/* * 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/debug_locks.h>#include <linux/interrupt.h>#include <linux/kallsyms.h>#include <linux/notifier.h>#include <linux/module.h>#include <linux/random.h>#include <linux/reboot.h>#include <linux/delay.h>#include <linux/kexec.h>#include <linux/sched.h>#include <linux/sysrq.h>#include <linux/init.h>#include <linux/nmi.h>#include <linux/dmi.h> int panic_on_oops;static unsigned long tainted_mask;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 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, ...){ static char buf[1024]; va_list args; long i; /* * 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);#ifdef CONFIG_DEBUG_BUGVERBOSE dump_stack();#endif /* * 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); /* * 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(); 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) { unsigned long caller; caller = (unsigned long)__builtin_return_address(0); disabled_wait(caller); }#endif local_irq_enable(); for (i = 0; ; ) { touch_softlockup_watchdog(); i += panic_blink(i); mdelay(1); i++; } bust_spinlocks(0);} EXPORT_SYMBOL(panic); struct tnt { u8 bit; char true; char false;}; static const struct tnt tnts[] = { { TAINT_PROPRIETARY_MODULE, 'P', 'G' }, { TAINT_FORCED_MODULE, 'F', ' ' }, { TAINT_UNSAFE_SMP, 'S', ' ' }, { TAINT_FORCED_RMMOD, 'R', ' ' }, { TAINT_MACHINE_CHECK, 'M', ' ' }, { TAINT_BAD_PAGE, 'B', ' ' }, { TAINT_USER, 'U', ' ' }, { TAINT_DIE, 'D', ' ' }, { TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' }, { TAINT_WARN, 'W', ' ' }, { TAINT_CRAP, 'C', ' ' },}; /** * 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' - System experienced a machine check exception. * 'B' - System has hit bad_page. * 'U' - Userspace-defined naughtiness. * 'D' - Kernel has oopsed before * 'A' - ACPI table overridden. * 'W' - Taint on warning. * 'C' - modules from drivers/staging are loaded. * * The string is overwritten by the next call to print_taint(). */const char *print_tainted(void){ static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1]; if (tainted_mask) { char *s; int i; s = buf + sprintf(buf, "Tainted: "); for (i = 0; i < ARRAY_SIZE(tnts); i++) { const struct tnt *t = &tnts[i]; *s++ = test_bit(t->bit, &tainted_mask) ? t->true : t->false; } *s = 0; } else snprintf(buf, sizeof(buf), "Not tainted"); return buf;} int test_taint(unsigned flag){ return test_bit(flag, &tainted_mask);}EXPORT_SYMBOL(test_taint); unsigned long get_taint(void){ return tainted_mask;} void add_taint(unsigned flag){ /* * Can't trust the integrity of the kernel anymore. * We don't call directly debug_locks_off() because the issue * is not necessarily serious enough to set oops_in_progress to 1 * Also we want to keep up lockdep for staging development and * post-warning case. */ if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off()) printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n"); set_bit(flag, &tainted_mask);}EXPORT_SYMBOL(add_taint); 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){ /* can't trust the integrity of the kernel anymore: */ debug_locks_off(); do_oops_enter_exit();} /* * 64-bit random ID for oopses: */static u64 oops_id; static int init_oops_id(void){ if (!oops_id) get_random_bytes(&oops_id, sizeof(oops_id)); else oops_id++; return 0;}late_initcall(init_oops_id); static void print_oops_end_marker(void){ init_oops_id(); printk(KERN_WARNING "---[ end trace %016llx ]---\n", (unsigned long long)oops_id);} /* * Called when the architecture exits its oops handler, after printing * everything. */void oops_exit(void){ do_oops_enter_exit(); print_oops_end_marker();} #ifdef WANT_WARN_ON_SLOWPATHvoid warn_slowpath(const char *file, int line, const char *fmt, ...){ va_list args; char function[KSYM_SYMBOL_LEN]; unsigned long caller = (unsigned long)__builtin_return_address(0); const char *board; sprint_symbol(function, caller); printk(KERN_WARNING "------------[ cut here ]------------\n"); printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, line, function); board = dmi_get_system_info(DMI_PRODUCT_NAME); if (board) printk(KERN_WARNING "Hardware name: %s\n", board); if (fmt) { va_start(args, fmt); vprintk(fmt, args); va_end(args); } print_modules(); dump_stack(); print_oops_end_marker(); add_taint(TAINT_WARN);}EXPORT_SYMBOL(warn_slowpath);#endif #ifdef CONFIG_CC_STACKPROTECTOR /* * Called when gcc's -fstack-protector feature is used, and * gcc detects corruption of the on-stack canary value */void __stack_chk_fail(void){ panic("stack-protector: Kernel stack is corrupted in: %p\n", __builtin_return_address(0));}EXPORT_SYMBOL(__stack_chk_fail); #endif core_param(panic, panic_timeout, int, 0644);core_param(pause_on_oops, pause_on_oops, int, 0644);
/*
* 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/debug_locks.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/notifier.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/kexec.h>
#include <linux/sched.h>
#include <linux/sysrq.h>
#include <linux/init.h>
#include <linux/nmi.h>
#include <linux/dmi.h>
int panic_on_oops;
static unsigned long tainted_mask;
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 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, ...)
{
static char buf[1024];
va_list args;
long i;
/*
* 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);
#ifdef CONFIG_DEBUG_BUGVERBOSE
dump_stack();
#endif
/*
* 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);
/*
* 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();
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)
{
unsigned long caller;
caller = (unsigned long)__builtin_return_address(0);
disabled_wait(caller);
}
#endif
local_irq_enable();
for (i = 0; ; ) {
touch_softlockup_watchdog();
i += panic_blink(i);
mdelay(1);
i++;
}
bust_spinlocks(0);
}
EXPORT_SYMBOL(panic);
struct tnt {
u8 bit;
char true;
char false;
};
static const struct tnt tnts[] = {
{ TAINT_PROPRIETARY_MODULE, 'P', 'G' },
{ TAINT_FORCED_MODULE, 'F', ' ' },
{ TAINT_UNSAFE_SMP, 'S', ' ' },
{ TAINT_FORCED_RMMOD, 'R', ' ' },
{ TAINT_MACHINE_CHECK, 'M', ' ' },
{ TAINT_BAD_PAGE, 'B', ' ' },
{ TAINT_USER, 'U', ' ' },
{ TAINT_DIE, 'D', ' ' },
{ TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
{ TAINT_WARN, 'W', ' ' },
{ TAINT_CRAP, 'C', ' ' },
};
/**
* 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' - System experienced a machine check exception.
* 'B' - System has hit bad_page.
* 'U' - Userspace-defined naughtiness.
* 'D' - Kernel has oopsed before
* 'A' - ACPI table overridden.
* 'W' - Taint on warning.
* 'C' - modules from drivers/staging are loaded.
*
* The string is overwritten by the next call to print_taint().
*/
const char *print_tainted(void)
{
static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
if (tainted_mask) {
char *s;
int i;
s = buf + sprintf(buf, "Tainted: ");
for (i = 0; i < ARRAY_SIZE(tnts); i++) {
const struct tnt *t = &tnts[i];
*s++ = test_bit(t->bit, &tainted_mask) ?
t->true : t->false;
}
*s = 0;
} else
snprintf(buf, sizeof(buf), "Not tainted");
return buf;
}
int test_taint(unsigned flag)
{
return test_bit(flag, &tainted_mask);
}
EXPORT_SYMBOL(test_taint);
unsigned long get_taint(void)
{
return tainted_mask;
}
void add_taint(unsigned flag)
{
/*
* Can't trust the integrity of the kernel anymore.
* We don't call directly debug_locks_off() because the issue
* is not necessarily serious enough to set oops_in_progress to 1
* Also we want to keep up lockdep for staging development and
* post-warning case.
*/
if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
set_bit(flag, &tainted_mask);
}
EXPORT_SYMBOL(add_taint);
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)
{
/* can't trust the integrity of the kernel anymore: */
debug_locks_off();
do_oops_enter_exit();
}
/*
* 64-bit random ID for oopses:
*/
static u64 oops_id;
static int init_oops_id(void)
{
if (!oops_id)
get_random_bytes(&oops_id, sizeof(oops_id));
else
oops_id++;
return 0;
}
late_initcall(init_oops_id);
static void print_oops_end_marker(void)
{
init_oops_id();
printk(KERN_WARNING "---[ end trace %016llx ]---\n",
(unsigned long long)oops_id);
}
/*
* Called when the architecture exits its oops handler, after printing
* everything.
*/
void oops_exit(void)
{
do_oops_enter_exit();
print_oops_end_marker();
}
#ifdef WANT_WARN_ON_SLOWPATH
void warn_slowpath(const char *file, int line, const char *fmt, ...)
{
va_list args;
char function[KSYM_SYMBOL_LEN];
unsigned long caller = (unsigned long)__builtin_return_address(0);
const char *board;
sprint_symbol(function, caller);
printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
line, function);
board = dmi_get_system_info(DMI_PRODUCT_NAME);
if (board)
printk(KERN_WARNING "Hardware name: %s\n", board);
if (fmt) {
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
}
print_modules();
dump_stack();
print_oops_end_marker();
add_taint(TAINT_WARN);
}
EXPORT_SYMBOL(warn_slowpath);
#endif
#ifdef CONFIG_CC_STACKPROTECTOR
/*
* Called when gcc's -fstack-protector feature is used, and
* gcc detects corruption of the on-stack canary value
*/
void __stack_chk_fail(void)
{
panic("stack-protector: Kernel stack is corrupted in: %p\n",
__builtin_return_address(0));
}
EXPORT_SYMBOL(__stack_chk_fail);
#endif
core_param(panic, panic_timeout, int, 0644);
core_param(pause_on_oops, pause_on_oops, int, 0644);