[linux-2.6-block.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/unwind.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;
}

#ifdef CONFIG_STACK_UNWIND

static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
						void *arg)
{
	int depth;
	struct fault_attr *attr = arg;
	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);

	for (depth = 0; depth < attr->stacktrace_depth
			&& unwind(info) == 0 && UNW_PC(info); depth++) {
		if (arch_unw_user_mode(info))
			break;
		if (attr->reject_start <= UNW_PC(info) &&
			       UNW_PC(info) < attr->reject_end)
			return false;
		if (attr->require_start <= UNW_PC(info) &&
			       UNW_PC(info) < attr->require_end)
			found = true;
	}
	return found;
}

static bool fail_stacktrace(struct fault_attr *attr)
{
	struct unwind_frame_info info;

	return unwind_init_running(&info, fail_stacktrace_callback, attr);
}

#elif defined(CONFIG_STACKTRACE)

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 < MAX_STACK_TRACE_DEPTH) ?
				depth : MAX_STACK_TRACE_DEPTH;
	trace.skip = 1;
	trace.all_contexts = 0;

	save_stack_trace(&trace, NULL);
	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)
{
	static bool firsttime = true;

	if (firsttime) {
		printk(KERN_WARNING
		"This architecture does not implement save_stack_trace()\n");
		firsttime = false;
	}
	return false;
}

#endif

/*
 * 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 (!fail_stacktrace(attr))
		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)
		goto fail;

	return false;

fail:
	fail_dump(attr);

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

	return true;
}

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

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

static u64 debugfs_ul_get(void *data)
{
	return *(unsigned long *)data;
}

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);
}

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

static u64 debugfs_atomic_t_get(void *data)
{
	return atomic_read((atomic_t *)data);
}

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;

	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;

	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);

	attr->dentries.stacktrace_depth_file =
		debugfs_create_ul("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.probability_file || !attr->dentries.interval_file
	    || !attr->dentries.times_file || !attr->dentries.space_file
	    || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
	    || !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;

	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/unwind.h>
	10	#include <linux/stacktrace.h>
	11	#include <linux/kallsyms.h>
6ff1cb35 AM	12	#include <linux/fault-inject.h>
	13
	14	/*
	15	* setup_fault_attr() is a helper function for various __setup handlers, so it
	16	* returns 0 on error, because that is what __setup handlers do.
	17	*/
	18	int __init setup_fault_attr(struct fault_attr attr, char str)
	19	{
	20	unsigned long probability;
	21	unsigned long interval;
	22	int times;
	23	int space;
	24
	25	/* "<interval>,<probability>,<space>,<times>" */
	26	if (sscanf(str, "%lu,%lu,%d,%d",
	27	&interval, &probability, &space, &times) < 4) {
	28	printk(KERN_WARNING
	29	"FAULT_INJECTION: failed to parse arguments\n");
	30	return 0;
	31	}
	32
	33	attr->probability = probability;
	34	attr->interval = interval;
	35	atomic_set(&attr->times, times);
	36	atomic_set(&attr->space, space);
	37
	38	return 1;
	39	}
	40
	41	static void fail_dump(struct fault_attr *attr)
	42	{
	43	if (attr->verbose > 0)
	44	printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
	45	if (attr->verbose > 1)
	46	dump_stack();
	47	}
	48
	49	#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
	50
08b3df2d	51	static bool fail_task(struct fault_attr attr, struct task_struct task)
f4f154fd AM	52	{
	53	return !in_interrupt() && task->make_it_fail;
	54	}
	55
329409ae AM	56	#ifdef CONFIG_STACK_UNWIND
	57
	58	static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
	59	void *arg)
	60	{
	61	int depth;
	62	struct fault_attr *attr = arg;
	63	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	64
	65	for (depth = 0; depth < attr->stacktrace_depth
	66	&& unwind(info) == 0 && UNW_PC(info); depth++) {
	67	if (arch_unw_user_mode(info))
	68	break;
	69	if (attr->reject_start <= UNW_PC(info) &&
	70	UNW_PC(info) < attr->reject_end)
08b3df2d	71	return false;
329409ae AM	72	if (attr->require_start <= UNW_PC(info) &&
329409ae AM	73	UNW_PC(info) < attr->require_end)
08b3df2d	74	found = true;
329409ae AM	75	}
	76	return found;
	77	}
	78
08b3df2d	79	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	80	{
	81	struct unwind_frame_info info;
	82
	83	return unwind_init_running(&info, fail_stacktrace_callback, attr);
	84	}
	85
	86	#elif defined(CONFIG_STACKTRACE)
	87
08b3df2d	88	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	89	{
	90	struct stack_trace trace;
	91	int depth = attr->stacktrace_depth;
	92	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	93	int n;
	94	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	95
	96	if (depth == 0)
	97	return found;
	98
	99	trace.nr_entries = 0;
	100	trace.entries = entries;
	101	trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ?
	102	depth : MAX_STACK_TRACE_DEPTH;
	103	trace.skip = 1;
	104	trace.all_contexts = 0;
	105
	106	save_stack_trace(&trace, NULL);
	107	for (n = 0; n < trace.nr_entries; n++) {
	108	if (attr->reject_start <= entries[n] &&
	109	entries[n] < attr->reject_end)
08b3df2d	110	return false;
329409ae AM	111	if (attr->require_start <= entries[n] &&
329409ae AM	112	entries[n] < attr->require_end)
08b3df2d	113	found = true;
329409ae AM	114	}
	115	return found;
	116	}
	117
	118	#else
	119
08b3df2d	120	static inline bool fail_stacktrace(struct fault_attr *attr)
329409ae	121	{
08b3df2d	122	static bool firsttime = true;
329409ae AM	123
	124	if (firsttime) {
	125	printk(KERN_WARNING
	126	"This architecture does not implement save_stack_trace()\n");
08b3df2d	127	firsttime = false;
329409ae	128	}
08b3df2d	129	return false;
329409ae AM	130	}
	131
	132	#endif
	133
6ff1cb35 AM	134	/*
	135	* This code is stolen from failmalloc-1.0
	136	* http://www.nongnu.org/failmalloc/
	137	*/
	138
08b3df2d	139	bool should_fail(struct fault_attr *attr, ssize_t size)
6ff1cb35	140	{
f4f154fd	141	if (attr->task_filter && !fail_task(attr, current))
08b3df2d	142	return false;
f4f154fd	143
329409ae	144	if (!fail_stacktrace(attr))
08b3df2d	145	return false;
329409ae	146
6ff1cb35	147	if (atomic_read(&attr->times) == 0)
08b3df2d	148	return false;
6ff1cb35 AM	149
	150	if (atomic_read(&attr->space) > size) {
	151	atomic_sub(size, &attr->space);
08b3df2d	152	return false;
6ff1cb35 AM	153	}
	154
	155	if (attr->interval > 1) {
	156	attr->count++;
	157	if (attr->count % attr->interval)
08b3df2d	158	return false;
6ff1cb35 AM	159	}
	160
	161	if (attr->probability > random32() % 100)
	162	goto fail;
	163
08b3df2d	164	return false;
6ff1cb35 AM	165
	166	fail:
	167	fail_dump(attr);
	168
	169	if (atomic_read(&attr->times) != -1)
	170	atomic_dec_not_zero(&attr->times);
	171
08b3df2d	172	return true;
6ff1cb35 AM	173	}
	174
	175	#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	176
	177	static void debugfs_ul_set(void *data, u64 val)
	178	{
	179	(unsigned long )data = val;
	180	}
	181
	182	static u64 debugfs_ul_get(void *data)
	183	{
	184	return (unsigned long )data;
	185	}
	186
	187	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	188
	189	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	190	struct dentry parent, unsigned long value)
	191	{
	192	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	193	}
	194
	195	static void debugfs_atomic_t_set(void *data, u64 val)
	196	{
	197	atomic_set((atomic_t *)data, val);
	198	}
	199
	200	static u64 debugfs_atomic_t_get(void *data)
	201	{
	202	return atomic_read((atomic_t *)data);
	203	}
	204
	205	DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
	206	debugfs_atomic_t_set, "%lld\n");
	207
	208	static struct dentry debugfs_create_atomic_t(const char name, mode_t mode,
	209	struct dentry parent, atomic_t value)
	210	{
	211	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
	212	}
	213
	214	void cleanup_fault_attr_dentries(struct fault_attr *attr)
	215	{
	216	debugfs_remove(attr->dentries.probability_file);
	217	attr->dentries.probability_file = NULL;
	218
	219	debugfs_remove(attr->dentries.interval_file);
	220	attr->dentries.interval_file = NULL;
	221
	222	debugfs_remove(attr->dentries.times_file);
	223	attr->dentries.times_file = NULL;
	224
	225	debugfs_remove(attr->dentries.space_file);
	226	attr->dentries.space_file = NULL;
	227
	228	debugfs_remove(attr->dentries.verbose_file);
	229	attr->dentries.verbose_file = NULL;
	230
f4f154fd AM	231	debugfs_remove(attr->dentries.task_filter_file);
	232	attr->dentries.task_filter_file = NULL;
	233
329409ae AM	234	debugfs_remove(attr->dentries.stacktrace_depth_file);
	235	attr->dentries.stacktrace_depth_file = NULL;
	236
	237	debugfs_remove(attr->dentries.require_start_file);
	238	attr->dentries.require_start_file = NULL;
	239
	240	debugfs_remove(attr->dentries.require_end_file);
	241	attr->dentries.require_end_file = NULL;
	242
	243	debugfs_remove(attr->dentries.reject_start_file);
	244	attr->dentries.reject_start_file = NULL;
	245
	246	debugfs_remove(attr->dentries.reject_end_file);
	247	attr->dentries.reject_end_file = NULL;
	248
6ff1cb35 AM	249	if (attr->dentries.dir)
	250	WARN_ON(!simple_empty(attr->dentries.dir));
	251
	252	debugfs_remove(attr->dentries.dir);
	253	attr->dentries.dir = NULL;
	254	}
	255
	256	int init_fault_attr_dentries(struct fault_attr attr, const char name)
	257	{
	258	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	259	struct dentry *dir;
	260
	261	memset(&attr->dentries, 0, sizeof(attr->dentries));
	262
	263	dir = debugfs_create_dir(name, NULL);
	264	if (!dir)
	265	goto fail;
	266	attr->dentries.dir = dir;
	267
	268	attr->dentries.probability_file =
	269	debugfs_create_ul("probability", mode, dir, &attr->probability);
	270
	271	attr->dentries.interval_file =
	272	debugfs_create_ul("interval", mode, dir, &attr->interval);
	273
	274	attr->dentries.times_file =
	275	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	276
	277	attr->dentries.space_file =
	278	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	279
	280	attr->dentries.verbose_file =
	281	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	282
f4f154fd AM	283	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
	284	mode, dir, &attr->task_filter);
	285
329409ae AM	286	attr->dentries.stacktrace_depth_file =
	287	debugfs_create_ul("stacktrace-depth", mode, dir,
	288	&attr->stacktrace_depth);
	289
	290	attr->dentries.require_start_file =
	291	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
	292
	293	attr->dentries.require_end_file =
	294	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
	295
	296	attr->dentries.reject_start_file =
	297	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
	298
	299	attr->dentries.reject_end_file =
	300	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
	301
	302
6ff1cb35 AM	303	if (!attr->dentries.probability_file \|\| !attr->dentries.interval_file
6ff1cb35 AM	304	\|\| !attr->dentries.times_file \|\| !attr->dentries.space_file
329409ae AM	305	\|\| !attr->dentries.verbose_file \|\| !attr->dentries.task_filter_file
	306	\|\| !attr->dentries.stacktrace_depth_file
	307	\|\| !attr->dentries.require_start_file
	308	\|\| !attr->dentries.require_end_file
	309	\|\| !attr->dentries.reject_start_file
	310	\|\| !attr->dentries.reject_end_file
	311	)
6ff1cb35 AM	312	goto fail;
	313
	314	return 0;
	315	fail:
	316	cleanup_fault_attr_dentries(attr);
	317	return -ENOMEM;
	318	}
	319
	320	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */