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

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/sched.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/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;
}

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

static int debugfs_stacktrace_depth_set(void *data, u64 val)
{
	*(unsigned long *)data =
		min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);

	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
			debugfs_stacktrace_depth_set, "%llu\n");

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

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

	dir = debugfs_create_dir(name, parent);
	if (!dir)
		return ERR_PTR(-ENOMEM);

	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
		goto fail;
	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
		goto fail;
	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
		goto fail;
	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
		goto fail;
	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
		goto fail;
	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
		goto fail;

#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
				&attr->stacktrace_depth))
		goto fail;
	if (!debugfs_create_ul("require-start", mode, dir,
				&attr->require_start))
		goto fail;
	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
		goto fail;
	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
		goto fail;
	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
		goto fail;

#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

	return dir;
fail:
	debugfs_remove_recursive(dir);

	return ERR_PTR(-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>
d43c36dc	4	#include <linux/sched.h>
6ff1cb35 AM	5	#include <linux/stat.h>
	6	#include <linux/types.h>
	7	#include <linux/fs.h>
	8	#include <linux/module.h>
f4f154fd	9	#include <linux/interrupt.h>
329409ae	10	#include <linux/stacktrace.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
8b88b099	142	static int debugfs_ul_get(void data, u64 val)
6ff1cb35	143	{
8b88b099 CH	144	val = (unsigned long *)data;
8b88b099 CH	145	return 0;
6ff1cb35 AM	146	}
	147
	148	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	149
	150	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	151	struct dentry parent, unsigned long value)
	152	{
	153	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	154	}
	155
6ddb23c7	156	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
a124c28e	157
8307fc25 AM	158	static int debugfs_stacktrace_depth_set(void *data, u64 val)
	159	{
	160	(unsigned long )data =
	161	min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
	162
	163	return 0;
	164	}
	165
	166	DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
	167	debugfs_stacktrace_depth_set, "%llu\n");
	168
	169	static struct dentry *debugfs_create_stacktrace_depth(
a124c28e DM	170	const char *name, mode_t mode,
	171	struct dentry parent, unsigned long value)
	172	{
	173	return debugfs_create_file(name, mode, parent, value,
8307fc25	174	&fops_stacktrace_depth);
a124c28e	175	}
8307fc25	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
dd48c085 AM	200	struct dentry fault_create_debugfs_attr(const char name,
dd48c085 AM	201	struct dentry parent, struct fault_attr attr)
6ff1cb35 AM	202	{
	203	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	204	struct dentry *dir;
	205
dd48c085	206	dir = debugfs_create_dir(name, parent);
6ff1cb35	207	if (!dir)
dd48c085	208	return ERR_PTR(-ENOMEM);
6ff1cb35	209
7f5ddcc8 AM	210	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
	211	goto fail;
	212	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
	213	goto fail;
	214	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
	215	goto fail;
	216	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
	217	goto fail;
	218	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
	219	goto fail;
	220	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
1df49008 AM	221	goto fail;
	222
	223	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	224
7f5ddcc8 AM	225	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
	226	&attr->stacktrace_depth))
	227	goto fail;
	228	if (!debugfs_create_ul("require-start", mode, dir,
	229	&attr->require_start))
	230	goto fail;
	231	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
	232	goto fail;
	233	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
	234	goto fail;
	235	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
6ff1cb35 AM	236	goto fail;
6ff1cb35 AM	237
1df49008 AM	238	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	239
dd48c085	240	return dir;
6ff1cb35	241	fail:
dd48c085	242	debugfs_remove_recursive(dir);
7f5ddcc8	243
dd48c085	244	return ERR_PTR(-ENOMEM);
6ff1cb35 AM	245	}
	246
	247	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */