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>
26 #define PANIC_TIMER_STEP 100
27 #define PANIC_BLINK_SPD 18
29 /* Machine specific panic information string */
30 char *mach_panic_string
;
32 int panic_on_oops
= CONFIG_PANIC_ON_OOPS_VALUE
;
33 static unsigned long tainted_mask
;
34 static int pause_on_oops
;
35 static int pause_on_oops_flag
;
36 static DEFINE_SPINLOCK(pause_on_oops_lock
);
38 #ifndef CONFIG_PANIC_TIMEOUT
39 #define CONFIG_PANIC_TIMEOUT 0
41 int panic_timeout
= CONFIG_PANIC_TIMEOUT
;
42 EXPORT_SYMBOL_GPL(panic_timeout
);
44 ATOMIC_NOTIFIER_HEAD(panic_notifier_list
);
46 EXPORT_SYMBOL(panic_notifier_list
);
48 static long no_blink(int state
)
53 /* Returns how long it waited in ms */
54 long (*panic_blink
)(int state
);
55 EXPORT_SYMBOL(panic_blink
);
58 * Stop ourself in panic -- architecture code may override this
60 void __weak
panic_smp_self_stop(void)
67 * panic - halt the system
68 * @fmt: The text string to print
70 * Display a message, then perform cleanups.
72 * This function never returns.
74 void panic(const char *fmt
, ...)
76 static DEFINE_SPINLOCK(panic_lock
);
77 static char buf
[1024];
83 * Disable local interrupts. This will prevent panic_smp_self_stop
84 * from deadlocking the first cpu that invokes the panic, since
85 * there is nothing to prevent an interrupt handler (that runs
86 * after the panic_lock is acquired) from invoking panic again.
91 * It's possible to come here directly from a panic-assertion and
92 * not have preempt disabled. Some functions called from here want
93 * preempt to be disabled. No point enabling it later though...
95 * Only one CPU is allowed to execute the panic code from here. For
96 * multiple parallel invocations of panic, all other CPUs either
97 * stop themself or will wait until they are stopped by the 1st CPU
98 * with smp_send_stop().
100 if (!spin_trylock(&panic_lock
))
101 panic_smp_self_stop();
106 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
108 printk(KERN_EMERG
"Kernel panic - not syncing: %s\n",buf
);
109 #ifdef CONFIG_DEBUG_BUGVERBOSE
111 * Avoid nested stack-dumping if a panic occurs during oops processing
113 if (!test_taint(TAINT_DIE
) && oops_in_progress
<= 1)
118 * If we have crashed and we have a crash kernel loaded let it handle
120 * Do we want to call this before we try to display a message?
125 * Note smp_send_stop is the usual smp shutdown function, which
126 * unfortunately means it may not be hardened to work in a panic
131 kmsg_dump(KMSG_DUMP_PANIC
);
133 atomic_notifier_call_chain(&panic_notifier_list
, 0, buf
);
138 panic_blink
= no_blink
;
140 if (panic_timeout
> 0) {
142 * Delay timeout seconds before rebooting the machine.
143 * We can't use the "normal" timers since we just panicked.
145 printk(KERN_EMERG
"Rebooting in %d seconds..", panic_timeout
);
147 for (i
= 0; i
< panic_timeout
* 1000; i
+= PANIC_TIMER_STEP
) {
148 touch_nmi_watchdog();
150 i
+= panic_blink(state
^= 1);
151 i_next
= i
+ 3600 / PANIC_BLINK_SPD
;
153 mdelay(PANIC_TIMER_STEP
);
156 if (panic_timeout
!= 0) {
158 * This will not be a clean reboot, with everything
159 * shutting down. But if there is a chance of
160 * rebooting the system it will be rebooted.
166 extern int stop_a_enabled
;
167 /* Make sure the user can actually press Stop-A (L1-A) */
169 printk(KERN_EMERG
"Press Stop-A (L1-A) to return to the boot prom\n");
172 #if defined(CONFIG_S390)
174 unsigned long caller
;
176 caller
= (unsigned long)__builtin_return_address(0);
177 disabled_wait(caller
);
181 for (i
= 0; ; i
+= PANIC_TIMER_STEP
) {
182 touch_softlockup_watchdog();
184 i
+= panic_blink(state
^= 1);
185 i_next
= i
+ 3600 / PANIC_BLINK_SPD
;
187 mdelay(PANIC_TIMER_STEP
);
191 EXPORT_SYMBOL(panic
);
200 static const struct tnt tnts
[] = {
201 { TAINT_PROPRIETARY_MODULE
, 'P', 'G' },
202 { TAINT_FORCED_MODULE
, 'F', ' ' },
203 { TAINT_UNSAFE_SMP
, 'S', ' ' },
204 { TAINT_FORCED_RMMOD
, 'R', ' ' },
205 { TAINT_MACHINE_CHECK
, 'M', ' ' },
206 { TAINT_BAD_PAGE
, 'B', ' ' },
207 { TAINT_USER
, 'U', ' ' },
208 { TAINT_DIE
, 'D', ' ' },
209 { TAINT_OVERRIDDEN_ACPI_TABLE
, 'A', ' ' },
210 { TAINT_WARN
, 'W', ' ' },
211 { TAINT_CRAP
, 'C', ' ' },
212 { TAINT_FIRMWARE_WORKAROUND
, 'I', ' ' },
213 { TAINT_OOT_MODULE
, 'O', ' ' },
217 * print_tainted - return a string to represent the kernel taint state.
219 * 'P' - Proprietary module has been loaded.
220 * 'F' - Module has been forcibly loaded.
221 * 'S' - SMP with CPUs not designed for SMP.
222 * 'R' - User forced a module unload.
223 * 'M' - System experienced a machine check exception.
224 * 'B' - System has hit bad_page.
225 * 'U' - Userspace-defined naughtiness.
226 * 'D' - Kernel has oopsed before
227 * 'A' - ACPI table overridden.
228 * 'W' - Taint on warning.
229 * 'C' - modules from drivers/staging are loaded.
230 * 'I' - Working around severe firmware bug.
231 * 'O' - Out-of-tree module has been loaded.
233 * The string is overwritten by the next call to print_tainted().
235 const char *print_tainted(void)
237 static char buf
[ARRAY_SIZE(tnts
) + sizeof("Tainted: ") + 1];
243 s
= buf
+ sprintf(buf
, "Tainted: ");
244 for (i
= 0; i
< ARRAY_SIZE(tnts
); i
++) {
245 const struct tnt
*t
= &tnts
[i
];
246 *s
++ = test_bit(t
->bit
, &tainted_mask
) ?
251 snprintf(buf
, sizeof(buf
), "Not tainted");
256 int test_taint(unsigned flag
)
258 return test_bit(flag
, &tainted_mask
);
260 EXPORT_SYMBOL(test_taint
);
262 unsigned long get_taint(void)
268 * add_taint: add a taint flag if not already set.
269 * @flag: one of the TAINT_* constants.
270 * @lockdep_ok: whether lock debugging is still OK.
272 * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
273 * some notewortht-but-not-corrupting cases, it can be set to true.
275 void add_taint(unsigned flag
, enum lockdep_ok lockdep_ok
)
277 if (lockdep_ok
== LOCKDEP_NOW_UNRELIABLE
&& __debug_locks_off())
279 "Disabling lock debugging due to kernel taint\n");
281 set_bit(flag
, &tainted_mask
);
283 EXPORT_SYMBOL(add_taint
);
285 static void spin_msec(int msecs
)
289 for (i
= 0; i
< msecs
; i
++) {
290 touch_nmi_watchdog();
296 * It just happens that oops_enter() and oops_exit() are identically
299 static void do_oops_enter_exit(void)
302 static int spin_counter
;
307 spin_lock_irqsave(&pause_on_oops_lock
, flags
);
308 if (pause_on_oops_flag
== 0) {
309 /* This CPU may now print the oops message */
310 pause_on_oops_flag
= 1;
312 /* We need to stall this CPU */
314 /* This CPU gets to do the counting */
315 spin_counter
= pause_on_oops
;
317 spin_unlock(&pause_on_oops_lock
);
318 spin_msec(MSEC_PER_SEC
);
319 spin_lock(&pause_on_oops_lock
);
320 } while (--spin_counter
);
321 pause_on_oops_flag
= 0;
323 /* This CPU waits for a different one */
324 while (spin_counter
) {
325 spin_unlock(&pause_on_oops_lock
);
327 spin_lock(&pause_on_oops_lock
);
331 spin_unlock_irqrestore(&pause_on_oops_lock
, flags
);
335 * Return true if the calling CPU is allowed to print oops-related info.
336 * This is a bit racy..
338 int oops_may_print(void)
340 return pause_on_oops_flag
== 0;
344 * Called when the architecture enters its oops handler, before it prints
345 * anything. If this is the first CPU to oops, and it's oopsing the first
346 * time then let it proceed.
348 * This is all enabled by the pause_on_oops kernel boot option. We do all
349 * this to ensure that oopses don't scroll off the screen. It has the
350 * side-effect of preventing later-oopsing CPUs from mucking up the display,
353 * It turns out that the CPU which is allowed to print ends up pausing for
354 * the right duration, whereas all the other CPUs pause for twice as long:
355 * once in oops_enter(), once in oops_exit().
357 void oops_enter(void)
360 /* can't trust the integrity of the kernel anymore: */
362 do_oops_enter_exit();
366 * 64-bit random ID for oopses:
370 static int init_oops_id(void)
373 get_random_bytes(&oops_id
, sizeof(oops_id
));
379 late_initcall(init_oops_id
);
381 void print_oops_end_marker(void)
385 if (mach_panic_string
)
386 printk(KERN_WARNING
"Board Information: %s\n",
389 printk(KERN_WARNING
"---[ end trace %016llx ]---\n",
390 (unsigned long long)oops_id
);
394 * Called when the architecture exits its oops handler, after printing
399 do_oops_enter_exit();
400 print_oops_end_marker();
401 kmsg_dump(KMSG_DUMP_OOPS
);
404 #ifdef WANT_WARN_ON_SLOWPATH
405 struct slowpath_args
{
410 static void warn_slowpath_common(const char *file
, int line
, void *caller
,
411 unsigned taint
, struct slowpath_args
*args
)
413 printk(KERN_WARNING
"------------[ cut here ]------------\n");
414 printk(KERN_WARNING
"WARNING: at %s:%d %pS()\n", file
, line
, caller
);
417 vprintk(args
->fmt
, args
->args
);
421 print_oops_end_marker();
422 /* Just a warning, don't kill lockdep. */
423 add_taint(taint
, LOCKDEP_STILL_OK
);
426 void warn_slowpath_fmt(const char *file
, int line
, const char *fmt
, ...)
428 struct slowpath_args args
;
431 va_start(args
.args
, fmt
);
432 warn_slowpath_common(file
, line
, __builtin_return_address(0),
436 EXPORT_SYMBOL(warn_slowpath_fmt
);
438 void warn_slowpath_fmt_taint(const char *file
, int line
,
439 unsigned taint
, const char *fmt
, ...)
441 struct slowpath_args args
;
444 va_start(args
.args
, fmt
);
445 warn_slowpath_common(file
, line
, __builtin_return_address(0),
449 EXPORT_SYMBOL(warn_slowpath_fmt_taint
);
451 void warn_slowpath_null(const char *file
, int line
)
453 warn_slowpath_common(file
, line
, __builtin_return_address(0),
456 EXPORT_SYMBOL(warn_slowpath_null
);
459 #ifdef CONFIG_CC_STACKPROTECTOR
462 * Called when gcc's -fstack-protector feature is used, and
463 * gcc detects corruption of the on-stack canary value
465 void __stack_chk_fail(void)
468 panic("stack-protector: Kernel stack is corrupted in: %p\n",
469 __builtin_return_address(0));
472 printk(KERN_ERR
"stack-protector: Kernel stack is corrupted in: %p\n",
473 __builtin_return_address(0));
475 EXPORT_SYMBOL(__stack_chk_fail
);
479 core_param(panic
, panic_timeout
, int, 0644);
480 core_param(pause_on_oops
, pause_on_oops
, int, 0644);
482 static int __init
oops_setup(char *s
)
486 if (!strcmp(s
, "panic"))
490 early_param("oops", oops_setup
);