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/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>
20 #include <linux/kexec.h>
21 #include <linux/debug_locks.h>
22 #include <linux/random.h>
23 #include <linux/kallsyms.h>
27 static int pause_on_oops
;
28 static int pause_on_oops_flag
;
29 static DEFINE_SPINLOCK(pause_on_oops_lock
);
33 ATOMIC_NOTIFIER_HEAD(panic_notifier_list
);
35 EXPORT_SYMBOL(panic_notifier_list
);
37 static int __init
panic_setup(char *str
)
39 panic_timeout
= simple_strtoul(str
, NULL
, 0);
42 __setup("panic=", panic_setup
);
44 static long no_blink(long time
)
49 /* Returns how long it waited in ms */
50 long (*panic_blink
)(long time
);
51 EXPORT_SYMBOL(panic_blink
);
54 * panic - halt the system
55 * @fmt: The text string to print
57 * Display a message, then perform cleanups.
59 * This function never returns.
62 NORET_TYPE
void panic(const char * fmt
, ...)
65 static char buf
[1024];
67 #if defined(CONFIG_S390)
68 unsigned long caller
= (unsigned long) __builtin_return_address(0);
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...
80 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
82 printk(KERN_EMERG
"Kernel panic - not syncing: %s\n",buf
);
86 * If we have crashed and we have a crash kernel loaded let it handle
88 * Do we want to call this before we try to display a message?
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
101 atomic_notifier_call_chain(&panic_notifier_list
, 0, buf
);
104 panic_blink
= no_blink
;
106 if (panic_timeout
> 0) {
108 * Delay timeout seconds before rebooting the machine.
109 * We can't use the "normal" timers since we just panicked..
111 printk(KERN_EMERG
"Rebooting in %d seconds..",panic_timeout
);
112 for (i
= 0; i
< panic_timeout
*1000; ) {
113 touch_nmi_watchdog();
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.
126 extern int stop_a_enabled
;
127 /* Make sure the user can actually press Stop-A (L1-A) */
129 printk(KERN_EMERG
"Press Stop-A (L1-A) to return to the boot prom\n");
132 #if defined(CONFIG_S390)
133 disabled_wait(caller
);
137 touch_softlockup_watchdog();
144 EXPORT_SYMBOL(panic
);
147 * print_tainted - return a string to represent the kernel taint state.
149 * 'P' - Proprietary module has been loaded.
150 * 'F' - Module has been forcibly loaded.
151 * 'S' - SMP with CPUs not designed for SMP.
152 * 'R' - User forced a module unload.
153 * 'M' - System experienced a machine check exception.
154 * 'B' - System has hit bad_page.
155 * 'U' - Userspace-defined naughtiness.
157 * The string is overwritten by the next call to print_taint().
160 const char *print_tainted(void)
164 snprintf(buf
, sizeof(buf
), "Tainted: %c%c%c%c%c%c%c%c%c",
165 tainted
& TAINT_PROPRIETARY_MODULE
? 'P' : 'G',
166 tainted
& TAINT_FORCED_MODULE
? 'F' : ' ',
167 tainted
& TAINT_UNSAFE_SMP
? 'S' : ' ',
168 tainted
& TAINT_FORCED_RMMOD
? 'R' : ' ',
169 tainted
& TAINT_MACHINE_CHECK
? 'M' : ' ',
170 tainted
& TAINT_BAD_PAGE
? 'B' : ' ',
171 tainted
& TAINT_USER
? 'U' : ' ',
172 tainted
& TAINT_DIE
? 'D' : ' ',
173 tainted
& TAINT_OVERRIDDEN_ACPI_TABLE
? 'A' : ' ');
176 snprintf(buf
, sizeof(buf
), "Not tainted");
180 void add_taint(unsigned flag
)
182 debug_locks
= 0; /* can't trust the integrity of the kernel anymore */
185 EXPORT_SYMBOL(add_taint
);
187 static int __init
pause_on_oops_setup(char *str
)
189 pause_on_oops
= simple_strtoul(str
, NULL
, 0);
192 __setup("pause_on_oops=", pause_on_oops_setup
);
194 static void spin_msec(int msecs
)
198 for (i
= 0; i
< msecs
; i
++) {
199 touch_nmi_watchdog();
205 * It just happens that oops_enter() and oops_exit() are identically
208 static void do_oops_enter_exit(void)
211 static int spin_counter
;
216 spin_lock_irqsave(&pause_on_oops_lock
, flags
);
217 if (pause_on_oops_flag
== 0) {
218 /* This CPU may now print the oops message */
219 pause_on_oops_flag
= 1;
221 /* We need to stall this CPU */
223 /* This CPU gets to do the counting */
224 spin_counter
= pause_on_oops
;
226 spin_unlock(&pause_on_oops_lock
);
227 spin_msec(MSEC_PER_SEC
);
228 spin_lock(&pause_on_oops_lock
);
229 } while (--spin_counter
);
230 pause_on_oops_flag
= 0;
232 /* This CPU waits for a different one */
233 while (spin_counter
) {
234 spin_unlock(&pause_on_oops_lock
);
236 spin_lock(&pause_on_oops_lock
);
240 spin_unlock_irqrestore(&pause_on_oops_lock
, flags
);
244 * Return true if the calling CPU is allowed to print oops-related info. This
247 int oops_may_print(void)
249 return pause_on_oops_flag
== 0;
253 * Called when the architecture enters its oops handler, before it prints
254 * anything. If this is the first CPU to oops, and it's oopsing the first time
255 * then let it proceed.
257 * This is all enabled by the pause_on_oops kernel boot option. We do all this
258 * to ensure that oopses don't scroll off the screen. It has the side-effect
259 * of preventing later-oopsing CPUs from mucking up the display, too.
261 * It turns out that the CPU which is allowed to print ends up pausing for the
262 * right duration, whereas all the other CPUs pause for twice as long: once in
263 * oops_enter(), once in oops_exit().
265 void oops_enter(void)
267 debug_locks_off(); /* can't trust the integrity of the kernel anymore */
268 do_oops_enter_exit();
272 * 64-bit random ID for oopses:
276 static int init_oops_id(void)
279 get_random_bytes(&oops_id
, sizeof(oops_id
));
283 late_initcall(init_oops_id
);
285 static void print_oops_end_marker(void)
288 printk(KERN_WARNING
"---[ end trace %016llx ]---\n",
289 (unsigned long long)oops_id
);
293 * Called when the architecture exits its oops handler, after printing
298 do_oops_enter_exit();
299 print_oops_end_marker();
302 #ifdef WANT_WARN_ON_SLOWPATH
303 void warn_on_slowpath(const char *file
, int line
)
305 char function
[KSYM_SYMBOL_LEN
];
306 unsigned long caller
= (unsigned long) __builtin_return_address(0);
307 sprint_symbol(function
, caller
);
309 printk(KERN_WARNING
"------------[ cut here ]------------\n");
310 printk(KERN_WARNING
"WARNING: at %s:%d %s()\n", file
,
314 print_oops_end_marker();
316 EXPORT_SYMBOL(warn_on_slowpath
);
319 #ifdef CONFIG_CC_STACKPROTECTOR
321 * Called when gcc's -fstack-protector feature is used, and
322 * gcc detects corruption of the on-stack canary value
324 void __stack_chk_fail(void)
326 panic("stack-protector: Kernel stack is corrupted");
328 EXPORT_SYMBOL(__stack_chk_fail
);