[linux-2.6-block.git] / kernel / panic.c

/*
 *  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/kmsg_dump.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);

/* Returns how long it waited in ms */
long (*panic_blink)(long time);
EXPORT_SYMBOL(panic_blink);

static void panic_blink_one_second(void)
{
	static long i = 0, end;

	if (panic_blink) {
		end = i + MSEC_PER_SEC;

		while (i < end) {
			i += panic_blink(i);
			mdelay(1);
			i++;
		}
	} else {
		/*
		 * When running under a hypervisor a small mdelay may get
		 * rounded up to the hypervisor timeslice. For example, with
		 * a 1ms in 10ms hypervisor timeslice we might inflate a
		 * mdelay(1) loop by 10x.
		 *
		 * If we have nothing to blink, spin on 1 second calls to
		 * mdelay to avoid this.
		 */
		mdelay(MSEC_PER_SEC);
	}
}

/**
 *	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);

	kmsg_dump(KMSG_DUMP_PANIC);

	/*
	 * 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);

	bust_spinlocks(0);

	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; i++) {
			touch_nmi_watchdog();
			panic_blink_one_second();
		}
		/*
		 * 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();
	while (1) {
		touch_softlockup_watchdog();
		panic_blink_one_second();
	}
}

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_tainted().
 */
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)
{
	tracing_off();
	/* 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();
	kmsg_dump(KMSG_DUMP_OOPS);
}

#ifdef WANT_WARN_ON_SLOWPATH
struct slowpath_args {
	const char *fmt;
	va_list args;
};

static void warn_slowpath_common(const char *file, int line, void *caller, struct slowpath_args *args)
{
	const char *board;

	printk(KERN_WARNING "------------[ cut here ]------------\n");
	printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
	board = dmi_get_system_info(DMI_PRODUCT_NAME);
	if (board)
		printk(KERN_WARNING "Hardware name: %s\n", board);

	if (args)
		vprintk(args->fmt, args->args);

	print_modules();
	dump_stack();
	print_oops_end_marker();
	add_taint(TAINT_WARN);
}

void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
{
	struct slowpath_args args;

	args.fmt = fmt;
	va_start(args.args, fmt);
	warn_slowpath_common(file, line, __builtin_return_address(0), &args);
	va_end(args.args);
}
EXPORT_SYMBOL(warn_slowpath_fmt);

void warn_slowpath_null(const char *file, int line)
{
	warn_slowpath_common(file, line, __builtin_return_address(0), NULL);
}
EXPORT_SYMBOL(warn_slowpath_null);
#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);
Commit	Line	Data
	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/debug_locks.h>
	12	#include <linux/interrupt.h>
	13	#include <linux/kmsg_dump.h>
	14	#include <linux/kallsyms.h>
	15	#include <linux/notifier.h>
	16	#include <linux/module.h>
	17	#include <linux/random.h>
	18	#include <linux/reboot.h>
	19	#include <linux/delay.h>
	20	#include <linux/kexec.h>
	21	#include <linux/sched.h>
	22	#include <linux/sysrq.h>
	23	#include <linux/init.h>
	24	#include <linux/nmi.h>
	25	#include <linux/dmi.h>
	26
	27	int panic_on_oops;
	28	static unsigned long tainted_mask;
	29	static int pause_on_oops;
	30	static int pause_on_oops_flag;
	31	static DEFINE_SPINLOCK(pause_on_oops_lock);
	32
	33	int panic_timeout;
	34
	35	ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
	36
	37	EXPORT_SYMBOL(panic_notifier_list);
	38
	39	/* Returns how long it waited in ms */
	40	long (*panic_blink)(long time);
	41	EXPORT_SYMBOL(panic_blink);
	42
	43	static void panic_blink_one_second(void)
	44	{
	45	static long i = 0, end;
	46
	47	if (panic_blink) {
	48	end = i + MSEC_PER_SEC;
	49
	50	while (i < end) {
	51	i += panic_blink(i);
	52	mdelay(1);
	53	i++;
	54	}
	55	} else {
	56	/*
	57	* When running under a hypervisor a small mdelay may get
	58	* rounded up to the hypervisor timeslice. For example, with
	59	* a 1ms in 10ms hypervisor timeslice we might inflate a
	60	* mdelay(1) loop by 10x.
	61	*
	62	* If we have nothing to blink, spin on 1 second calls to
	63	* mdelay to avoid this.
	64	*/
	65	mdelay(MSEC_PER_SEC);
	66	}
	67	}
	68
	69	/**
	70	* panic - halt the system
	71	* @fmt: The text string to print
	72	*
	73	* Display a message, then perform cleanups.
	74	*
	75	* This function never returns.
	76	*/
	77	NORET_TYPE void panic(const char * fmt, ...)
	78	{
	79	static char buf[1024];
	80	va_list args;
	81	long i;
	82
	83	/*
	84	* It's possible to come here directly from a panic-assertion and
	85	* not have preempt disabled. Some functions called from here want
	86	* preempt to be disabled. No point enabling it later though...
	87	*/
	88	preempt_disable();
	89
	90	bust_spinlocks(1);
	91	va_start(args, fmt);
	92	vsnprintf(buf, sizeof(buf), fmt, args);
	93	va_end(args);
	94	printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
	95	#ifdef CONFIG_DEBUG_BUGVERBOSE
	96	dump_stack();
	97	#endif
	98
	99	/*
	100	* If we have crashed and we have a crash kernel loaded let it handle
	101	* everything else.
	102	* Do we want to call this before we try to display a message?
	103	*/
	104	crash_kexec(NULL);
	105
	106	kmsg_dump(KMSG_DUMP_PANIC);
	107
	108	/*
	109	* Note smp_send_stop is the usual smp shutdown function, which
	110	* unfortunately means it may not be hardened to work in a panic
	111	* situation.
	112	*/
	113	smp_send_stop();
	114
	115	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
	116
	117	bust_spinlocks(0);
	118
	119	if (panic_timeout > 0) {
	120	/*
	121	* Delay timeout seconds before rebooting the machine.
	122	* We can't use the "normal" timers since we just panicked.
	123	*/
	124	printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
	125
	126	for (i = 0; i < panic_timeout; i++) {
	127	touch_nmi_watchdog();
	128	panic_blink_one_second();
	129	}
	130	/*
	131	* This will not be a clean reboot, with everything
	132	* shutting down. But if there is a chance of
	133	* rebooting the system it will be rebooted.
	134	*/
	135	emergency_restart();
	136	}
	137	#ifdef __sparc__
	138	{
	139	extern int stop_a_enabled;
	140	/* Make sure the user can actually press Stop-A (L1-A) */
	141	stop_a_enabled = 1;
	142	printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
	143	}
	144	#endif
	145	#if defined(CONFIG_S390)
	146	{
	147	unsigned long caller;
	148
	149	caller = (unsigned long)__builtin_return_address(0);
	150	disabled_wait(caller);
	151	}
	152	#endif
	153	local_irq_enable();
	154	while (1) {
	155	touch_softlockup_watchdog();
	156	panic_blink_one_second();
	157	}
	158	}
	159
	160	EXPORT_SYMBOL(panic);
	161
	162
	163	struct tnt {
	164	u8 bit;
	165	char true;
	166	char false;
	167	};
	168
	169	static const struct tnt tnts[] = {
	170	{ TAINT_PROPRIETARY_MODULE, 'P', 'G' },
	171	{ TAINT_FORCED_MODULE, 'F', ' ' },
	172	{ TAINT_UNSAFE_SMP, 'S', ' ' },
	173	{ TAINT_FORCED_RMMOD, 'R', ' ' },
	174	{ TAINT_MACHINE_CHECK, 'M', ' ' },
	175	{ TAINT_BAD_PAGE, 'B', ' ' },
	176	{ TAINT_USER, 'U', ' ' },
	177	{ TAINT_DIE, 'D', ' ' },
	178	{ TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
	179	{ TAINT_WARN, 'W', ' ' },
	180	{ TAINT_CRAP, 'C', ' ' },
	181	};
	182
	183	/**
	184	* print_tainted - return a string to represent the kernel taint state.
	185	*
	186	* 'P' - Proprietary module has been loaded.
	187	* 'F' - Module has been forcibly loaded.
	188	* 'S' - SMP with CPUs not designed for SMP.
	189	* 'R' - User forced a module unload.
	190	* 'M' - System experienced a machine check exception.
	191	* 'B' - System has hit bad_page.
	192	* 'U' - Userspace-defined naughtiness.
	193	* 'D' - Kernel has oopsed before
	194	* 'A' - ACPI table overridden.
	195	* 'W' - Taint on warning.
	196	* 'C' - modules from drivers/staging are loaded.
	197	*
	198	* The string is overwritten by the next call to print_tainted().
	199	*/
	200	const char *print_tainted(void)
	201	{
	202	static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
	203
	204	if (tainted_mask) {
	205	char *s;
	206	int i;
	207
	208	s = buf + sprintf(buf, "Tainted: ");
	209	for (i = 0; i < ARRAY_SIZE(tnts); i++) {
	210	const struct tnt *t = &tnts[i];
	211	*s++ = test_bit(t->bit, &tainted_mask) ?
	212	t->true : t->false;
	213	}
	214	*s = 0;
	215	} else
	216	snprintf(buf, sizeof(buf), "Not tainted");
	217
	218	return buf;
	219	}
	220
	221	int test_taint(unsigned flag)
	222	{
	223	return test_bit(flag, &tainted_mask);
	224	}
	225	EXPORT_SYMBOL(test_taint);
	226
	227	unsigned long get_taint(void)
	228	{
	229	return tainted_mask;
	230	}
	231
	232	void add_taint(unsigned flag)
	233	{
	234	/*
	235	* Can't trust the integrity of the kernel anymore.
	236	* We don't call directly debug_locks_off() because the issue
	237	* is not necessarily serious enough to set oops_in_progress to 1
	238	* Also we want to keep up lockdep for staging development and
	239	* post-warning case.
	240	*/
	241	if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
	242	printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
	243
	244	set_bit(flag, &tainted_mask);
	245	}
	246	EXPORT_SYMBOL(add_taint);
	247
	248	static void spin_msec(int msecs)
	249	{
	250	int i;
	251
	252	for (i = 0; i < msecs; i++) {
	253	touch_nmi_watchdog();
	254	mdelay(1);
	255	}
	256	}
	257
	258	/*
	259	* It just happens that oops_enter() and oops_exit() are identically
	260	* implemented...
	261	*/
	262	static void do_oops_enter_exit(void)
	263	{
	264	unsigned long flags;
	265	static int spin_counter;
	266
	267	if (!pause_on_oops)
	268	return;
	269
	270	spin_lock_irqsave(&pause_on_oops_lock, flags);
	271	if (pause_on_oops_flag == 0) {
	272	/* This CPU may now print the oops message */
	273	pause_on_oops_flag = 1;
	274	} else {
	275	/* We need to stall this CPU */
	276	if (!spin_counter) {
	277	/* This CPU gets to do the counting */
	278	spin_counter = pause_on_oops;
	279	do {
	280	spin_unlock(&pause_on_oops_lock);
	281	spin_msec(MSEC_PER_SEC);
	282	spin_lock(&pause_on_oops_lock);
	283	} while (--spin_counter);
	284	pause_on_oops_flag = 0;
	285	} else {
	286	/* This CPU waits for a different one */
	287	while (spin_counter) {
	288	spin_unlock(&pause_on_oops_lock);
	289	spin_msec(1);
	290	spin_lock(&pause_on_oops_lock);
	291	}
	292	}
	293	}
	294	spin_unlock_irqrestore(&pause_on_oops_lock, flags);
	295	}
	296
	297	/*
	298	* Return true if the calling CPU is allowed to print oops-related info.
	299	* This is a bit racy..
	300	*/
	301	int oops_may_print(void)
	302	{
	303	return pause_on_oops_flag == 0;
	304	}
	305
	306	/*
	307	* Called when the architecture enters its oops handler, before it prints
	308	* anything. If this is the first CPU to oops, and it's oopsing the first
	309	* time then let it proceed.
	310	*
	311	* This is all enabled by the pause_on_oops kernel boot option. We do all
	312	* this to ensure that oopses don't scroll off the screen. It has the
	313	* side-effect of preventing later-oopsing CPUs from mucking up the display,
	314	* too.
	315	*
	316	* It turns out that the CPU which is allowed to print ends up pausing for
	317	* the right duration, whereas all the other CPUs pause for twice as long:
	318	* once in oops_enter(), once in oops_exit().
	319	*/
	320	void oops_enter(void)
	321	{
	322	tracing_off();
	323	/* can't trust the integrity of the kernel anymore: */
	324	debug_locks_off();
	325	do_oops_enter_exit();
	326	}
	327
	328	/*
	329	* 64-bit random ID for oopses:
	330	*/
	331	static u64 oops_id;
	332
	333	static int init_oops_id(void)
	334	{
	335	if (!oops_id)
	336	get_random_bytes(&oops_id, sizeof(oops_id));
	337	else
	338	oops_id++;
	339
	340	return 0;
	341	}
	342	late_initcall(init_oops_id);
	343
	344	static void print_oops_end_marker(void)
	345	{
	346	init_oops_id();
	347	printk(KERN_WARNING "---[ end trace %016llx ]---\n",
	348	(unsigned long long)oops_id);
	349	}
	350
	351	/*
	352	* Called when the architecture exits its oops handler, after printing
	353	* everything.
	354	*/
	355	void oops_exit(void)
	356	{
	357	do_oops_enter_exit();
	358	print_oops_end_marker();
	359	kmsg_dump(KMSG_DUMP_OOPS);
	360	}
	361
	362	#ifdef WANT_WARN_ON_SLOWPATH
	363	struct slowpath_args {
	364	const char *fmt;
	365	va_list args;
	366	};
	367
	368	static void warn_slowpath_common(const char file, int line, void caller, struct slowpath_args *args)
	369	{
	370	const char *board;
	371
	372	printk(KERN_WARNING "------------[ cut here ]------------\n");
	373	printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
	374	board = dmi_get_system_info(DMI_PRODUCT_NAME);
	375	if (board)
	376	printk(KERN_WARNING "Hardware name: %s\n", board);
	377
	378	if (args)
	379	vprintk(args->fmt, args->args);
	380
	381	print_modules();
	382	dump_stack();
	383	print_oops_end_marker();
	384	add_taint(TAINT_WARN);
	385	}
	386
	387	void warn_slowpath_fmt(const char file, int line, const char fmt, ...)
	388	{
	389	struct slowpath_args args;
	390
	391	args.fmt = fmt;
	392	va_start(args.args, fmt);
	393	warn_slowpath_common(file, line, __builtin_return_address(0), &args);
	394	va_end(args.args);
	395	}
	396	EXPORT_SYMBOL(warn_slowpath_fmt);
	397
	398	void warn_slowpath_null(const char *file, int line)
	399	{
	400	warn_slowpath_common(file, line, __builtin_return_address(0), NULL);
	401	}
	402	EXPORT_SYMBOL(warn_slowpath_null);
	403	#endif
	404
	405	#ifdef CONFIG_CC_STACKPROTECTOR
	406
	407	/*
	408	* Called when gcc's -fstack-protector feature is used, and
	409	* gcc detects corruption of the on-stack canary value
	410	*/
	411	void __stack_chk_fail(void)
	412	{
	413	panic("stack-protector: Kernel stack is corrupted in: %p\n",
	414	__builtin_return_address(0));
	415	}
	416	EXPORT_SYMBOL(__stack_chk_fail);
	417
	418	#endif
	419
	420	core_param(panic, panic_timeout, int, 0644);
	421	core_param(pause_on_oops, pause_on_oops, int, 0644);