[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_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;
	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)
{
	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 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;

#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/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
1df49008	58	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
329409ae	59
08b3df2d	60	static bool fail_stacktrace(struct fault_attr *attr)
329409ae AM	61	{
	62	struct stack_trace trace;
	63	int depth = attr->stacktrace_depth;
	64	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	65	int n;
	66	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
	67
	68	if (depth == 0)
	69	return found;
	70
	71	trace.nr_entries = 0;
	72	trace.entries = entries;
a124c28e	73	trace.max_entries = depth;
329409ae AM	74	trace.skip = 1;
	75	trace.all_contexts = 0;
	76
	77	save_stack_trace(&trace, NULL);
	78	for (n = 0; n < trace.nr_entries; n++) {
	79	if (attr->reject_start <= entries[n] &&
	80	entries[n] < attr->reject_end)
08b3df2d	81	return false;
329409ae AM	82	if (attr->require_start <= entries[n] &&
329409ae AM	83	entries[n] < attr->require_end)
08b3df2d	84	found = true;
329409ae AM	85	}
	86	return found;
	87	}
	88
	89	#else
	90
08b3df2d	91	static inline bool fail_stacktrace(struct fault_attr *attr)
329409ae	92	{
1df49008	93	return true;
329409ae AM	94	}
329409ae AM	95
1df49008	96	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
329409ae	97
6ff1cb35 AM	98	/*
	99	* This code is stolen from failmalloc-1.0
	100	* http://www.nongnu.org/failmalloc/
	101	*/
	102
08b3df2d	103	bool should_fail(struct fault_attr *attr, ssize_t size)
6ff1cb35	104	{
f4f154fd	105	if (attr->task_filter && !fail_task(attr, current))
08b3df2d	106	return false;
f4f154fd	107
6ff1cb35	108	if (atomic_read(&attr->times) == 0)
08b3df2d	109	return false;
6ff1cb35 AM	110
	111	if (atomic_read(&attr->space) > size) {
	112	atomic_sub(size, &attr->space);
08b3df2d	113	return false;
6ff1cb35 AM	114	}
	115
	116	if (attr->interval > 1) {
	117	attr->count++;
	118	if (attr->count % attr->interval)
08b3df2d	119	return false;
6ff1cb35 AM	120	}
6ff1cb35 AM	121
f1729c28 DM	122	if (attr->probability <= random32() % 100)
f1729c28 DM	123	return false;
6ff1cb35	124
f1729c28 DM	125	if (!fail_stacktrace(attr))
f1729c28 DM	126	return false;
6ff1cb35	127
6ff1cb35 AM	128	fail_dump(attr);
	129
	130	if (atomic_read(&attr->times) != -1)
	131	atomic_dec_not_zero(&attr->times);
	132
08b3df2d	133	return true;
6ff1cb35 AM	134	}
	135
	136	#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	137
	138	static void debugfs_ul_set(void *data, u64 val)
	139	{
	140	(unsigned long )data = val;
	141	}
	142
a124c28e DM	143	static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
	144	{
	145	(unsigned long )data =
	146	val < MAX_STACK_TRACE_DEPTH ?
	147	val : MAX_STACK_TRACE_DEPTH;
	148	}
	149
6ff1cb35 AM	150	static u64 debugfs_ul_get(void *data)
	151	{
	152	return (unsigned long )data;
	153	}
	154
	155	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	156
	157	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	158	struct dentry parent, unsigned long value)
	159	{
	160	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	161	}
	162
a124c28e DM	163	DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
	164	debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
	165
	166	static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
	167	const char *name, mode_t mode,
	168	struct dentry parent, unsigned long value)
	169	{
	170	return debugfs_create_file(name, mode, parent, value,
	171	&fops_ul_MAX_STACK_TRACE_DEPTH);
	172	}
	173
6ff1cb35 AM	174	static void debugfs_atomic_t_set(void *data, u64 val)
	175	{
	176	atomic_set((atomic_t *)data, val);
	177	}
	178
	179	static u64 debugfs_atomic_t_get(void *data)
	180	{
	181	return atomic_read((atomic_t *)data);
	182	}
	183
	184	DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
	185	debugfs_atomic_t_set, "%lld\n");
	186
	187	static struct dentry debugfs_create_atomic_t(const char name, mode_t mode,
	188	struct dentry parent, atomic_t value)
	189	{
	190	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
	191	}
	192
	193	void cleanup_fault_attr_dentries(struct fault_attr *attr)
	194	{
	195	debugfs_remove(attr->dentries.probability_file);
	196	attr->dentries.probability_file = NULL;
	197
	198	debugfs_remove(attr->dentries.interval_file);
	199	attr->dentries.interval_file = NULL;
	200
	201	debugfs_remove(attr->dentries.times_file);
	202	attr->dentries.times_file = NULL;
	203
	204	debugfs_remove(attr->dentries.space_file);
	205	attr->dentries.space_file = NULL;
	206
	207	debugfs_remove(attr->dentries.verbose_file);
	208	attr->dentries.verbose_file = NULL;
	209
f4f154fd AM	210	debugfs_remove(attr->dentries.task_filter_file);
	211	attr->dentries.task_filter_file = NULL;
	212
1df49008 AM	213	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
1df49008 AM	214
329409ae AM	215	debugfs_remove(attr->dentries.stacktrace_depth_file);
	216	attr->dentries.stacktrace_depth_file = NULL;
	217
	218	debugfs_remove(attr->dentries.require_start_file);
	219	attr->dentries.require_start_file = NULL;
	220
	221	debugfs_remove(attr->dentries.require_end_file);
	222	attr->dentries.require_end_file = NULL;
	223
	224	debugfs_remove(attr->dentries.reject_start_file);
	225	attr->dentries.reject_start_file = NULL;
	226
	227	debugfs_remove(attr->dentries.reject_end_file);
	228	attr->dentries.reject_end_file = NULL;
	229
1df49008 AM	230	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	231
6ff1cb35 AM	232	if (attr->dentries.dir)
	233	WARN_ON(!simple_empty(attr->dentries.dir));
	234
	235	debugfs_remove(attr->dentries.dir);
	236	attr->dentries.dir = NULL;
	237	}
	238
	239	int init_fault_attr_dentries(struct fault_attr attr, const char name)
	240	{
	241	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	242	struct dentry *dir;
	243
	244	memset(&attr->dentries, 0, sizeof(attr->dentries));
	245
	246	dir = debugfs_create_dir(name, NULL);
	247	if (!dir)
	248	goto fail;
	249	attr->dentries.dir = dir;
	250
	251	attr->dentries.probability_file =
	252	debugfs_create_ul("probability", mode, dir, &attr->probability);
	253
	254	attr->dentries.interval_file =
	255	debugfs_create_ul("interval", mode, dir, &attr->interval);
	256
	257	attr->dentries.times_file =
	258	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	259
	260	attr->dentries.space_file =
	261	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	262
	263	attr->dentries.verbose_file =
	264	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	265
f4f154fd AM	266	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
	267	mode, dir, &attr->task_filter);
	268
1df49008 AM	269	if (!attr->dentries.probability_file \|\| !attr->dentries.interval_file \|\|
	270	!attr->dentries.times_file \|\| !attr->dentries.space_file \|\|
	271	!attr->dentries.verbose_file \|\| !attr->dentries.task_filter_file)
	272	goto fail;
	273
	274	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	275
329409ae	276	attr->dentries.stacktrace_depth_file =
a124c28e DM	277	debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
a124c28e DM	278	"stacktrace-depth", mode, dir, &attr->stacktrace_depth);
329409ae AM	279
	280	attr->dentries.require_start_file =
	281	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
	282
	283	attr->dentries.require_end_file =
	284	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
	285
	286	attr->dentries.reject_start_file =
	287	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
	288
	289	attr->dentries.reject_end_file =
	290	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
	291
1df49008 AM	292	if (!attr->dentries.stacktrace_depth_file \|\|
	293	!attr->dentries.require_start_file \|\|
	294	!attr->dentries.require_end_file \|\|
	295	!attr->dentries.reject_start_file \|\|
	296	!attr->dentries.reject_end_file)
6ff1cb35 AM	297	goto fail;
6ff1cb35 AM	298
1df49008 AM	299	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	300
6ff1cb35 AM	301	return 0;
	302	fail:
	303	cleanup_fault_attr_dentries(attr);
	304	return -ENOMEM;
	305	}
	306
	307	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */