/* * linux/kernel/panic.c * * Copyright (C) 1991, 1992 Linus Torvalds *//* * This function is used through-out the kernel (including mm and fs) * to indicate a major problem. */#include <linux/module.h>#include <linux/sched.h>#include <linux/delay.h>#include <linux/reboot.h>#include <linux/notifier.h>#include <linux/init.h>#include <linux/sysrq.h>#include <linux/interrupt.h>#include <linux/nmi.h>#include <linux/kexec.h>#include <linux/debug_locks.h>int panic_on_oops;int tainted;static int pause_on_oops;static int pause_on_oops_flag;static DEFINE_SPINLOCK(pause_on_oops_lock);int panic_timeout;ATOMIC_NOTIFIER_HEAD(panic_notifier_list);EXPORT_SYMBOL(panic_notifier_list);static int __init panic_setup(char *str){ panic_timeout = simple_strtoul(str, NULL, 0); return 1;}__setup("panic=", panic_setup);static long no_blink(long time){ return 0;}/* Returns how long it waited in ms */long (*panic_blink)(long time);EXPORT_SYMBOL(panic_blink);/** * panic - halt the system * @fmt: The text string to print * * Display a message, then perform cleanups. * * This function never returns. */NORET_TYPE void panic(const char * fmt, ...){ long i; static char buf[1024]; va_list args;#if defined(CONFIG_S390) unsigned long caller = (unsigned long) __builtin_return_address(0);#endif /* * It's possible to come here directly from a panic-assertion and not * have preempt disabled. Some functions called from here want * preempt to be disabled. No point enabling it later though... */ preempt_disable(); bust_spinlocks(1); va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); bust_spinlocks(0); /* * If we have crashed and we have a crash kernel loaded let it handle * everything else. * Do we want to call this before we try to display a message? */ crash_kexec(NULL);#ifdef CONFIG_SMP /* * Note smp_send_stop is the usual smp shutdown function, which * unfortunately means it may not be hardened to work in a panic * situation. */ smp_send_stop();#endif atomic_notifier_call_chain(&panic_notifier_list, 0, buf); if (!panic_blink) panic_blink = no_blink; if (panic_timeout > 0) { /* * Delay timeout seconds before rebooting the machine. * We can't use the "normal" timers since we just panicked.. */ printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout); for (i = 0; i < panic_timeout*1000; ) { touch_nmi_watchdog(); i += panic_blink(i); mdelay(1); i++; } /* This will not be a clean reboot, with everything * shutting down. But if there is a chance of * rebooting the system it will be rebooted. */ emergency_restart(); }#ifdef __sparc__ { extern int stop_a_enabled; /* Make sure the user can actually press Stop-A (L1-A) */ stop_a_enabled = 1; printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); }#endif#if defined(CONFIG_S390) disabled_wait(caller);#endif local_irq_enable(); for (i = 0;;) { touch_softlockup_watchdog(); i += panic_blink(i); mdelay(1); i++; }}EXPORT_SYMBOL(panic);/** * print_tainted - return a string to represent the kernel taint state. * * 'P' - Proprietary module has been loaded. * 'F' - Module has been forcibly loaded. * 'S' - SMP with CPUs not designed for SMP. * 'R' - User forced a module unload. * 'M' - Machine had a machine check experience. * 'B' - System has hit bad_page. * * The string is overwritten by the next call to print_taint(). */const char *print_tainted(void){ static char buf[20]; if (tainted) { snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c", tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G', tainted & TAINT_FORCED_MODULE ? 'F' : ' ', tainted & TAINT_UNSAFE_SMP ? 'S' : ' ', tainted & TAINT_FORCED_RMMOD ? 'R' : ' ', tainted & TAINT_MACHINE_CHECK ? 'M' : ' ', tainted & TAINT_BAD_PAGE ? 'B' : ' '); } else snprintf(buf, sizeof(buf), "Not tainted"); return(buf);}void add_taint(unsigned flag){ debug_locks = 0; /* can't trust the integrity of the kernel anymore */ tainted |= flag;}EXPORT_SYMBOL(add_taint);static int __init pause_on_oops_setup(char *str){ pause_on_oops = simple_strtoul(str, NULL, 0); return 1;}__setup("pause_on_oops=", pause_on_oops_setup);static void spin_msec(int msecs){ int i; for (i = 0; i < msecs; i++) { touch_nmi_watchdog(); mdelay(1); }}/* * It just happens that oops_enter() and oops_exit() are identically * implemented... */static void do_oops_enter_exit(void){ unsigned long flags; static int spin_counter; if (!pause_on_oops) return; spin_lock_irqsave(&pause_on_oops_lock, flags); if (pause_on_oops_flag == 0) { /* This CPU may now print the oops message */ pause_on_oops_flag = 1; } else { /* We need to stall this CPU */ if (!spin_counter) { /* This CPU gets to do the counting */ spin_counter = pause_on_oops; do { spin_unlock(&pause_on_oops_lock); spin_msec(MSEC_PER_SEC); spin_lock(&pause_on_oops_lock); } while (--spin_counter); pause_on_oops_flag = 0; } else { /* This CPU waits for a different one */ while (spin_counter) { spin_unlock(&pause_on_oops_lock); spin_msec(1); spin_lock(&pause_on_oops_lock); } } } spin_unlock_irqrestore(&pause_on_oops_lock, flags);}/* * Return true if the calling CPU is allowed to print oops-related info. This * is a bit racy.. */int oops_may_print(void){ return pause_on_oops_flag == 0;}/* * Called when the architecture enters its oops handler, before it prints * anything. If this is the first CPU to oops, and it's oopsing the first time * then let it proceed. * * This is all enabled by the pause_on_oops kernel boot option. We do all this * to ensure that oopses don't scroll off the screen. It has the side-effect * of preventing later-oopsing CPUs from mucking up the display, too. * * It turns out that the CPU which is allowed to print ends up pausing for the * right duration, whereas all the other CPUs pause for twice as long: once in * oops_enter(), once in oops_exit(). */void oops_enter(void){ debug_locks_off(); /* can't trust the integrity of the kernel anymore */ do_oops_enter_exit();}/* * Called when the architecture exits its oops handler, after printing * everything. */void oops_exit(void){ do_oops_enter_exit();}
/*
* linux/kernel/panic.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* This function is used through-out the kernel (including mm and fs)
* to indicate a major problem.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/sysrq.h>
#include <linux/interrupt.h>
#include <linux/nmi.h>
#include <linux/kexec.h>
#include <linux/debug_locks.h>
int panic_on_oops;
int tainted;
static int pause_on_oops;
static int pause_on_oops_flag;
static DEFINE_SPINLOCK(pause_on_oops_lock);
int panic_timeout;
ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
EXPORT_SYMBOL(panic_notifier_list);
static int __init panic_setup(char *str)
{
panic_timeout = simple_strtoul(str, NULL, 0);
return 1;
}
__setup("panic=", panic_setup);
static long no_blink(long time)
{
return 0;
}
/* Returns how long it waited in ms */
long (*panic_blink)(long time);
EXPORT_SYMBOL(panic_blink);
/**
* panic - halt the system
* @fmt: The text string to print
*
* Display a message, then perform cleanups.
*
* This function never returns.
*/
NORET_TYPE void panic(const char * fmt, ...)
{
long i;
static char buf[1024];
va_list args;
#if defined(CONFIG_S390)
unsigned long caller = (unsigned long) __builtin_return_address(0);
#endif
/*
* It's possible to come here directly from a panic-assertion and not
* have preempt disabled. Some functions called from here want
* preempt to be disabled. No point enabling it later though...
*/
preempt_disable();
bust_spinlocks(1);
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
bust_spinlocks(0);
/*
* If we have crashed and we have a crash kernel loaded let it handle
* everything else.
* Do we want to call this before we try to display a message?
*/
crash_kexec(NULL);
#ifdef CONFIG_SMP
/*
* Note smp_send_stop is the usual smp shutdown function, which
* unfortunately means it may not be hardened to work in a panic
* situation.
*/
smp_send_stop();
#endif
atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
if (!panic_blink)
panic_blink = no_blink;
if (panic_timeout > 0) {
/*
* Delay timeout seconds before rebooting the machine.
* We can't use the "normal" timers since we just panicked..
*/
printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
for (i = 0; i < panic_timeout*1000; ) {
touch_nmi_watchdog();
i += panic_blink(i);
mdelay(1);
i++;
}
/* This will not be a clean reboot, with everything
* shutting down. But if there is a chance of
* rebooting the system it will be rebooted.
*/
emergency_restart();
}
#ifdef __sparc__
{
extern int stop_a_enabled;
/* Make sure the user can actually press Stop-A (L1-A) */
stop_a_enabled = 1;
printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
}
#endif
#if defined(CONFIG_S390)
disabled_wait(caller);
#endif
local_irq_enable();
for (i = 0;;) {
touch_softlockup_watchdog();
i += panic_blink(i);
mdelay(1);
i++;
}
}
EXPORT_SYMBOL(panic);
/**
* print_tainted - return a string to represent the kernel taint state.
*
* 'P' - Proprietary module has been loaded.
* 'F' - Module has been forcibly loaded.
* 'S' - SMP with CPUs not designed for SMP.
* 'R' - User forced a module unload.
* 'M' - Machine had a machine check experience.
* 'B' - System has hit bad_page.
*
* The string is overwritten by the next call to print_taint().
*/
const char *print_tainted(void)
{
static char buf[20];
if (tainted) {
snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c",
tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
tainted & TAINT_BAD_PAGE ? 'B' : ' ');
}
else
snprintf(buf, sizeof(buf), "Not tainted");
return(buf);
}
void add_taint(unsigned flag)
{
debug_locks = 0; /* can't trust the integrity of the kernel anymore */
tainted |= flag;
}
EXPORT_SYMBOL(add_taint);
static int __init pause_on_oops_setup(char *str)
{
pause_on_oops = simple_strtoul(str, NULL, 0);
return 1;
}
__setup("pause_on_oops=", pause_on_oops_setup);
static void spin_msec(int msecs)
{
int i;
for (i = 0; i < msecs; i++) {
touch_nmi_watchdog();
mdelay(1);
}
}
/*
* It just happens that oops_enter() and oops_exit() are identically
* implemented...
*/
static void do_oops_enter_exit(void)
{
unsigned long flags;
static int spin_counter;
if (!pause_on_oops)
return;
spin_lock_irqsave(&pause_on_oops_lock, flags);
if (pause_on_oops_flag == 0) {
/* This CPU may now print the oops message */
pause_on_oops_flag = 1;
} else {
/* We need to stall this CPU */
if (!spin_counter) {
/* This CPU gets to do the counting */
spin_counter = pause_on_oops;
do {
spin_unlock(&pause_on_oops_lock);
spin_msec(MSEC_PER_SEC);
spin_lock(&pause_on_oops_lock);
} while (--spin_counter);
pause_on_oops_flag = 0;
} else {
/* This CPU waits for a different one */
while (spin_counter) {
spin_unlock(&pause_on_oops_lock);
spin_msec(1);
spin_lock(&pause_on_oops_lock);
}
}
}
spin_unlock_irqrestore(&pause_on_oops_lock, flags);
}
/*
* Return true if the calling CPU is allowed to print oops-related info. This
* is a bit racy..
*/
int oops_may_print(void)
{
return pause_on_oops_flag == 0;
}
/*
* Called when the architecture enters its oops handler, before it prints
* anything. If this is the first CPU to oops, and it's oopsing the first time
* then let it proceed.
*
* This is all enabled by the pause_on_oops kernel boot option. We do all this
* to ensure that oopses don't scroll off the screen. It has the side-effect
* of preventing later-oopsing CPUs from mucking up the display, too.
*
* It turns out that the CPU which is allowed to print ends up pausing for the
* right duration, whereas all the other CPUs pause for twice as long: once in
* oops_enter(), once in oops_exit().
*/
void oops_enter(void)
{
debug_locks_off(); /* can't trust the integrity of the kernel anymore */
do_oops_enter_exit();
}
/*
* Called when the architecture exits its oops handler, after printing
* everything.
*/
void oops_exit(void)
{
do_oops_enter_exit();
}