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/module.h>
  13 #include <linux/sched.h>
  14 #include <linux/delay.h>
  15 #include <linux/reboot.h>
  16 #include <linux/notifier.h>
  17 #include <linux/init.h>
  18 #include <linux/sysrq.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/nmi.h>
  21
  22 asmlinkage void sys_sync(void); /* it's really int */
  23
  24 int panic_timeout;
  25 int panic_on_oops;
  26 int tainted;
  27
  28 EXPORT_SYMBOL(panic_timeout);
  29
  30 struct notifier_block *panic_notifier_list;
  31
  32 EXPORT_SYMBOL(panic_notifier_list);
  33
  34 static int __init panic_setup(char *str)
  35 {
  36         panic_timeout = simple_strtoul(str, NULL, 0);
  37         return 1;
  38 }
  39 __setup("panic=", panic_setup);
  40
  41 /**
  42  *      panic - halt the system
  43  *      @fmt: The text string to print
  44  *
  45  *      Display a message, then perform cleanups. Functions in the panic
  46  *      notifier list are called after the filesystem cache is flushed (when possible).
  47  *
  48  *      This function never returns.
  49  */
  50
  51 NORET_TYPE void panic(const char * fmt, ...)
  52 {
  53         static char buf[1024];
  54         va_list args;
  55 #if defined(CONFIG_ARCH_S390)
  56         unsigned long caller = (unsigned long) __builtin_return_address(0);
  57 #endif
  58
  59         bust_spinlocks(1);
  60         va_start(args, fmt);
  61         vsnprintf(buf, sizeof(buf), fmt, args);
  62         va_end(args);
  63         printk(KERN_EMERG "Kernel panic: %s\n",buf);
  64         if (in_interrupt())
  65                 printk(KERN_EMERG "In interrupt handler - not syncing\n");
  66         else if (!current->pid)
  67                 printk(KERN_EMERG "In idle task - not syncing\n");
  68         else
  69                 sys_sync();
  70         bust_spinlocks(0);
  71
  72 #ifdef CONFIG_SMP
  73         smp_send_stop();
  74 #endif
  75
  76        notifier_call_chain(&panic_notifier_list, 0, buf);
  77
  78         if (panic_timeout > 0)
  79         {
  80                 int i;
  81                 /*
  82                  * Delay timeout seconds before rebooting the machine.
  83                  * We can't use the "normal" timers since we just panicked..
  84                  */
  85                 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
  86                 for (i = 0; i < panic_timeout; i++) {
  87                         touch_nmi_watchdog();
  88                         mdelay(1000);
  89                 }
  90                 /*
  91                  *      Should we run the reboot notifier. For the moment Im
  92                  *      choosing not too. It might crash, be corrupt or do
  93                  *      more harm than good for other reasons.
  94                  */
  95                 machine_restart(NULL);
  96         }
  97 #ifdef __sparc__
  98         {
  99                 extern int stop_a_enabled;
 100                 /* Make sure the user can actually press L1-A */
 101                 stop_a_enabled = 1;
 102                 printk(KERN_EMERG "Press L1-A to return to the boot prom\n");
 103         }
 104 #endif
 105 #if defined(CONFIG_ARCH_S390)
 106         disabled_wait(caller);
 107 #endif
 108         local_irq_enable();
 109         for (;;)
 110                 ;
 111 }
 112
 113 EXPORT_SYMBOL(panic);
 114
 115 /**
 116  *      print_tainted - return a string to represent the kernel taint state.
 117  *
 118  *  'P' - Proprietary module has been loaded.
 119  *  'F' - Module has been forcibly loaded.
 120  *  'S' - SMP with CPUs not designed for SMP.
 121  *
 122  *      The string is overwritten by the next call to print_taint().
 123  */
 124
 125 const char *print_tainted(void)
 126 {
 127         static char buf[20];
 128         if (tainted) {
 129                 snprintf(buf, sizeof(buf), "Tainted: %c%c%c",
 130                         tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 131                         tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 132                         tainted & TAINT_UNSAFE_SMP ? 'S' : ' ');
 133         }
 134         else
 135                 snprintf(buf, sizeof(buf), "Not tainted");
 136         return(buf);
 137 }