next = i + 3600 / PANIC_BLINK_SPD;
120 mdelay(PANIC_TIMER_STEP);
123 if (panic_timeout != 0) {
125 * This will not be a clean reboot, with everything
126 * shutting down. But if there is a chance of
127 * rebooting the system it will be rebooted.
129 emergency_restart();
131 #ifdef __sparc__
133 extern int stop_a_enabled;
134 /* Make sure the user can actually press Stop-A (L1-A) */
135 stop_a_enabled = 1;
136 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
138 #endif
139 #if defined(CONFIG_S390)
141 unsigned long caller;
143 caller = (unsigned long)__builtin_return_address(0);
144 disabled_wait(caller);
146 #endif
147 local_irq_enable();
148 for (i = 0; ; i += PANIC_TIMER_STEP) {
149 touch_softlockup_watchdog();
150 if (i >= i_next) {
151 i += panic_blink(state ^= 1);
152 i_next = i + 3600 / PANIC_BLINK_SPD;
154 mdelay(PANIC_TIMER_STEP);
158 EXPORT_SYMBOL(panic);
161 struct tnt {
162 u8 bit;
163 char true;
164 char false;
167 static const struct tnt tnts[] = {
168 { TAINT_PROPRIETARY_MODULE, 'P', 'G' },
169 { TAINT_FORCED_MODULE, 'F', ' ' },
170 { TAINT_UNSAFE_SMP, 'S', ' ' },
171 { TAINT_FORCED_RMMOD, 'R', ' ' },
172 { TAINT_MACHINE_CHECK, 'M', ' ' },
173 { TAINT_BAD_PAGE, 'B', ' ' },
174 { TAINT_USER, 'U', ' ' },
175 { TAINT_DIE, 'D', ' ' },
176 { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
177 { TAINT_WARN, 'W', ' ' },
178 { TAINT_CRAP, 'C', ' ' },
179 { TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
183 * print_tainted - return a string to represent the kernel taint state.
185 * 'P' - Proprietary module has been loaded.
186 * 'F' - Module has been forcibly loaded.
187 * 'S' - SMP with CPUs not designed for SMP.
188 * 'R' - User forced a module unload.
189 * 'M' - System experienced a machine check exception.
190 * 'B' - System has hit bad_page.
191 * 'U' - Userspace-defined naughtiness.
192 * 'D' - Kernel has oopsed before
193 * 'A' - ACPI table overridden.
194 * 'W' - Taint on warning.
195 * 'C' - modules from drivers/staging are loaded.
196 * 'I' - Working around severe firmware bug.
198 * The string is overwritten by the next call to print_tainted().
200 const char *print_tainted(void)
202 static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
204 if (tainted_mask) {
205 char *s;
206 int i;
208 s = buf + sprintf(buf, "Tainted: ");
209 for (i = 0; i < ARRAY_SIZE(tnts); i++) {
210 const struct tnt *t = &tnts[i];
211 *s++ = test_bit(t->bit, &tainted_mask) ?
212 t->true : t->false;
214 *s = 0;
215 } else
216 snprintf(buf, sizeof(buf), "Not tainted");
218 return buf;
221 int test_taint(unsigned flag)
223 return test_bit(flag, &tainted_mask);
225 EXPORT_SYMBOL(test_taint);
227 unsigned long get_taint(void)
229 return tainted_mask;
232 void add_taint(unsigned flag)
235 * Can't trust the integrity of the kernel anymore.
236 * We don't call directly debug_locks_off() because the issue
237 * is not necessarily serious enough to set oops_in_progress to 1
238 * Also we want to keep up lockdep for staging development and
239 * post-warning case.
241 if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
242 printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
244 set_bit(flag, &tainted_mask);
246 EXPORT_SYMBOL(add_taint);
248 static void spin_msec(int msecs)
250 int i;
252 for (i = 0; i < msecs; i++) {
253 touch_nmi_watchdog();
254 mdelay(1);
259 * It just happens that oops_enter() and oops_exit() are identically
260 * implemented...
262 static void do_oops_enter_exit(void)
264 unsigned long flags;
265 static int spin_counter;
267 if (!pause_on_oops)
268 return;
270 spin_lock_irqsave(&pause_on_oops_lock, flags);
271 if (pause_on_oops_flag == 0) {
272 /* This CPU may now print the oops message */
273 pause_on_oops_flag = 1;
274 } else {
275 /* We need to stall this CPU */
276 if (!spin_counter) {
277 /* This CPU gets to do the counting */
278 spin_counter = pause_on_oops;
279 do {
280 spin_unlock(&pause_on_oops_lock);
281 spin_msec(MSEC_PER_SEC);
282 spin_lock(&pause_on_oops_lock);
283 } while (--spin_counter);
284 pause_on_oops_flag = 0;
285 } else {
286 /* This CPU waits for a different one */
287 while (spin_counter) {
288 spin_unlock(&pause_on_oops_lock);
289 spin_msec(1);
290 spin_lock(&pause_on_oops_lock);
294 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
298 * Return true if the calling CPU is allowed to print oops-related info.
299 * This is a bit racy..
301 int oops_may_print(void)
303 return pause_on_oops_flag == 0;
307 * Called when the architecture enters its oops handler, before it prints
308 * anything. If this is the first CPU to oops, and it's oopsing the first
309 * time then let it proceed.
311 * This is all enabled by the pause_on_oops kernel boot option. We do all
312 * this to ensure that oopses don't scroll off the screen. It has the
313 * side-effect of preventing later-oopsing CPUs from mucking up the display,
314 * too.
316 * It turns out that the CPU which is allowed to print ends up pausing for
317 * the right duration, whereas all the other CPUs pause for twice as long:
318 * once in oops_enter(), once in oops_exit().
320 void oops_enter(void)
322 tracing_off();
323 /* can't trust the integrity of the kernel anymore: */
324 debug_locks_off();
325 do_oops_enter_exit();
329 * 64-bit random ID for oopses:
331 static u64 oops_id;
333 static int init_oops_id(void)
335 if (!oops_id)
336 get_random_bytes(&oops_id, sizeof(oops_id));
337 else
338 oops_id++;
340 return 0;
342 late_initcall(init_oops_id);
344 void print_oops_end_marker(void)
346 init_oops_id();
347 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
348 (unsigned long long)oops_id);
352 * Called when the architecture exits its oops handler, after printing
353 * everything.
355 void oops_exit(void)
357 do_oops_enter_exit();
358 print_oops_end_marker();
359 kmsg_dump(KMSG_DUMP_OOPS);
362 #ifdef WANT_WARN_ON_SLOWPATH
363 struct slowpath_args {
364 const char *fmt;
365 va_list args;
368 static void warn_slowpath_common(const char *file, int line, void *caller,
369 unsigned taint, struct slowpath_args *args)
371 const char *board;
373 printk(KERN_WARNING "------------[ cut here ]------------\n");
374 printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
375 board = dmi_get_system_info(DMI_PRODUCT_NAME);
376 if (board)
377 printk(KERN_WARNING "Hardware name: %s\n", board);
379 if (args)
380 vprintk(args->fmt, args->args);
382 print_modules();
383 dump_stack();
384 print_oops_end_marker();
385 add_taint(taint);
388 void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
390 struct slowpath_args args;
392 args.fmt = fmt;
393 va_start(args.args, fmt);
394 warn_slowpath_common(file, line, __builtin_return_address(0),
395 TAINT_WARN, &args);
396 va_end(args.args);
398 EXPORT_SYMBOL(warn_slowpath_fmt);
400 void warn_slowpath_fmt_taint(const char *file, int line,
401 unsigned taint, const char *fmt, ...)
403 struct slowpath_args args;
405 args.fmt = fmt;
406 va_start(args.args, fmt);
407 warn_slowpath_common(file, line, __builtin_return_address(0),
408 taint, &args);
409 va_end(args.args);
411 EXPORT_SYMBOL(warn_slowpath_fmt_taint);
413 void warn_slowpath_null(const char *file, int line)
415 warn_slowpath_common(file, line, __builtin_return_address(0),
416 TAINT_WARN, NULL);
418 EXPORT_SYMBOL(warn_slowpath_null);
419 #endif
421 #ifdef CONFIG_CC_STACKPROTECTOR
424 * Called when gcc's -fstack-protector feature is used, and
425 * gcc detects corruption of the on-stack canary value
427 void __stack_chk_fail(void)
429 panic("stack-protector: Kernel stack is corrupted in: %p\n",
430 __builtin_return_address(0));
432 EXPORT_SYMBOL(__stack_chk_fail);
434 #endif
436 core_param(panic, panic_timeout, int, 0644);
437 core_param(pause_on_oops, pause_on_oops, int, 0644);
439 static int __init oops_setup(char *s)
441 if (!s)
442 return -EINVAL;
443 if (!strcmp(s, "panic"))
444 panic_on_oops = 1;
445 return 0;
447 early_param("oops", oops_setup);