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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - kernel/panic.c
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>
25 static int pause_on_oops
;
26 static int pause_on_oops_flag
;
27 static DEFINE_SPINLOCK(pause_on_oops_lock
);
31 ATOMIC_NOTIFIER_HEAD(panic_notifier_list
);
33 EXPORT_SYMBOL(panic_notifier_list
);
35 static int __init
panic_setup(char *str
)
37 panic_timeout
= simple_strtoul(str
, NULL
, 0);
40 __setup("panic=", panic_setup
);
42 static long no_blink(long time
)
47 /* Returns how long it waited in ms */
48 long (*panic_blink
)(long time
);
49 EXPORT_SYMBOL(panic_blink
);
52 * panic - halt the system
53 * @fmt: The text string to print
55 * Display a message, then perform cleanups.
57 * This function never returns.
60 NORET_TYPE
void panic(const char * fmt
, ...)
63 static char buf
[1024];
65 #if defined(CONFIG_S390)
66 unsigned long caller
= (unsigned long) __builtin_return_address(0);
70 * It's possible to come here directly from a panic-assertion and not
71 * have preempt disabled. Some functions called from here want
72 * preempt to be disabled. No point enabling it later though...
78 vsnprintf(buf
, sizeof(buf
), fmt
, args
);
80 printk(KERN_EMERG
"Kernel panic - not syncing: %s\n",buf
);
84 * If we have crashed and we have a crash kernel loaded let it handle
86 * Do we want to call this before we try to display a message?
92 * Note smp_send_stop is the usual smp shutdown function, which
93 * unfortunately means it may not be hardened to work in a panic
99 atomic_notifier_call_chain(&panic_notifier_list
, 0, buf
);
102 panic_blink
= no_blink
;
104 if (panic_timeout
> 0) {
106 * Delay timeout seconds before rebooting the machine.
107 * We can't use the "normal" timers since we just panicked..
109 printk(KERN_EMERG
"Rebooting in %d seconds..",panic_timeout
);
110 for (i
= 0; i
< panic_timeout
*1000; ) {
111 touch_nmi_watchdog();
116 /* This will not be a clean reboot, with everything
117 * shutting down. But if there is a chance of
118 * rebooting the system it will be rebooted.
124 extern int stop_a_enabled
;
125 /* Make sure the user can actually press Stop-A (L1-A) */
127 printk(KERN_EMERG
"Press Stop-A (L1-A) to return to the boot prom\n");
130 #if defined(CONFIG_S390)
131 disabled_wait(caller
);
135 touch_softlockup_watchdog();
142 EXPORT_SYMBOL(panic
);
145 * print_tainted - return a string to represent the kernel taint state.
147 * 'P' - Proprietary module has been loaded.
148 * 'F' - Module has been forcibly loaded.
149 * 'S' - SMP with CPUs not designed for SMP.
150 * 'R' - User forced a module unload.
151 * 'M' - Machine had a machine check experience.
152 * 'B' - System has hit bad_page.
154 * The string is overwritten by the next call to print_taint().
157 const char *print_tainted(void)
161 snprintf(buf
, sizeof(buf
), "Tainted: %c%c%c%c%c%c",
162 tainted
& TAINT_PROPRIETARY_MODULE
? 'P' : 'G',
163 tainted
& TAINT_FORCED_MODULE
? 'F' : ' ',
164 tainted
& TAINT_UNSAFE_SMP
? 'S' : ' ',
165 tainted
& TAINT_FORCED_RMMOD
? 'R' : ' ',
166 tainted
& TAINT_MACHINE_CHECK
? 'M' : ' ',
167 tainted
& TAINT_BAD_PAGE
? 'B' : ' ');
170 snprintf(buf
, sizeof(buf
), "Not tainted");
174 void add_taint(unsigned flag
)
176 debug_locks
= 0; /* can't trust the integrity of the kernel anymore */
179 EXPORT_SYMBOL(add_taint
);
181 static int __init
pause_on_oops_setup(char *str
)
183 pause_on_oops
= simple_strtoul(str
, NULL
, 0);
186 __setup("pause_on_oops=", pause_on_oops_setup
);
188 static void spin_msec(int msecs
)
192 for (i
= 0; i
< msecs
; i
++) {
193 touch_nmi_watchdog();
199 * It just happens that oops_enter() and oops_exit() are identically
202 static void do_oops_enter_exit(void)
205 static int spin_counter
;
210 spin_lock_irqsave(&pause_on_oops_lock
, flags
);
211 if (pause_on_oops_flag
== 0) {
212 /* This CPU may now print the oops message */
213 pause_on_oops_flag
= 1;
215 /* We need to stall this CPU */
217 /* This CPU gets to do the counting */
218 spin_counter
= pause_on_oops
;
220 spin_unlock(&pause_on_oops_lock
);
221 spin_msec(MSEC_PER_SEC
);
222 spin_lock(&pause_on_oops_lock
);
223 } while (--spin_counter
);
224 pause_on_oops_flag
= 0;
226 /* This CPU waits for a different one */
227 while (spin_counter
) {
228 spin_unlock(&pause_on_oops_lock
);
230 spin_lock(&pause_on_oops_lock
);
234 spin_unlock_irqrestore(&pause_on_oops_lock
, flags
);
238 * Return true if the calling CPU is allowed to print oops-related info. This
241 int oops_may_print(void)
243 return pause_on_oops_flag
== 0;
247 * Called when the architecture enters its oops handler, before it prints
248 * anything. If this is the first CPU to oops, and it's oopsing the first time
249 * then let it proceed.
251 * This is all enabled by the pause_on_oops kernel boot option. We do all this
252 * to ensure that oopses don't scroll off the screen. It has the side-effect
253 * of preventing later-oopsing CPUs from mucking up the display, too.
255 * It turns out that the CPU which is allowed to print ends up pausing for the
256 * right duration, whereas all the other CPUs pause for twice as long: once in
257 * oops_enter(), once in oops_exit().
259 void oops_enter(void)
261 debug_locks_off(); /* can't trust the integrity of the kernel anymore */
262 do_oops_enter_exit();
266 * Called when the architecture exits its oops handler, after printing
271 do_oops_enter_exit();
274 #ifdef CONFIG_CC_STACKPROTECTOR
276 * Called when gcc's -fstack-protector feature is used, and
277 * gcc detects corruption of the on-stack canary value
279 void __stack_chk_fail(void)
281 panic("stack-protector: Kernel stack is corrupted");
283 EXPORT_SYMBOL(__stack_chk_fail
);