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
  22 int panic_timeout;
  23 int panic_on_oops;
  24 int tainted;
  25
  26 struct notifier_block *panic_notifier_list;
  27
  28 static int __init panic_setup(char *str)
  29 {
  30         panic_timeout = simple_strtoul(str, NULL, 0);
  31         return 1;
  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 perform cleanups. Functions in the panic
  40  *      notifier list are called after the filesystem cache is flushed (when possible).
  41  *
  42  *      This function never returns.
  43  */
  44
  45 NORET_TYPE void panic(const char * fmt, ...)
  46 {
  47         static char buf[1024];
  48         va_list args;
  49 #if defined(CONFIG_ARCH_S390)
  50         unsigned long caller = (unsigned long) __builtin_return_address(0);
  51 #endif
  52
  53         bust_spinlocks(1);
  54         va_start(args, fmt);
  55         vsnprintf(buf, sizeof(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         bust_spinlocks(0);
  65
  66 #ifdef CONFIG_SMP
  67         smp_send_stop();
  68 #endif
  69
  70        notifier_call_chain(&panic_notifier_list, 0, buf);
  71
  72         if (panic_timeout > 0)
  73         {
  74                 /*
  75                  * Delay timeout seconds before rebooting the machine.
  76                  * We can't use the "normal" timers since we just panicked..
  77                  */
  78                 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
  79                 mdelay(panic_timeout*1000);
  80                 /*
  81                  *      Should we run the reboot notifier. For the moment Im
  82                  *      choosing not too. It might crash, be corrupt or do
  83                  *      more harm than good for other reasons.
  84                  */
  85                 machine_restart(NULL);
  86         }
  87 #ifdef __sparc__
  88         {
  89                 extern int stop_a_enabled;
  90                 /* Make sure the user can actually press L1-A */
  91                 stop_a_enabled = 1;
  92                 printk(KERN_EMERG "Press L1-A to return to the boot prom\n");
  93         }
  94 #endif
  95 #if defined(CONFIG_ARCH_S390)
  96         disabled_wait(caller);
  97 #endif
  98         local_irq_enable();
  99         for (;;)
 100                 ;
 101 }
 102
 103 /**
 104  *      print_tainted - return a string to represent the kernel taint state.
 105  *
 106  *  'P' - Proprietary module has been loaded.
 107  *  'F' - Module has been forcibly loaded.
 108  *  'S' - SMP with CPUs not designed for SMP.
 109  *
 110  *      The string is overwritten by the next call to print_taint().
 111  */
 112
 113 const char *print_tainted(void)
 114 {
 115         static char buf[20];
 116         if (tainted) {
 117                 snprintf(buf, sizeof(buf), "Tainted: %c%c%c",
 118                         tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 119                         tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 120                         tainted & TAINT_UNSAFE_SMP ? 'S' : ' ');
 121         }
 122         else
 123                 snprintf(buf, sizeof(buf), "Not tainted");
 124         return(buf);
 125 }