kernel/panic.c

   1 /*
   2  *  linux/kernel/panic.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  * This function is used through-out the kernel (including mm and fs)
   9  * to indicate a major problem.
  10  */
  11 #include <linux/config.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
  20 asmlinkage void sys_sync(void); /* it's really int */
  21 extern void unblank_console(void);
  22
  23 int panic_timeout;
  24
  25 struct notifier_block *panic_notifier_list = NULL;
  26
  27 static int __init panic_setup(char *str)
  28 {
  29         panic_timeout = simple_strtoul(str, NULL, 0);
  30         return 1;
  31 }
  32
  33 __setup("panic=", panic_setup);
  34
  35 /**
  36  *      panic - halt the system
  37  *      @fmt: The text string to print
  38  *
  39  *      Display a message, then unblank the console and perform
  40  *      cleanups. Functions in the panic notifier list are called
  41  *      after the filesystem cache is flushed (when possible).
  42  *
  43  *      This function never returns.
  44  */
  45
  46 NORET_TYPE void panic(const char * fmt, ...)
  47 {
  48         static char buf[1024];
  49         va_list args;
  50 #if defined(CONFIG_ARCH_S390)
  51         unsigned long caller = (unsigned long) __builtin_return_address(0);
  52 #endif
  53
  54         va_start(args, fmt);
  55         vsprintf(buf, fmt, args);
  56         va_end(args);
  57         printk(KERN_EMERG "Kernel panic: %s\n",buf);
  58         if (in_interrupt())
  59                 printk(KERN_EMERG "In interrupt handler - not syncing\n");
  60         else if (!current->pid)
  61                 printk(KERN_EMERG "In idle task - not syncing\n");
  62         else
  63                 sys_sync();
  64
  65         unblank_console();
  66
  67 #ifdef CONFIG_SMP
  68         smp_send_stop();
  69 #endif
  70
  71         notifier_call_chain(&panic_notifier_list, 0, NULL);
  72
  73         if (panic_timeout > 0)
  74         {
  75                 /*
  76                  * Delay timeout seconds before rebooting the machine.
  77                  * We can't use the "normal" timers since we just panicked..
  78                  */
  79                 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
  80                 mdelay(panic_timeout*1000);
  81                 /*
  82                  *      Should we run the reboot notifier. For the moment Im
  83                  *      choosing not too. It might crash, be corrupt or do
  84                  *      more harm than good for other reasons.
  85                  */
  86                 machine_restart(NULL);
  87         }
  88 #ifdef __sparc__
  89         {
  90                 extern int stop_a_enabled;
  91                 /* Make sure the user can actually press L1-A */
  92                 stop_a_enabled = 1;
  93                 printk("Press L1-A to return to the boot prom\n");
  94         }
  95 #endif
  96 #if defined(CONFIG_ARCH_S390)
  97         disabled_wait(caller);
  98 #endif
  99         sti();
 100         for(;;) {
 101                 CHECK_EMERGENCY_SYNC
 102         }
 103 }