[linux.git] / kernel / stacktrace.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/stacktrace.c
 *
 * Stack trace management functions
 *
 *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <[email protected]>
 */
#include <linux/sched/task_stack.h>
#include <linux/sched/debug.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
#include <linux/interrupt.h>

/**
 * stack_trace_print - Print the entries in the stack trace
 * @entries:	Pointer to storage array
 * @nr_entries:	Number of entries in the storage array
 * @spaces:	Number of leading spaces to print
 */
void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
		       int spaces)
{
	unsigned int i;

	if (WARN_ON(!entries))
		return;

	for (i = 0; i < nr_entries; i++)
		printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
}
EXPORT_SYMBOL_GPL(stack_trace_print);

/**
 * stack_trace_snprint - Print the entries in the stack trace into a buffer
 * @buf:	Pointer to the print buffer
 * @size:	Size of the print buffer
 * @entries:	Pointer to storage array
 * @nr_entries:	Number of entries in the storage array
 * @spaces:	Number of leading spaces to print
 *
 * Return: Number of bytes printed.
 */
int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
			unsigned int nr_entries, int spaces)
{
	unsigned int generated, i, total = 0;

	if (WARN_ON(!entries))
		return 0;

	for (i = 0; i < nr_entries && size; i++) {
		generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
				     (void *)entries[i]);

		total += generated;
		if (generated >= size) {
			buf += size;
			size = 0;
		} else {
			buf += generated;
			size -= generated;
		}
	}

	return total;
}
EXPORT_SYMBOL_GPL(stack_trace_snprint);

#ifdef CONFIG_ARCH_STACKWALK

struct stacktrace_cookie {
	unsigned long	*store;
	unsigned int	size;
	unsigned int	skip;
	unsigned int	len;
};

static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
{
	struct stacktrace_cookie *c = cookie;

	if (c->len >= c->size)
		return false;

	if (c->skip > 0) {
		c->skip--;
		return true;
	}
	c->store[c->len++] = addr;
	return c->len < c->size;
}

static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
{
	if (in_sched_functions(addr))
		return true;
	return stack_trace_consume_entry(cookie, addr);
}

/**
 * stack_trace_save - Save a stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored.
 */
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
			      unsigned int skipnr)
{
	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	struct stacktrace_cookie c = {
		.store	= store,
		.size	= size,
		.skip	= skipnr + 1,
	};

	arch_stack_walk(consume_entry, &c, current, NULL);
	return c.len;
}
EXPORT_SYMBOL_GPL(stack_trace_save);

/**
 * stack_trace_save_tsk - Save a task stack trace into a storage array
 * @task:	The task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored.
 */
unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
				  unsigned int size, unsigned int skipnr)
{
	stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
	struct stacktrace_cookie c = {
		.store	= store,
		.size	= size,
		/* skip this function if they are tracing us */
		.skip	= skipnr + (current == tsk),
	};

	if (!try_get_task_stack(tsk))
		return 0;

	arch_stack_walk(consume_entry, &c, tsk, NULL);
	put_task_stack(tsk);
	return c.len;
}

/**
 * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
 * @regs:	Pointer to pt_regs to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored.
 */
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
				   unsigned int size, unsigned int skipnr)
{
	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	struct stacktrace_cookie c = {
		.store	= store,
		.size	= size,
		.skip	= skipnr,
	};

	arch_stack_walk(consume_entry, &c, current, regs);
	return c.len;
}

#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
/**
 * stack_trace_save_tsk_reliable - Save task stack with verification
 * @tsk:	Pointer to the task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return:	An error if it detects any unreliable features of the
 *		stack. Otherwise it guarantees that the stack trace is
 *		reliable and returns the number of entries stored.
 *
 * If the task is not 'current', the caller *must* ensure the task is inactive.
 */
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
				  unsigned int size)
{
	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	struct stacktrace_cookie c = {
		.store	= store,
		.size	= size,
	};
	int ret;

	/*
	 * If the task doesn't have a stack (e.g., a zombie), the stack is
	 * "reliably" empty.
	 */
	if (!try_get_task_stack(tsk))
		return 0;

	ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
	put_task_stack(tsk);
	return ret ? ret : c.len;
}
#endif

#ifdef CONFIG_USER_STACKTRACE_SUPPORT
/**
 * stack_trace_save_user - Save a user space stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return: Number of trace entries stored.
 */
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
{
	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	struct stacktrace_cookie c = {
		.store	= store,
		.size	= size,
	};
	mm_segment_t fs;

	/* Trace user stack if not a kernel thread */
	if (current->flags & PF_KTHREAD)
		return 0;

	fs = force_uaccess_begin();
	arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
	force_uaccess_end(fs);

	return c.len;
}
#endif

#else /* CONFIG_ARCH_STACKWALK */

/*
 * Architectures that do not implement save_stack_trace_*()
 * get these weak aliases and once-per-bootup warnings
 * (whenever this facility is utilized - for example by procfs):
 */
__weak void
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
	WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
}

__weak void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
	WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}

/**
 * stack_trace_save - Save a stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
			      unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		.skip		= skipnr + 1,
	};

	save_stack_trace(&trace);
	return trace.nr_entries;
}
EXPORT_SYMBOL_GPL(stack_trace_save);

/**
 * stack_trace_save_tsk - Save a task stack trace into a storage array
 * @task:	The task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_tsk(struct task_struct *task,
				  unsigned long *store, unsigned int size,
				  unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		/* skip this function if they are tracing us */
		.skip	= skipnr + (current == task),
	};

	save_stack_trace_tsk(task, &trace);
	return trace.nr_entries;
}

/**
 * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
 * @regs:	Pointer to pt_regs to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 * @skipnr:	Number of entries to skip at the start of the stack trace
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
				   unsigned int size, unsigned int skipnr)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
		.skip		= skipnr,
	};

	save_stack_trace_regs(regs, &trace);
	return trace.nr_entries;
}

#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
/**
 * stack_trace_save_tsk_reliable - Save task stack with verification
 * @tsk:	Pointer to the task to examine
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return:	An error if it detects any unreliable features of the
 *		stack. Otherwise it guarantees that the stack trace is
 *		reliable and returns the number of entries stored.
 *
 * If the task is not 'current', the caller *must* ensure the task is inactive.
 */
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
				  unsigned int size)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
	};
	int ret = save_stack_trace_tsk_reliable(tsk, &trace);

	return ret ? ret : trace.nr_entries;
}
#endif

#ifdef CONFIG_USER_STACKTRACE_SUPPORT
/**
 * stack_trace_save_user - Save a user space stack trace into a storage array
 * @store:	Pointer to storage array
 * @size:	Size of the storage array
 *
 * Return: Number of trace entries stored
 */
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
{
	struct stack_trace trace = {
		.entries	= store,
		.max_entries	= size,
	};

	save_stack_trace_user(&trace);
	return trace.nr_entries;
}
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */

#endif /* !CONFIG_ARCH_STACKWALK */

static inline bool in_irqentry_text(unsigned long ptr)
{
	return (ptr >= (unsigned long)&__irqentry_text_start &&
		ptr < (unsigned long)&__irqentry_text_end) ||
		(ptr >= (unsigned long)&__softirqentry_text_start &&
		 ptr < (unsigned long)&__softirqentry_text_end);
}

/**
 * filter_irq_stacks - Find first IRQ stack entry in trace
 * @entries:	Pointer to stack trace array
 * @nr_entries:	Number of entries in the storage array
 *
 * Return: Number of trace entries until IRQ stack starts.
 */
unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries)
{
	unsigned int i;

	for (i = 0; i < nr_entries; i++) {
		if (in_irqentry_text(entries[i])) {
			/* Include the irqentry function into the stack. */
			return i + 1;
		}
	}
	return nr_entries;
}
EXPORT_SYMBOL_GPL(filter_irq_stacks);
Commit	Line	Data
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
8637c099 IM	2	/*
	3	* kernel/stacktrace.c
	4	*
	5	* Stack trace management functions
	6	*
	7	* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <[email protected]>
	8	*/
214d8ca6 TG	9	#include <linux/sched/task_stack.h>
214d8ca6 TG	10	#include <linux/sched/debug.h>
8637c099	11	#include <linux/sched.h>
9212ddb5	12	#include <linux/kernel.h>
9984de1a	13	#include <linux/export.h>
8637c099 IM	14	#include <linux/kallsyms.h>
8637c099 IM	15	#include <linux/stacktrace.h>
f39f21b3	16	#include <linux/interrupt.h>
8637c099	17
e9b98e16 TG	18	/**
	19	* stack_trace_print - Print the entries in the stack trace
	20	* @entries: Pointer to storage array
	21	* @nr_entries: Number of entries in the storage array
	22	* @spaces: Number of leading spaces to print
	23	*/
a2970421	24	void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
e9b98e16	25	int spaces)
8637c099	26	{
e9b98e16	27	unsigned int i;
8637c099	28
e9b98e16	29	if (WARN_ON(!entries))
bfeeeeb9 JB	30	return;
bfeeeeb9 JB	31
e9b98e16 TG	32	for (i = 0; i < nr_entries; i++)
	33	printk("%c%pS\n", 1 + spaces, ' ', (void )entries[i]);
	34	}
	35	EXPORT_SYMBOL_GPL(stack_trace_print);
	36
e9b98e16 TG	37	/**
	38	* stack_trace_snprint - Print the entries in the stack trace into a buffer
	39	* @buf: Pointer to the print buffer
	40	* @size: Size of the print buffer
	41	* @entries: Pointer to storage array
	42	* @nr_entries: Number of entries in the storage array
	43	* @spaces: Number of leading spaces to print
	44	*
	45	* Return: Number of bytes printed.
	46	*/
a2970421	47	int stack_trace_snprint(char buf, size_t size, const unsigned long entries,
e9b98e16	48	unsigned int nr_entries, int spaces)
9a92a6ce	49	{
e9b98e16	50	unsigned int generated, i, total = 0;
9a92a6ce	51
e9b98e16	52	if (WARN_ON(!entries))
9a92a6ce JK	53	return 0;
9a92a6ce JK	54
e9b98e16	55	for (i = 0; i < nr_entries && size; i++) {
bfeda41d	56	generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
e9b98e16	57	(void *)entries[i]);
9a92a6ce JK	58
9a92a6ce JK	59	total += generated;
9a92a6ce JK	60	if (generated >= size) {
	61	buf += size;
	62	size = 0;
	63	} else {
	64	buf += generated;
	65	size -= generated;
	66	}
	67	}
	68
	69	return total;
	70	}
e9b98e16 TG	71	EXPORT_SYMBOL_GPL(stack_trace_snprint);
e9b98e16 TG	72
214d8ca6 TG	73	#ifdef CONFIG_ARCH_STACKWALK
	74
	75	struct stacktrace_cookie {
	76	unsigned long *store;
	77	unsigned int size;
	78	unsigned int skip;
	79	unsigned int len;
	80	};
	81
264c03a2	82	static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
214d8ca6 TG	83	{
	84	struct stacktrace_cookie *c = cookie;
	85
	86	if (c->len >= c->size)
	87	return false;
	88
	89	if (c->skip > 0) {
	90	c->skip--;
	91	return true;
	92	}
	93	c->store[c->len++] = addr;
	94	return c->len < c->size;
	95	}
	96
264c03a2	97	static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
214d8ca6 TG	98	{
	99	if (in_sched_functions(addr))
	100	return true;
264c03a2	101	return stack_trace_consume_entry(cookie, addr);
214d8ca6 TG	102	}
	103
	104	/**
	105	* stack_trace_save - Save a stack trace into a storage array
	106	* @store: Pointer to storage array
	107	* @size: Size of the storage array
	108	* @skipnr: Number of entries to skip at the start of the stack trace
	109	*
	110	* Return: Number of trace entries stored.
	111	*/
	112	unsigned int stack_trace_save(unsigned long *store, unsigned int size,
	113	unsigned int skipnr)
	114	{
	115	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	116	struct stacktrace_cookie c = {
	117	.store = store,
	118	.size = size,
	119	.skip = skipnr + 1,
	120	};
	121
	122	arch_stack_walk(consume_entry, &c, current, NULL);
	123	return c.len;
	124	}
	125	EXPORT_SYMBOL_GPL(stack_trace_save);
	126
	127	/**
	128	* stack_trace_save_tsk - Save a task stack trace into a storage array
	129	* @task: The task to examine
	130	* @store: Pointer to storage array
	131	* @size: Size of the storage array
	132	* @skipnr: Number of entries to skip at the start of the stack trace
	133	*
	134	* Return: Number of trace entries stored.
	135	*/
	136	unsigned int stack_trace_save_tsk(struct task_struct tsk, unsigned long store,
	137	unsigned int size, unsigned int skipnr)
	138	{
	139	stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
	140	struct stacktrace_cookie c = {
	141	.store = store,
	142	.size = size,
b0c51f15	143	/* skip this function if they are tracing us */
4b48512c	144	.skip = skipnr + (current == tsk),
214d8ca6 TG	145	};
	146
	147	if (!try_get_task_stack(tsk))
	148	return 0;
	149
	150	arch_stack_walk(consume_entry, &c, tsk, NULL);
	151	put_task_stack(tsk);
	152	return c.len;
	153	}
	154
	155	/**
	156	* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
	157	* @regs: Pointer to pt_regs to examine
	158	* @store: Pointer to storage array
	159	* @size: Size of the storage array
	160	* @skipnr: Number of entries to skip at the start of the stack trace
	161	*
	162	* Return: Number of trace entries stored.
	163	*/
	164	unsigned int stack_trace_save_regs(struct pt_regs regs, unsigned long store,
	165	unsigned int size, unsigned int skipnr)
	166	{
	167	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	168	struct stacktrace_cookie c = {
	169	.store = store,
	170	.size = size,
	171	.skip = skipnr,
	172	};
	173
	174	arch_stack_walk(consume_entry, &c, current, regs);
	175	return c.len;
	176	}
	177
	178	#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
	179	/**
	180	* stack_trace_save_tsk_reliable - Save task stack with verification
	181	* @tsk: Pointer to the task to examine
	182	* @store: Pointer to storage array
	183	* @size: Size of the storage array
	184	*
	185	* Return: An error if it detects any unreliable features of the
	186	* stack. Otherwise it guarantees that the stack trace is
	187	* reliable and returns the number of entries stored.
	188	*
	189	* If the task is not 'current', the caller must ensure the task is inactive.
	190	*/
	191	int stack_trace_save_tsk_reliable(struct task_struct tsk, unsigned long store,
	192	unsigned int size)
	193	{
	194	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	195	struct stacktrace_cookie c = {
	196	.store = store,
	197	.size = size,
	198	};
	199	int ret;
	200
	201	/*
	202	* If the task doesn't have a stack (e.g., a zombie), the stack is
	203	* "reliably" empty.
	204	*/
	205	if (!try_get_task_stack(tsk))
	206	return 0;
	207
	208	ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
209	put_task_stack(tsk);
7eaf51a2	210	return ret ? ret : c.len;
214d8ca6 TG	211	}
	212	#endif
	213
	214	#ifdef CONFIG_USER_STACKTRACE_SUPPORT
	215	/**
	216	* stack_trace_save_user - Save a user space stack trace into a storage array
	217	* @store: Pointer to storage array
	218	* @size: Size of the storage array
	219	*
	220	* Return: Number of trace entries stored.
	221	*/
	222	unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
	223	{
	224	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
	225	struct stacktrace_cookie c = {
	226	.store = store,
	227	.size = size,
	228	};
cac9b9a4	229	mm_segment_t fs;
214d8ca6 TG	230
214d8ca6 TG	231	/* Trace user stack if not a kernel thread */
7e8e6816	232	if (current->flags & PF_KTHREAD)
214d8ca6 TG	233	return 0;
214d8ca6 TG	234
3d13f313	235	fs = force_uaccess_begin();
214d8ca6	236	arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
3d13f313	237	force_uaccess_end(fs);
cac9b9a4	238
214d8ca6 TG	239	return c.len;
	240	}
	241	#endif
	242
	243	#else /* CONFIG_ARCH_STACKWALK */
	244
9212ddb5	245	/*
af085d90 JP	246	* Architectures that do not implement save_stack_trace_*()
af085d90 JP	247	* get these weak aliases and once-per-bootup warnings
c624d33f	248	* (whenever this facility is utilized - for example by procfs):
9212ddb5 IM	249	*/
	250	__weak void
	251	save_stack_trace_tsk(struct task_struct tsk, struct stack_trace trace)
	252	{
	253	WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
	254	}
c624d33f MH	255
	256	__weak void
	257	save_stack_trace_regs(struct pt_regs regs, struct stack_trace trace)
	258	{
	259	WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
	260	}
af085d90	261
e9b98e16 TG	262	/**
	263	* stack_trace_save - Save a stack trace into a storage array
	264	* @store: Pointer to storage array
	265	* @size: Size of the storage array
	266	* @skipnr: Number of entries to skip at the start of the stack trace
	267	*
	268	* Return: Number of trace entries stored
	269	*/
	270	unsigned int stack_trace_save(unsigned long *store, unsigned int size,
	271	unsigned int skipnr)
	272	{
	273	struct stack_trace trace = {
	274	.entries = store,
	275	.max_entries = size,
	276	.skip = skipnr + 1,
	277	};
	278
	279	save_stack_trace(&trace);
	280	return trace.nr_entries;
	281	}
	282	EXPORT_SYMBOL_GPL(stack_trace_save);
	283
	284	/**
	285	* stack_trace_save_tsk - Save a task stack trace into a storage array
	286	* @task: The task to examine
	287	* @store: Pointer to storage array
	288	* @size: Size of the storage array
	289	* @skipnr: Number of entries to skip at the start of the stack trace
	290	*
	291	* Return: Number of trace entries stored
	292	*/
	293	unsigned int stack_trace_save_tsk(struct task_struct *task,
	294	unsigned long *store, unsigned int size,
	295	unsigned int skipnr)
	296	{
	297	struct stack_trace trace = {
	298	.entries = store,
	299	.max_entries = size,
b0c51f15	300	/* skip this function if they are tracing us */
4b48512c	301	.skip = skipnr + (current == task),
e9b98e16 TG	302	};
	303
	304	save_stack_trace_tsk(task, &trace);
	305	return trace.nr_entries;
	306	}
	307
	308	/**
	309	* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
	310	* @regs: Pointer to pt_regs to examine
	311	* @store: Pointer to storage array
	312	* @size: Size of the storage array
	313	* @skipnr: Number of entries to skip at the start of the stack trace
	314	*
	315	* Return: Number of trace entries stored
	316	*/
	317	unsigned int stack_trace_save_regs(struct pt_regs regs, unsigned long store,
	318	unsigned int size, unsigned int skipnr)
	319	{
	320	struct stack_trace trace = {
	321	.entries = store,
	322	.max_entries = size,
	323	.skip = skipnr,
	324	};
	325
	326	save_stack_trace_regs(regs, &trace);
	327	return trace.nr_entries;
	328	}
	329
	330	#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
	331	/**
	332	* stack_trace_save_tsk_reliable - Save task stack with verification
	333	* @tsk: Pointer to the task to examine
	334	* @store: Pointer to storage array
	335	* @size: Size of the storage array
	336	*
	337	* Return: An error if it detects any unreliable features of the
	338	* stack. Otherwise it guarantees that the stack trace is
	339	* reliable and returns the number of entries stored.
	340	*
	341	* If the task is not 'current', the caller must ensure the task is inactive.
	342	*/
	343	int stack_trace_save_tsk_reliable(struct task_struct tsk, unsigned long store,
	344	unsigned int size)
	345	{
	346	struct stack_trace trace = {
	347	.entries = store,
	348	.max_entries = size,
	349	};
	350	int ret = save_stack_trace_tsk_reliable(tsk, &trace);
	351
	352	return ret ? ret : trace.nr_entries;
	353	}
	354	#endif
	355
	356	#ifdef CONFIG_USER_STACKTRACE_SUPPORT
	357	/**
	358	* stack_trace_save_user - Save a user space stack trace into a storage array
	359	* @store: Pointer to storage array
	360	* @size: Size of the storage array
	361	*
	362	* Return: Number of trace entries stored
	363	*/
	364	unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
	365	{
366	struct stack_trace trace = {
367	.entries = store,
368	.max_entries = size,
369	};
370
371	save_stack_trace_user(&trace);
372	return trace.nr_entries;
373	}
374	#endif /* CONFIG_USER_STACKTRACE_SUPPORT */
214d8ca6 TG	375
214d8ca6 TG	376	#endif /* !CONFIG_ARCH_STACKWALK */
f39f21b3 ME	377
	378	static inline bool in_irqentry_text(unsigned long ptr)
	379	{
	380	return (ptr >= (unsigned long)&__irqentry_text_start &&
	381	ptr < (unsigned long)&__irqentry_text_end) \|\|
	382	(ptr >= (unsigned long)&__softirqentry_text_start &&
	383	ptr < (unsigned long)&__softirqentry_text_end);
	384	}
	385
	386	/**
	387	* filter_irq_stacks - Find first IRQ stack entry in trace
	388	* @entries: Pointer to stack trace array
	389	* @nr_entries: Number of entries in the storage array
	390	*
	391	* Return: Number of trace entries until IRQ stack starts.
	392	*/
	393	unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries)
	394	{
	395	unsigned int i;
	396
	397	for (i = 0; i < nr_entries; i++) {
	398	if (in_irqentry_text(entries[i])) {
	399	/* Include the irqentry function into the stack. */
	400	return i + 1;
	401	}
	402	}
	403	return nr_entries;
	404	}
	405	EXPORT_SYMBOL_GPL(filter_irq_stacks);