4 * Copyright (C) 1991, 1992 Linus Torvalds
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/console.h>
27 #define PANIC_TIMER_STEP 100
28 #define PANIC_BLINK_SPD 18
30 /* Machine specific panic information string */
31 char *mach_panic_string
;
33 int panic_on_oops
= CONFIG_PANIC_ON_OOPS_VALUE
;
34 static unsigned long tainted_mask
;
35 static int pause_on_oops
;
36 static int pause_on_oops_flag
;
37 static DEFINE_SPINLOCK(pause_on_oops_lock
);
39 #ifndef CONFIG_PANIC_TIMEOUT
40 #define CONFIG_PANIC_TIMEOUT 0
42 int panic_timeout
= CONFIG_PANIC_TIMEOUT
;
43 EXPORT_SYMBOL_GPL(panic_timeout
);
45 ATOMIC_NOTIFIER_HEAD(panic_notifier_list
);
47 EXPORT_SYMBOL(panic_notifier_list
);
49 static long no_blink(int state
)
54 /* Returns how long it waited in ms */
55 long (*panic_blink
)(int state
);
56 EXPORT_SYMBOL(panic_blink
);
59 * Stop ourself in panic -- architecture code may override this
61 void __weak
panic_smp_self_stop(void)
68 * panic - halt the system
69 * @fmt: The text string to print
71 * Display a message, then perform cleanups.
73 * This function never returns.
75 void panic(const char *fmt
, ...)
77 static DEFINE_SPINLOCK(panic_lock
);
78 static char buf
[1024];
84 * Disable local interrupts. This will prevent panic_smp_self_stop
85 * from deadlocking the first cpu that invokes the panic, since
86 * there is nothing to prevent an interrupt handler (that runs
87 * after the panic_lock is acquired) from invoking panic again.
92 * It's possible to come here directly from a panic-assertion and
93 * not have preempt disabled. Some functions called from here want
94 * preempt to be disabled. No point enabling it later though...
96 * Only one CPU is allowed to execute the panic code from here. For
97 * multiple parallel invocations of panic, all other CPUs either
98 * stop themself or will wait until they are stopped by the 1st CPU
99 * with smp_send_stop().
101 if (!spin_trylock(&panic_lock
))
102 panic_smp_self_stop();
107 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
109 printk(KERN_EMERG
"Kernel panic - not syncing: %s\n",buf
);
110 #ifdef CONFIG_DEBUG_BUGVERBOSE
112 * Avoid nested stack-dumping if a panic occurs during oops processing
114 if (!test_taint(TAINT_DIE
) && oops_in_progress
<= 1)
119 * If we have crashed and we have a crash kernel loaded let it handle
121 * Do we want to call this before we try to display a message?
126 * Note smp_send_stop is the usual smp shutdown function, which
127 * unfortunately means it may not be hardened to work in a panic
132 kmsg_dump(KMSG_DUMP_PANIC
);
134 atomic_notifier_call_chain(&panic_notifier_list
, 0, buf
);
138 console_flush_on_panic();
141 panic_blink
= no_blink
;
143 if (panic_timeout
> 0) {
145 * Delay timeout seconds before rebooting the machine.
146 * We can't use the "normal" timers since we just panicked.
148 printk(KERN_EMERG
"Rebooting in %d seconds..", panic_timeout
);
150 for (i
= 0; i
< panic_timeout
* 1000; i
+= PANIC_TIMER_STEP
) {
151 touch_nmi_watchdog();
153 i
+= panic_blink(state
^= 1);
154 i_next
= i
+ 3600 / PANIC_BLINK_SPD
;
156 mdelay(PANIC_TIMER_STEP
);
159 if (panic_timeout
!= 0) {
161 * This will not be a clean reboot, with everything
162 * shutting down. But if there is a chance of
163 * rebooting the system it will be rebooted.
169 extern int stop_a_enabled
;
170 /* Make sure the user can actually press Stop-A (L1-A) */
172 printk(KERN_EMERG
"Press Stop-A (L1-A) to return to the boot prom\n");
175 #if defined(CONFIG_S390)
177 unsigned long caller
;
179 caller
= (unsigned long)__builtin_return_address(0);
180 disabled_wait(caller
);
184 for (i
= 0; ; i
+= PANIC_TIMER_STEP
) {
185 touch_softlockup_watchdog();
187 i
+= panic_blink(state
^= 1);
188 i_next
= i
+ 3600 / PANIC_BLINK_SPD
;
190 mdelay(PANIC_TIMER_STEP
);
194 EXPORT_SYMBOL(panic
);
203 static const struct tnt tnts
[] = {
204 { TAINT_PROPRIETARY_MODULE
, 'P', 'G' },
205 { TAINT_FORCED_MODULE
, 'F', ' ' },
206 { TAINT_UNSAFE_SMP
, 'S', ' ' },
207 { TAINT_FORCED_RMMOD
, 'R', ' ' },
208 { TAINT_MACHINE_CHECK
, 'M', ' ' },
209 { TAINT_BAD_PAGE
, 'B', ' ' },
210 { TAINT_USER
, 'U', ' ' },
211 { TAINT_DIE
, 'D', ' ' },
212 { TAINT_OVERRIDDEN_ACPI_TABLE
, 'A', ' ' },
213 { TAINT_WARN
, 'W', ' ' },
214 { TAINT_CRAP
, 'C', ' ' },
215 { TAINT_FIRMWARE_WORKAROUND
, 'I', ' ' },
216 { TAINT_OOT_MODULE
, 'O', ' ' },
220 * print_tainted - return a string to represent the kernel taint state.
222 * 'P' - Proprietary module has been loaded.
223 * 'F' - Module has been forcibly loaded.
224 * 'S' - SMP with CPUs not designed for SMP.
225 * 'R' - User forced a module unload.
226 * 'M' - System experienced a machine check exception.
227 * 'B' - System has hit bad_page.
228 * 'U' - Userspace-defined naughtiness.
229 * 'D' - Kernel has oopsed before
230 * 'A' - ACPI table overridden.
231 * 'W' - Taint on warning.
232 * 'C' - modules from drivers/staging are loaded.
233 * 'I' - Working around severe firmware bug.
234 * 'O' - Out-of-tree module has been loaded.
236 * The string is overwritten by the next call to print_tainted().
238 const char *print_tainted(void)
240 static char buf
[ARRAY_SIZE(tnts
) + sizeof("Tainted: ") + 1];
246 s
= buf
+ sprintf(buf
, "Tainted: ");
247 for (i
= 0; i
< ARRAY_SIZE(tnts
); i
++) {
248 const struct tnt
*t
= &tnts
[i
];
249 *s
++ = test_bit(t
->bit
, &tainted_mask
) ?
254 snprintf(buf
, sizeof(buf
), "Not tainted");
259 int test_taint(unsigned flag
)
261 return test_bit(flag
, &tainted_mask
);
263 EXPORT_SYMBOL(test_taint
);
265 unsigned long get_taint(void)
271 * add_taint: add a taint flag if not already set.
272 * @flag: one of the TAINT_* constants.
273 * @lockdep_ok: whether lock debugging is still OK.
275 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
276 * some notewortht-but-not-corrupting cases, it can be set to true.
278 void add_taint(unsigned flag
, enum lockdep_ok lockdep_ok
)
280 if (lockdep_ok
== LOCKDEP_NOW_UNRELIABLE
&& __debug_locks_off())
282 "Disabling lock debugging due to kernel taint\n");
284 set_bit(flag
, &tainted_mask
);
286 EXPORT_SYMBOL(add_taint
);
288 static void spin_msec(int msecs
)
292 for (i
= 0; i
< msecs
; i
++) {
293 touch_nmi_watchdog();
299 * It just happens that oops_enter() and oops_exit() are identically
302 static void do_oops_enter_exit(void)
305 static int spin_counter
;
310 spin_lock_irqsave(&pause_on_oops_lock
, flags
);
311 if (pause_on_oops_flag
== 0) {
312 /* This CPU may now print the oops message */
313 pause_on_oops_flag
= 1;
315 /* We need to stall this CPU */
317 /* This CPU gets to do the counting */
318 spin_counter
= pause_on_oops
;
320 spin_unlock(&pause_on_oops_lock
);
321 spin_msec(MSEC_PER_SEC
);
322 spin_lock(&pause_on_oops_lock
);
323 } while (--spin_counter
);
324 pause_on_oops_flag
= 0;
326 /* This CPU waits for a different one */
327 while (spin_counter
) {
328 spin_unlock(&pause_on_oops_lock
);
330 spin_lock(&pause_on_oops_lock
);
334 spin_unlock_irqrestore(&pause_on_oops_lock
, flags
);
338 * Return true if the calling CPU is allowed to print oops-related info.
339 * This is a bit racy..
341 int oops_may_print(void)
343 return pause_on_oops_flag
== 0;
347 * Called when the architecture enters its oops handler, before it prints
348 * anything. If this is the first CPU to oops, and it's oopsing the first
349 * time then let it proceed.
351 * This is all enabled by the pause_on_oops kernel boot option. We do all
352 * this to ensure that oopses don't scroll off the screen. It has the
353 * side-effect of preventing later-oopsing CPUs from mucking up the display,
356 * It turns out that the CPU which is allowed to print ends up pausing for
357 * the right duration, whereas all the other CPUs pause for twice as long:
358 * once in oops_enter(), once in oops_exit().
360 void oops_enter(void)
363 /* can't trust the integrity of the kernel anymore: */
365 do_oops_enter_exit();
369 * 64-bit random ID for oopses:
373 static int init_oops_id(void)
376 get_random_bytes(&oops_id
, sizeof(oops_id
));
382 late_initcall(init_oops_id
);
384 void print_oops_end_marker(void)
388 if (mach_panic_string
)
389 printk(KERN_WARNING
"Board Information: %s\n",
392 printk(KERN_WARNING
"---[ end trace %016llx ]---\n",
393 (unsigned long long)oops_id
);
397 * Called when the architecture exits its oops handler, after printing
402 do_oops_enter_exit();
403 print_oops_end_marker();
404 kmsg_dump(KMSG_DUMP_OOPS
);
407 #ifdef WANT_WARN_ON_SLOWPATH
408 struct slowpath_args
{
413 static void warn_slowpath_common(const char *file
, int line
, void *caller
,
414 unsigned taint
, struct slowpath_args
*args
)
416 printk(KERN_WARNING
"------------[ cut here ]------------\n");
417 printk(KERN_WARNING
"WARNING: at %s:%d %pS()\n", file
, line
, caller
);
420 vprintk(args
->fmt
, args
->args
);
424 print_oops_end_marker();
425 /* Just a warning, don't kill lockdep. */
426 add_taint(taint
, LOCKDEP_STILL_OK
);
429 void warn_slowpath_fmt(const char *file
, int line
, const char *fmt
, ...)
431 struct slowpath_args args
;
434 va_start(args
.args
, fmt
);
435 warn_slowpath_common(file
, line
, __builtin_return_address(0),
439 EXPORT_SYMBOL(warn_slowpath_fmt
);
441 void warn_slowpath_fmt_taint(const char *file
, int line
,
442 unsigned taint
, const char *fmt
, ...)
444 struct slowpath_args args
;
447 va_start(args
.args
, fmt
);
448 warn_slowpath_common(file
, line
, __builtin_return_address(0),
452 EXPORT_SYMBOL(warn_slowpath_fmt_taint
);
454 void warn_slowpath_null(const char *file
, int line
)
456 warn_slowpath_common(file
, line
, __builtin_return_address(0),
459 EXPORT_SYMBOL(warn_slowpath_null
);
462 #ifdef CONFIG_CC_STACKPROTECTOR
465 * Called when gcc's -fstack-protector feature is used, and
466 * gcc detects corruption of the on-stack canary value
468 void __stack_chk_fail(void)
471 panic("stack-protector: Kernel stack is corrupted in: %p\n",
472 __builtin_return_address(0));
475 printk(KERN_ERR
"stack-protector: Kernel stack is corrupted in: %p\n",
476 __builtin_return_address(0));
478 EXPORT_SYMBOL(__stack_chk_fail
);
482 core_param(panic
, panic_timeout
, int, 0644);
483 core_param(pause_on_oops
, pause_on_oops
, int, 0644);
485 static int __init
oops_setup(char *s
)
489 if (!strcmp(s
, "panic"))
493 early_param("oops", oops_setup
);