[mirror_ubuntu-artful-kernel.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;
}

#define MAX_STACK_TRACE_DEPTH 32

#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;
	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 void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
{
	*(unsigned long *)data =
		val < MAX_STACK_TRACE_DEPTH ?
		val : MAX_STACK_TRACE_DEPTH;
}

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);
}

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);
}

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_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.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
a124c28e DM	56	#define MAX_STACK_TRACE_DEPTH 32
a124c28e DM	57
329409ae AM	58	#ifdef CONFIG_STACK_UNWIND
	59
	60	static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
	61	void *arg)
	62	{
	63	int depth;
	64	struct fault_attr *attr = arg;
	65	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	66
	67	for (depth = 0; depth < attr->stacktrace_depth
	68	&& unwind(info) == 0 && UNW_PC(info); depth++) {
	69	if (arch_unw_user_mode(info))
	70	break;
	71	if (attr->reject_start <= UNW_PC(info) &&
	72	UNW_PC(info) < attr->reject_end)
08b3df2d	73	return false;
329409ae AM	74	if (attr->require_start <= UNW_PC(info) &&
329409ae AM	75	UNW_PC(info) < attr->require_end)
08b3df2d	76	found = true;
329409ae AM	77	}
	78	return found;
	79	}
	80
08b3df2d	81	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	82	{
	83	struct unwind_frame_info info;
	84
	85	return unwind_init_running(&info, fail_stacktrace_callback, attr);
	86	}
	87
	88	#elif defined(CONFIG_STACKTRACE)
	89
08b3df2d	90	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	91	{
	92	struct stack_trace trace;
	93	int depth = attr->stacktrace_depth;
	94	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	95	int n;
	96	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	97
	98	if (depth == 0)
	99	return found;
	100
	101	trace.nr_entries = 0;
	102	trace.entries = entries;
a124c28e	103	trace.max_entries = depth;
329409ae AM	104	trace.skip = 1;
	105	trace.all_contexts = 0;
	106
	107	save_stack_trace(&trace, NULL);
	108	for (n = 0; n < trace.nr_entries; n++) {
	109	if (attr->reject_start <= entries[n] &&
	110	entries[n] < attr->reject_end)
08b3df2d	111	return false;
329409ae AM	112	if (attr->require_start <= entries[n] &&
329409ae AM	113	entries[n] < attr->require_end)
08b3df2d	114	found = true;
329409ae AM	115	}
	116	return found;
	117	}
	118
	119	#else
	120
08b3df2d	121	static inline bool fail_stacktrace(struct fault_attr *attr)
329409ae	122	{
08b3df2d	123	static bool firsttime = true;
329409ae AM	124
	125	if (firsttime) {
	126	printk(KERN_WARNING
	127	"This architecture does not implement save_stack_trace()\n");
08b3df2d	128	firsttime = false;
329409ae	129	}
08b3df2d	130	return false;
329409ae AM	131	}
	132
	133	#endif
	134
6ff1cb35 AM	135	/*
	136	* This code is stolen from failmalloc-1.0
	137	* http://www.nongnu.org/failmalloc/
	138	*/
	139
08b3df2d	140	bool should_fail(struct fault_attr *attr, ssize_t size)
6ff1cb35	141	{
f4f154fd	142	if (attr->task_filter && !fail_task(attr, current))
08b3df2d	143	return false;
f4f154fd	144
329409ae	145	if (!fail_stacktrace(attr))
08b3df2d	146	return false;
329409ae	147
6ff1cb35	148	if (atomic_read(&attr->times) == 0)
08b3df2d	149	return false;
6ff1cb35 AM	150
	151	if (atomic_read(&attr->space) > size) {
	152	atomic_sub(size, &attr->space);
08b3df2d	153	return false;
6ff1cb35 AM	154	}
	155
	156	if (attr->interval > 1) {
	157	attr->count++;
	158	if (attr->count % attr->interval)
08b3df2d	159	return false;
6ff1cb35 AM	160	}
	161
	162	if (attr->probability > random32() % 100)
	163	goto fail;
	164
08b3df2d	165	return false;
6ff1cb35 AM	166
	167	fail:
	168	fail_dump(attr);
	169
	170	if (atomic_read(&attr->times) != -1)
	171	atomic_dec_not_zero(&attr->times);
	172
08b3df2d	173	return true;
6ff1cb35 AM	174	}
	175
	176	#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	177
	178	static void debugfs_ul_set(void *data, u64 val)
	179	{
	180	(unsigned long )data = val;
	181	}
	182
a124c28e DM	183	static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
	184	{
	185	(unsigned long )data =
	186	val < MAX_STACK_TRACE_DEPTH ?
	187	val : MAX_STACK_TRACE_DEPTH;
	188	}
	189
6ff1cb35 AM	190	static u64 debugfs_ul_get(void *data)
	191	{
	192	return (unsigned long )data;
	193	}
	194
	195	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	196
	197	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	198	struct dentry parent, unsigned long value)
	199	{
	200	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	201	}
	202
a124c28e DM	203	DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
	204	debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
	205
	206	static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
	207	const char *name, mode_t mode,
	208	struct dentry parent, unsigned long value)
	209	{
	210	return debugfs_create_file(name, mode, parent, value,
	211	&fops_ul_MAX_STACK_TRACE_DEPTH);
	212	}
	213
6ff1cb35 AM	214	static void debugfs_atomic_t_set(void *data, u64 val)
	215	{
	216	atomic_set((atomic_t *)data, val);
	217	}
	218
	219	static u64 debugfs_atomic_t_get(void *data)
	220	{
	221	return atomic_read((atomic_t *)data);
	222	}
	223
	224	DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
	225	debugfs_atomic_t_set, "%lld\n");
	226
	227	static struct dentry debugfs_create_atomic_t(const char name, mode_t mode,
	228	struct dentry parent, atomic_t value)
	229	{
	230	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
	231	}
	232
	233	void cleanup_fault_attr_dentries(struct fault_attr *attr)
	234	{
	235	debugfs_remove(attr->dentries.probability_file);
	236	attr->dentries.probability_file = NULL;
	237
	238	debugfs_remove(attr->dentries.interval_file);
	239	attr->dentries.interval_file = NULL;
	240
	241	debugfs_remove(attr->dentries.times_file);
	242	attr->dentries.times_file = NULL;
	243
	244	debugfs_remove(attr->dentries.space_file);
	245	attr->dentries.space_file = NULL;
	246
	247	debugfs_remove(attr->dentries.verbose_file);
	248	attr->dentries.verbose_file = NULL;
	249
f4f154fd AM	250	debugfs_remove(attr->dentries.task_filter_file);
	251	attr->dentries.task_filter_file = NULL;
	252
329409ae AM	253	debugfs_remove(attr->dentries.stacktrace_depth_file);
	254	attr->dentries.stacktrace_depth_file = NULL;
	255
	256	debugfs_remove(attr->dentries.require_start_file);
	257	attr->dentries.require_start_file = NULL;
	258
	259	debugfs_remove(attr->dentries.require_end_file);
	260	attr->dentries.require_end_file = NULL;
	261
	262	debugfs_remove(attr->dentries.reject_start_file);
	263	attr->dentries.reject_start_file = NULL;
	264
	265	debugfs_remove(attr->dentries.reject_end_file);
	266	attr->dentries.reject_end_file = NULL;
	267
6ff1cb35 AM	268	if (attr->dentries.dir)
	269	WARN_ON(!simple_empty(attr->dentries.dir));
	270
	271	debugfs_remove(attr->dentries.dir);
	272	attr->dentries.dir = NULL;
	273	}
	274
	275	int init_fault_attr_dentries(struct fault_attr attr, const char name)
	276	{
	277	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	278	struct dentry *dir;
	279
	280	memset(&attr->dentries, 0, sizeof(attr->dentries));
	281
	282	dir = debugfs_create_dir(name, NULL);
	283	if (!dir)
	284	goto fail;
	285	attr->dentries.dir = dir;
	286
	287	attr->dentries.probability_file =
	288	debugfs_create_ul("probability", mode, dir, &attr->probability);
	289
	290	attr->dentries.interval_file =
	291	debugfs_create_ul("interval", mode, dir, &attr->interval);
	292
	293	attr->dentries.times_file =
	294	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	295
	296	attr->dentries.space_file =
	297	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	298
	299	attr->dentries.verbose_file =
	300	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	301
f4f154fd AM	302	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
	303	mode, dir, &attr->task_filter);
	304
329409ae	305	attr->dentries.stacktrace_depth_file =
a124c28e DM	306	debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
a124c28e DM	307	"stacktrace-depth", mode, dir, &attr->stacktrace_depth);
329409ae AM	308
	309	attr->dentries.require_start_file =
	310	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
	311
	312	attr->dentries.require_end_file =
	313	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
	314
	315	attr->dentries.reject_start_file =
	316	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
	317
	318	attr->dentries.reject_end_file =
	319	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
	320
	321
6ff1cb35 AM	322	if (!attr->dentries.probability_file \|\| !attr->dentries.interval_file
6ff1cb35 AM	323	\|\| !attr->dentries.times_file \|\| !attr->dentries.space_file
329409ae AM	324	\|\| !attr->dentries.verbose_file \|\| !attr->dentries.task_filter_file
	325	\|\| !attr->dentries.stacktrace_depth_file
	326	\|\| !attr->dentries.require_start_file
	327	\|\| !attr->dentries.require_end_file
	328	\|\| !attr->dentries.reject_start_file
	329	\|\| !attr->dentries.reject_end_file
	330	)
6ff1cb35 AM	331	goto fail;
	332
	333	return 0;
	334	fail:
	335	cleanup_fault_attr_dentries(attr);
	336	return -ENOMEM;
	337	}
	338
	339	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */