[linux.git] / lib / fault-inject.c

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/stat.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
#include <linux/fault-inject.h>

/*
 * setup_fault_attr() is a helper function for various __setup handlers, so it
 * returns 0 on error, because that is what __setup handlers do.
 */
int __init setup_fault_attr(struct fault_attr *attr, char *str)
{
	unsigned long probability;
	unsigned long interval;
	int times;
	int space;

	/* "<interval>,<probability>,<space>,<times>" */
	if (sscanf(str, "%lu,%lu,%d,%d",
			&interval, &probability, &space, &times) < 4) {
		printk(KERN_WARNING
			"FAULT_INJECTION: failed to parse arguments\n");
		return 0;
	}

	attr->probability = probability;
	attr->interval = interval;
	atomic_set(&attr->times, times);
	atomic_set(&attr->space, space);

	return 1;
}

static void fail_dump(struct fault_attr *attr)
{
	if (attr->verbose > 0)
		printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
	if (attr->verbose > 1)
		dump_stack();
}

#define atomic_dec_not_zero(v)		atomic_add_unless((v), -1, 0)

static bool fail_task(struct fault_attr *attr, struct task_struct *task)
{
	return !in_interrupt() && task->make_it_fail;
}

#define MAX_STACK_TRACE_DEPTH 32

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

static bool fail_stacktrace(struct fault_attr *attr)
{
	struct stack_trace trace;
	int depth = attr->stacktrace_depth;
	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	int n;
	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);

	if (depth == 0)
		return found;

	trace.nr_entries = 0;
	trace.entries = entries;
	trace.max_entries = depth;
	trace.skip = 1;

	save_stack_trace(&trace);
	for (n = 0; n < trace.nr_entries; n++) {
		if (attr->reject_start <= entries[n] &&
			       entries[n] < attr->reject_end)
			return false;
		if (attr->require_start <= entries[n] &&
			       entries[n] < attr->require_end)
			found = true;
	}
	return found;
}

#else

static inline bool fail_stacktrace(struct fault_attr *attr)
{
	return true;
}

#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

/*
 * This code is stolen from failmalloc-1.0
 * http://www.nongnu.org/failmalloc/
 */

bool should_fail(struct fault_attr *attr, ssize_t size)
{
	if (attr->task_filter && !fail_task(attr, current))
		return false;

	if (atomic_read(&attr->times) == 0)
		return false;

	if (atomic_read(&attr->space) > size) {
		atomic_sub(size, &attr->space);
		return false;
	}

	if (attr->interval > 1) {
		attr->count++;
		if (attr->count % attr->interval)
			return false;
	}

	if (attr->probability <= random32() % 100)
		return false;

	if (!fail_stacktrace(attr))
		return false;

	fail_dump(attr);

	if (atomic_read(&attr->times) != -1)
		atomic_dec_not_zero(&attr->times);

	return true;
}

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

static int debugfs_ul_set(void *data, u64 val)
{
	*(unsigned long *)data = val;
	return 0;
}

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
static int debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
{
	*(unsigned long *)data =
		val < MAX_STACK_TRACE_DEPTH ?
		val : MAX_STACK_TRACE_DEPTH;
	return 0;
}
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

static int debugfs_ul_get(void *data, u64 *val)
{
	*val = *(unsigned long *)data;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");

static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
				struct dentry *parent, unsigned long *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_ul);
}

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
			debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");

static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
	const char *name, mode_t mode,
	struct dentry *parent, unsigned long *value)
{
	return debugfs_create_file(name, mode, parent, value,
				   &fops_ul_MAX_STACK_TRACE_DEPTH);
}
#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

static int debugfs_atomic_t_set(void *data, u64 val)
{
	atomic_set((atomic_t *)data, val);
	return 0;
}

static int debugfs_atomic_t_get(void *data, u64 *val)
{
	*val = atomic_read((atomic_t *)data);
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
			debugfs_atomic_t_set, "%lld\n");

static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
				struct dentry *parent, atomic_t *value)
{
	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
}

void cleanup_fault_attr_dentries(struct fault_attr *attr)
{
	debugfs_remove(attr->dentries.probability_file);
	attr->dentries.probability_file = NULL;

	debugfs_remove(attr->dentries.interval_file);
	attr->dentries.interval_file = NULL;

	debugfs_remove(attr->dentries.times_file);
	attr->dentries.times_file = NULL;

	debugfs_remove(attr->dentries.space_file);
	attr->dentries.space_file = NULL;

	debugfs_remove(attr->dentries.verbose_file);
	attr->dentries.verbose_file = NULL;

	debugfs_remove(attr->dentries.task_filter_file);
	attr->dentries.task_filter_file = NULL;

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

	debugfs_remove(attr->dentries.stacktrace_depth_file);
	attr->dentries.stacktrace_depth_file = NULL;

	debugfs_remove(attr->dentries.require_start_file);
	attr->dentries.require_start_file = NULL;

	debugfs_remove(attr->dentries.require_end_file);
	attr->dentries.require_end_file = NULL;

	debugfs_remove(attr->dentries.reject_start_file);
	attr->dentries.reject_start_file = NULL;

	debugfs_remove(attr->dentries.reject_end_file);
	attr->dentries.reject_end_file = NULL;

#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

	if (attr->dentries.dir)
		WARN_ON(!simple_empty(attr->dentries.dir));

	debugfs_remove(attr->dentries.dir);
	attr->dentries.dir = NULL;
}

int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
{
	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;

	memset(&attr->dentries, 0, sizeof(attr->dentries));

	dir = debugfs_create_dir(name, NULL);
	if (!dir)
		goto fail;
	attr->dentries.dir = dir;

	attr->dentries.probability_file =
		debugfs_create_ul("probability", mode, dir, &attr->probability);

	attr->dentries.interval_file =
		debugfs_create_ul("interval", mode, dir, &attr->interval);

	attr->dentries.times_file =
		debugfs_create_atomic_t("times", mode, dir, &attr->times);

	attr->dentries.space_file =
		debugfs_create_atomic_t("space", mode, dir, &attr->space);

	attr->dentries.verbose_file =
		debugfs_create_ul("verbose", mode, dir, &attr->verbose);

	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
						mode, dir, &attr->task_filter);

	if (!attr->dentries.probability_file || !attr->dentries.interval_file ||
	    !attr->dentries.times_file || !attr->dentries.space_file ||
	    !attr->dentries.verbose_file || !attr->dentries.task_filter_file)
		goto fail;

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

	attr->dentries.stacktrace_depth_file =
		debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
			"stacktrace-depth", mode, dir, &attr->stacktrace_depth);

	attr->dentries.require_start_file =
		debugfs_create_ul("require-start", mode, dir, &attr->require_start);

	attr->dentries.require_end_file =
		debugfs_create_ul("require-end", mode, dir, &attr->require_end);

	attr->dentries.reject_start_file =
		debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);

	attr->dentries.reject_end_file =
		debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);

	if (!attr->dentries.stacktrace_depth_file ||
	    !attr->dentries.require_start_file ||
	    !attr->dentries.require_end_file ||
	    !attr->dentries.reject_start_file ||
	    !attr->dentries.reject_end_file)
		goto fail;

#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

	return 0;
fail:
	cleanup_fault_attr_dentries(attr);
	return -ENOMEM;
}

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
Commit	Line	Data
6ff1cb35 AM	1	#include <linux/kernel.h>
	2	#include <linux/init.h>
	3	#include <linux/random.h>
	4	#include <linux/stat.h>
	5	#include <linux/types.h>
	6	#include <linux/fs.h>
	7	#include <linux/module.h>
f4f154fd	8	#include <linux/interrupt.h>
329409ae AM	9	#include <linux/stacktrace.h>
329409ae AM	10	#include <linux/kallsyms.h>
6ff1cb35 AM	11	#include <linux/fault-inject.h>
	12
	13	/*
	14	* setup_fault_attr() is a helper function for various __setup handlers, so it
	15	* returns 0 on error, because that is what __setup handlers do.
	16	*/
	17	int __init setup_fault_attr(struct fault_attr attr, char str)
	18	{
	19	unsigned long probability;
	20	unsigned long interval;
	21	int times;
	22	int space;
	23
	24	/* "<interval>,<probability>,<space>,<times>" */
	25	if (sscanf(str, "%lu,%lu,%d,%d",
	26	&interval, &probability, &space, &times) < 4) {
	27	printk(KERN_WARNING
	28	"FAULT_INJECTION: failed to parse arguments\n");
	29	return 0;
	30	}
	31
	32	attr->probability = probability;
	33	attr->interval = interval;
	34	atomic_set(&attr->times, times);
	35	atomic_set(&attr->space, space);
	36
	37	return 1;
	38	}
	39
	40	static void fail_dump(struct fault_attr *attr)
	41	{
	42	if (attr->verbose > 0)
	43	printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
	44	if (attr->verbose > 1)
	45	dump_stack();
	46	}
	47
	48	#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
	49
08b3df2d	50	static bool fail_task(struct fault_attr attr, struct task_struct task)
f4f154fd AM	51	{
	52	return !in_interrupt() && task->make_it_fail;
	53	}
	54
a124c28e DM	55	#define MAX_STACK_TRACE_DEPTH 32
a124c28e DM	56
1df49008	57	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
329409ae	58
08b3df2d	59	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	60	{
	61	struct stack_trace trace;
	62	int depth = attr->stacktrace_depth;
	63	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	64	int n;
	65	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	66
	67	if (depth == 0)
	68	return found;
	69
	70	trace.nr_entries = 0;
	71	trace.entries = entries;
a124c28e	72	trace.max_entries = depth;
329409ae	73	trace.skip = 1;
329409ae	74
ab1b6f03	75	save_stack_trace(&trace);
329409ae AM	76	for (n = 0; n < trace.nr_entries; n++) {
	77	if (attr->reject_start <= entries[n] &&
	78	entries[n] < attr->reject_end)
08b3df2d	79	return false;
329409ae AM	80	if (attr->require_start <= entries[n] &&
329409ae AM	81	entries[n] < attr->require_end)
08b3df2d	82	found = true;
329409ae AM	83	}
	84	return found;
	85	}
	86
	87	#else
	88
08b3df2d	89	static inline bool fail_stacktrace(struct fault_attr *attr)
329409ae	90	{
1df49008	91	return true;
329409ae AM	92	}
329409ae AM	93
1df49008	94	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
329409ae	95
6ff1cb35 AM	96	/*
	97	* This code is stolen from failmalloc-1.0
	98	* http://www.nongnu.org/failmalloc/
	99	*/
	100
08b3df2d	101	bool should_fail(struct fault_attr *attr, ssize_t size)
6ff1cb35	102	{
f4f154fd	103	if (attr->task_filter && !fail_task(attr, current))
08b3df2d	104	return false;
f4f154fd	105
6ff1cb35	106	if (atomic_read(&attr->times) == 0)
08b3df2d	107	return false;
6ff1cb35 AM	108
	109	if (atomic_read(&attr->space) > size) {
	110	atomic_sub(size, &attr->space);
08b3df2d	111	return false;
6ff1cb35 AM	112	}
	113
	114	if (attr->interval > 1) {
	115	attr->count++;
	116	if (attr->count % attr->interval)
08b3df2d	117	return false;
6ff1cb35 AM	118	}
6ff1cb35 AM	119
f1729c28 DM	120	if (attr->probability <= random32() % 100)
f1729c28 DM	121	return false;
6ff1cb35	122
f1729c28 DM	123	if (!fail_stacktrace(attr))
f1729c28 DM	124	return false;
6ff1cb35	125
6ff1cb35 AM	126	fail_dump(attr);
	127
	128	if (atomic_read(&attr->times) != -1)
	129	atomic_dec_not_zero(&attr->times);
	130
08b3df2d	131	return true;
6ff1cb35 AM	132	}
	133
	134	#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	135
8b88b099	136	static int debugfs_ul_set(void *data, u64 val)
6ff1cb35 AM	137	{
6ff1cb35 AM	138	(unsigned long )data = val;
8b88b099	139	return 0;
6ff1cb35 AM	140	}
6ff1cb35 AM	141
6ddb23c7	142	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
8b88b099	143	static int debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
a124c28e DM	144	{
	145	(unsigned long )data =
	146	val < MAX_STACK_TRACE_DEPTH ?
	147	val : MAX_STACK_TRACE_DEPTH;
8b88b099	148	return 0;
a124c28e	149	}
6ddb23c7	150	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
a124c28e	151
8b88b099	152	static int debugfs_ul_get(void data, u64 val)
6ff1cb35	153	{
8b88b099 CH	154	val = (unsigned long *)data;
8b88b099 CH	155	return 0;
6ff1cb35 AM	156	}
	157
	158	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	159
	160	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	161	struct dentry parent, unsigned long value)
	162	{
	163	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	164	}
	165
6ddb23c7	166	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
a124c28e DM	167	DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
	168	debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
	169
	170	static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
	171	const char *name, mode_t mode,
	172	struct dentry parent, unsigned long value)
	173	{
	174	return debugfs_create_file(name, mode, parent, value,
	175	&fops_ul_MAX_STACK_TRACE_DEPTH);
	176	}
6ddb23c7	177	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
a124c28e	178
8b88b099	179	static int debugfs_atomic_t_set(void *data, u64 val)
6ff1cb35 AM	180	{
6ff1cb35 AM	181	atomic_set((atomic_t *)data, val);
8b88b099	182	return 0;
6ff1cb35 AM	183	}
6ff1cb35 AM	184
8b88b099	185	static int debugfs_atomic_t_get(void data, u64 val)
6ff1cb35	186	{
8b88b099 CH	187	val = atomic_read((atomic_t )data);
8b88b099 CH	188	return 0;
6ff1cb35 AM	189	}
	190
	191	DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
	192	debugfs_atomic_t_set, "%lld\n");
	193
	194	static struct dentry debugfs_create_atomic_t(const char name, mode_t mode,
	195	struct dentry parent, atomic_t value)
	196	{
	197	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
	198	}
	199
	200	void cleanup_fault_attr_dentries(struct fault_attr *attr)
	201	{
	202	debugfs_remove(attr->dentries.probability_file);
	203	attr->dentries.probability_file = NULL;
	204
	205	debugfs_remove(attr->dentries.interval_file);
	206	attr->dentries.interval_file = NULL;
	207
	208	debugfs_remove(attr->dentries.times_file);
	209	attr->dentries.times_file = NULL;
	210
	211	debugfs_remove(attr->dentries.space_file);
	212	attr->dentries.space_file = NULL;
	213
	214	debugfs_remove(attr->dentries.verbose_file);
	215	attr->dentries.verbose_file = NULL;
	216
f4f154fd AM	217	debugfs_remove(attr->dentries.task_filter_file);
	218	attr->dentries.task_filter_file = NULL;
	219
1df49008 AM	220	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
1df49008 AM	221
329409ae AM	222	debugfs_remove(attr->dentries.stacktrace_depth_file);
	223	attr->dentries.stacktrace_depth_file = NULL;
	224
	225	debugfs_remove(attr->dentries.require_start_file);
	226	attr->dentries.require_start_file = NULL;
	227
	228	debugfs_remove(attr->dentries.require_end_file);
	229	attr->dentries.require_end_file = NULL;
	230
	231	debugfs_remove(attr->dentries.reject_start_file);
	232	attr->dentries.reject_start_file = NULL;
	233
	234	debugfs_remove(attr->dentries.reject_end_file);
	235	attr->dentries.reject_end_file = NULL;
	236
1df49008 AM	237	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	238
6ff1cb35 AM	239	if (attr->dentries.dir)
	240	WARN_ON(!simple_empty(attr->dentries.dir));
	241
	242	debugfs_remove(attr->dentries.dir);
	243	attr->dentries.dir = NULL;
	244	}
	245
	246	int init_fault_attr_dentries(struct fault_attr attr, const char name)
	247	{
	248	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	249	struct dentry *dir;
	250
	251	memset(&attr->dentries, 0, sizeof(attr->dentries));
	252
	253	dir = debugfs_create_dir(name, NULL);
	254	if (!dir)
	255	goto fail;
	256	attr->dentries.dir = dir;
	257
	258	attr->dentries.probability_file =
	259	debugfs_create_ul("probability", mode, dir, &attr->probability);
	260
	261	attr->dentries.interval_file =
	262	debugfs_create_ul("interval", mode, dir, &attr->interval);
	263
	264	attr->dentries.times_file =
	265	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	266
	267	attr->dentries.space_file =
	268	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	269
	270	attr->dentries.verbose_file =
	271	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	272
f4f154fd AM	273	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
	274	mode, dir, &attr->task_filter);
	275
1df49008 AM	276	if (!attr->dentries.probability_file \|\| !attr->dentries.interval_file \|\|
	277	!attr->dentries.times_file \|\| !attr->dentries.space_file \|\|
	278	!attr->dentries.verbose_file \|\| !attr->dentries.task_filter_file)
	279	goto fail;
	280
	281	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	282
329409ae	283	attr->dentries.stacktrace_depth_file =
a124c28e DM	284	debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
a124c28e DM	285	"stacktrace-depth", mode, dir, &attr->stacktrace_depth);
329409ae AM	286
	287	attr->dentries.require_start_file =
	288	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
	289
	290	attr->dentries.require_end_file =
	291	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
	292
	293	attr->dentries.reject_start_file =
	294	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
	295
	296	attr->dentries.reject_end_file =
	297	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
	298
1df49008 AM	299	if (!attr->dentries.stacktrace_depth_file \|\|
	300	!attr->dentries.require_start_file \|\|
	301	!attr->dentries.require_end_file \|\|
	302	!attr->dentries.reject_start_file \|\|
	303	!attr->dentries.reject_end_file)
6ff1cb35 AM	304	goto fail;
6ff1cb35 AM	305
1df49008 AM	306	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	307
6ff1cb35 AM	308	return 0;
	309	fail:
	310	cleanup_fault_attr_dentries(attr);
	311	return -ENOMEM;
	312	}
	313
	314	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */