[net-next-2.6.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', ' ' },
	{ TAINT_FIRMWARE_WORKAROUND,	'I', ' ' },
};

/**
 *	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.
 *  'I' - Working around severe firmware bug.
 *
 *	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,
				 unsigned taint, 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);
}

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),
			     TAINT_WARN, &args);
	va_end(args.args);
}
EXPORT_SYMBOL(warn_slowpath_fmt);

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

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

void warn_slowpath_null(const char *file, int line)
{
	warn_slowpath_common(file, line, __builtin_return_address(0),
			     TAINT_WARN, 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
1da177e4 LT	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	*/
c95dbf27 IM	11	#include <linux/debug_locks.h>
c95dbf27 IM	12	#include <linux/interrupt.h>
456b565c	13	#include <linux/kmsg_dump.h>
c95dbf27 IM	14	#include <linux/kallsyms.h>
c95dbf27 IM	15	#include <linux/notifier.h>
1da177e4	16	#include <linux/module.h>
c95dbf27	17	#include <linux/random.h>
1da177e4	18	#include <linux/reboot.h>
c95dbf27 IM	19	#include <linux/delay.h>
	20	#include <linux/kexec.h>
	21	#include <linux/sched.h>
1da177e4	22	#include <linux/sysrq.h>
c95dbf27	23	#include <linux/init.h>
1da177e4	24	#include <linux/nmi.h>
bd89bb29	25	#include <linux/dmi.h>
1da177e4	26
1da177e4	27	int panic_on_oops;
25ddbb18	28	static unsigned long tainted_mask;
dd287796 AM	29	static int pause_on_oops;
	30	static int pause_on_oops_flag;
	31	static DEFINE_SPINLOCK(pause_on_oops_lock);
1da177e4	32
dd287796	33	int panic_timeout;
1da177e4	34
e041c683	35	ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
1da177e4 LT	36
	37	EXPORT_SYMBOL(panic_notifier_list);
	38
1da177e4 LT	39	/* Returns how long it waited in ms */
	40	long (*panic_blink)(long time);
	41	EXPORT_SYMBOL(panic_blink);
	42
8aeee85a AB	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
1da177e4 LT	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	*/
1da177e4 LT	77	NORET_TYPE void panic(const char * fmt, ...)
1da177e4 LT	78	{
1da177e4 LT	79	static char buf[1024];
1da177e4 LT	80	va_list args;
c95dbf27	81	long i;
1da177e4	82
dc009d92	83	/*
c95dbf27 IM	84	* It's possible to come here directly from a panic-assertion and
c95dbf27 IM	85	* not have preempt disabled. Some functions called from here want
dc009d92 EB	86	* preempt to be disabled. No point enabling it later though...
	87	*/
	88	preempt_disable();
	89
1da177e4 LT	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);
5cb27301 IM	95	#ifdef CONFIG_DEBUG_BUGVERBOSE
	96	dump_stack();
	97	#endif
1da177e4	98
dc009d92 EB	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	*/
6e274d14	104	crash_kexec(NULL);
dc009d92	105
0f4bd46e KM	106	kmsg_dump(KMSG_DUMP_PANIC);
0f4bd46e KM	107
dc009d92 EB	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	*/
1da177e4	113	smp_send_stop();
1da177e4	114
e041c683	115	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
1da177e4	116
d014e889 AK	117	bust_spinlocks(0);
d014e889 AK	118
dc009d92	119	if (panic_timeout > 0) {
1da177e4	120	/*
c95dbf27 IM	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
8aeee85a	126	for (i = 0; i < panic_timeout; i++) {
1da177e4	127	touch_nmi_watchdog();
8aeee85a	128	panic_blink_one_second();
1da177e4	129	}
c95dbf27 IM	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.
1da177e4	134	*/
2f048ea8	135	emergency_restart();
1da177e4 LT	136	}
	137	#ifdef __sparc__
	138	{
	139	extern int stop_a_enabled;
a271c241	140	/* Make sure the user can actually press Stop-A (L1-A) */
1da177e4	141	stop_a_enabled = 1;
a271c241	142	printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
1da177e4 LT	143	}
1da177e4 LT	144	#endif
347a8dc3	145	#if defined(CONFIG_S390)
c95dbf27 IM	146	{
	147	unsigned long caller;
	148
	149	caller = (unsigned long)__builtin_return_address(0);
	150	disabled_wait(caller);
	151	}
1da177e4 LT	152	#endif
1da177e4 LT	153	local_irq_enable();
8aeee85a	154	while (1) {
c22db941	155	touch_softlockup_watchdog();
8aeee85a	156	panic_blink_one_second();
1da177e4 LT	157	}
	158	}
	159
	160	EXPORT_SYMBOL(panic);
	161
c277e63f	162
25ddbb18	163	struct tnt {
c95dbf27 IM	164	u8 bit;
	165	char true;
	166	char false;
25ddbb18 AK	167	};
	168
	169	static const struct tnt tnts[] = {
c95dbf27 IM	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', ' ' },
92946bc7	181	{ TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
25ddbb18 AK	182	};
25ddbb18 AK	183
1da177e4 LT	184	/**
	185	* print_tainted - return a string to represent the kernel taint state.
	186	*
	187	* 'P' - Proprietary module has been loaded.
	188	* 'F' - Module has been forcibly loaded.
	189	* 'S' - SMP with CPUs not designed for SMP.
	190	* 'R' - User forced a module unload.
9aa5e993	191	* 'M' - System experienced a machine check exception.
1da177e4	192	* 'B' - System has hit bad_page.
34f5a398	193	* 'U' - Userspace-defined naughtiness.
a8005992	194	* 'D' - Kernel has oopsed before
95b570c9 NH	195	* 'A' - ACPI table overridden.
95b570c9 NH	196	* 'W' - Taint on warning.
061b1bd3	197	* 'C' - modules from drivers/staging are loaded.
92946bc7	198	* 'I' - Working around severe firmware bug.
1da177e4	199	*
fe002a41	200	* The string is overwritten by the next call to print_tainted().
1da177e4	201	*/
1da177e4 LT	202	const char *print_tainted(void)
1da177e4 LT	203	{
25ddbb18 AK	204	static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
	205
	206	if (tainted_mask) {
	207	char *s;
	208	int i;
	209
	210	s = buf + sprintf(buf, "Tainted: ");
	211	for (i = 0; i < ARRAY_SIZE(tnts); i++) {
	212	const struct tnt *t = &tnts[i];
	213	*s++ = test_bit(t->bit, &tainted_mask) ?
	214	t->true : t->false;
	215	}
	216	*s = 0;
	217	} else
1da177e4	218	snprintf(buf, sizeof(buf), "Not tainted");
c95dbf27 IM	219
c95dbf27 IM	220	return buf;
1da177e4 LT	221	}
1da177e4 LT	222
25ddbb18	223	int test_taint(unsigned flag)
1da177e4	224	{
25ddbb18 AK	225	return test_bit(flag, &tainted_mask);
	226	}
	227	EXPORT_SYMBOL(test_taint);
	228
	229	unsigned long get_taint(void)
	230	{
	231	return tainted_mask;
1da177e4	232	}
dd287796	233
1da177e4	234	void add_taint(unsigned flag)
dd287796	235	{
9eeba613 FW	236	/*
	237	* Can't trust the integrity of the kernel anymore.
	238	* We don't call directly debug_locks_off() because the issue
	239	* is not necessarily serious enough to set oops_in_progress to 1
574bbe78 FW	240	* Also we want to keep up lockdep for staging development and
574bbe78 FW	241	* post-warning case.
9eeba613	242	*/
574bbe78	243	if (flag != TAINT_CRAP && flag != TAINT_WARN && __debug_locks_off())
b48ccb09	244	printk(KERN_WARNING "Disabling lock debugging due to kernel taint\n");
9eeba613	245
25ddbb18	246	set_bit(flag, &tainted_mask);
dd287796	247	}
1da177e4	248	EXPORT_SYMBOL(add_taint);
dd287796 AM	249
	250	static void spin_msec(int msecs)
	251	{
	252	int i;
	253
	254	for (i = 0; i < msecs; i++) {
	255	touch_nmi_watchdog();
	256	mdelay(1);
	257	}
	258	}
	259
	260	/*
	261	* It just happens that oops_enter() and oops_exit() are identically
	262	* implemented...
	263	*/
	264	static void do_oops_enter_exit(void)
	265	{
	266	unsigned long flags;
	267	static int spin_counter;
	268
	269	if (!pause_on_oops)
	270	return;
	271
	272	spin_lock_irqsave(&pause_on_oops_lock, flags);
	273	if (pause_on_oops_flag == 0) {
	274	/* This CPU may now print the oops message */
	275	pause_on_oops_flag = 1;
	276	} else {
	277	/* We need to stall this CPU */
	278	if (!spin_counter) {
	279	/* This CPU gets to do the counting */
	280	spin_counter = pause_on_oops;
	281	do {
	282	spin_unlock(&pause_on_oops_lock);
	283	spin_msec(MSEC_PER_SEC);
	284	spin_lock(&pause_on_oops_lock);
	285	} while (--spin_counter);
	286	pause_on_oops_flag = 0;
	287	} else {
	288	/* This CPU waits for a different one */
	289	while (spin_counter) {
	290	spin_unlock(&pause_on_oops_lock);
	291	spin_msec(1);
	292	spin_lock(&pause_on_oops_lock);
	293	}
	294	}
	295	}
	296	spin_unlock_irqrestore(&pause_on_oops_lock, flags);
	297	}
	298
	299	/*
c95dbf27 IM	300	* Return true if the calling CPU is allowed to print oops-related info.
c95dbf27 IM	301	* This is a bit racy..
dd287796 AM	302	*/
	303	int oops_may_print(void)
	304	{
	305	return pause_on_oops_flag == 0;
	306	}
	307
	308	/*
	309	* Called when the architecture enters its oops handler, before it prints
c95dbf27 IM	310	* anything. If this is the first CPU to oops, and it's oopsing the first
c95dbf27 IM	311	* time then let it proceed.
dd287796	312	*
c95dbf27 IM	313	* This is all enabled by the pause_on_oops kernel boot option. We do all
	314	* this to ensure that oopses don't scroll off the screen. It has the
	315	* side-effect of preventing later-oopsing CPUs from mucking up the display,
	316	* too.
dd287796	317	*
c95dbf27 IM	318	* It turns out that the CPU which is allowed to print ends up pausing for
	319	* the right duration, whereas all the other CPUs pause for twice as long:
	320	* once in oops_enter(), once in oops_exit().
dd287796 AM	321	*/
	322	void oops_enter(void)
	323	{
bdff7870	324	tracing_off();
c95dbf27 IM	325	/* can't trust the integrity of the kernel anymore: */
c95dbf27 IM	326	debug_locks_off();
dd287796 AM	327	do_oops_enter_exit();
	328	}
	329
2c3b20e9 AV	330	/*
	331	* 64-bit random ID for oopses:
	332	*/
	333	static u64 oops_id;
	334
	335	static int init_oops_id(void)
	336	{
	337	if (!oops_id)
	338	get_random_bytes(&oops_id, sizeof(oops_id));
d6624f99 AV	339	else
d6624f99 AV	340	oops_id++;
2c3b20e9 AV	341
	342	return 0;
	343	}
	344	late_initcall(init_oops_id);
	345
71c33911 AV	346	static void print_oops_end_marker(void)
	347	{
	348	init_oops_id();
	349	printk(KERN_WARNING "---[ end trace %016llx ]---\n",
	350	(unsigned long long)oops_id);
	351	}
	352
dd287796 AM	353	/*
	354	* Called when the architecture exits its oops handler, after printing
	355	* everything.
	356	*/
	357	void oops_exit(void)
	358	{
	359	do_oops_enter_exit();
71c33911	360	print_oops_end_marker();
456b565c	361	kmsg_dump(KMSG_DUMP_OOPS);
dd287796	362	}
3162f751	363
79b4cc5e	364	#ifdef WANT_WARN_ON_SLOWPATH
0f6f49a8 LT	365	struct slowpath_args {
0f6f49a8 LT	366	const char *fmt;
a8f18b90	367	va_list args;
0f6f49a8	368	};
bd89bb29	369
b2be0527 BH	370	static void warn_slowpath_common(const char file, int line, void caller,
b2be0527 BH	371	unsigned taint, struct slowpath_args *args)
0f6f49a8 LT	372	{
0f6f49a8 LT	373	const char *board;
a8f18b90 AV	374
a8f18b90 AV	375	printk(KERN_WARNING "------------[ cut here ]------------\n");
0f6f49a8	376	printk(KERN_WARNING "WARNING: at %s:%d %pS()\n", file, line, caller);
bd89bb29 AV	377	board = dmi_get_system_info(DMI_PRODUCT_NAME);
	378	if (board)
	379	printk(KERN_WARNING "Hardware name: %s\n", board);
74853dba	380
0f6f49a8 LT	381	if (args)
0f6f49a8 LT	382	vprintk(args->fmt, args->args);
a8f18b90 AV	383
	384	print_modules();
	385	dump_stack();
	386	print_oops_end_marker();
b2be0527	387	add_taint(taint);
a8f18b90	388	}
0f6f49a8 LT	389
	390	void warn_slowpath_fmt(const char file, int line, const char fmt, ...)
	391	{
	392	struct slowpath_args args;
	393
	394	args.fmt = fmt;
	395	va_start(args.args, fmt);
b2be0527 BH	396	warn_slowpath_common(file, line, __builtin_return_address(0),
b2be0527 BH	397	TAINT_WARN, &args);
0f6f49a8 LT	398	va_end(args.args);
0f6f49a8 LT	399	}
57adc4d2 AK	400	EXPORT_SYMBOL(warn_slowpath_fmt);
57adc4d2 AK	401
b2be0527 BH	402	void warn_slowpath_fmt_taint(const char *file, int line,
	403	unsigned taint, const char *fmt, ...)
	404	{
	405	struct slowpath_args args;
	406
	407	args.fmt = fmt;
	408	va_start(args.args, fmt);
	409	warn_slowpath_common(file, line, __builtin_return_address(0),
	410	taint, &args);
	411	va_end(args.args);
	412	}
	413	EXPORT_SYMBOL(warn_slowpath_fmt_taint);
	414
57adc4d2 AK	415	void warn_slowpath_null(const char *file, int line)
57adc4d2 AK	416	{
b2be0527 BH	417	warn_slowpath_common(file, line, __builtin_return_address(0),
b2be0527 BH	418	TAINT_WARN, NULL);
57adc4d2 AK	419	}
57adc4d2 AK	420	EXPORT_SYMBOL(warn_slowpath_null);
79b4cc5e AV	421	#endif
79b4cc5e AV	422
3162f751	423	#ifdef CONFIG_CC_STACKPROTECTOR
54371a43	424
3162f751 AV	425	/*
	426	* Called when gcc's -fstack-protector feature is used, and
	427	* gcc detects corruption of the on-stack canary value
	428	*/
	429	void __stack_chk_fail(void)
	430	{
517a92c4 IM	431	panic("stack-protector: Kernel stack is corrupted in: %p\n",
517a92c4 IM	432	__builtin_return_address(0));
3162f751 AV	433	}
3162f751 AV	434	EXPORT_SYMBOL(__stack_chk_fail);
54371a43	435
3162f751	436	#endif
f44dd164 RR	437
	438	core_param(panic, panic_timeout, int, 0644);
	439	core_param(pause_on_oops, pause_on_oops, int, 0644);