[mirror_ubuntu-zesty-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;

	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 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	74	trace.skip = 1;
329409ae	75
ab1b6f03	76	save_stack_trace(&trace);
329409ae AM	77	for (n = 0; n < trace.nr_entries; n++) {
	78	if (attr->reject_start <= entries[n] &&
	79	entries[n] < attr->reject_end)
08b3df2d	80	return false;
329409ae AM	81	if (attr->require_start <= entries[n] &&
329409ae AM	82	entries[n] < attr->require_end)
08b3df2d	83	found = true;
329409ae AM	84	}
	85	return found;
	86	}
	87
	88	#else
	89
08b3df2d	90	static inline bool fail_stacktrace(struct fault_attr *attr)
329409ae	91	{
1df49008	92	return true;
329409ae AM	93	}
329409ae AM	94
1df49008	95	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
329409ae	96
6ff1cb35 AM	97	/*
	98	* This code is stolen from failmalloc-1.0
	99	* http://www.nongnu.org/failmalloc/
	100	*/
	101
08b3df2d	102	bool should_fail(struct fault_attr *attr, ssize_t size)
6ff1cb35	103	{
f4f154fd	104	if (attr->task_filter && !fail_task(attr, current))
08b3df2d	105	return false;
f4f154fd	106
6ff1cb35	107	if (atomic_read(&attr->times) == 0)
08b3df2d	108	return false;
6ff1cb35 AM	109
	110	if (atomic_read(&attr->space) > size) {
	111	atomic_sub(size, &attr->space);
08b3df2d	112	return false;
6ff1cb35 AM	113	}
	114
	115	if (attr->interval > 1) {
	116	attr->count++;
	117	if (attr->count % attr->interval)
08b3df2d	118	return false;
6ff1cb35 AM	119	}
6ff1cb35 AM	120
f1729c28 DM	121	if (attr->probability <= random32() % 100)
f1729c28 DM	122	return false;
6ff1cb35	123
f1729c28 DM	124	if (!fail_stacktrace(attr))
f1729c28 DM	125	return false;
6ff1cb35	126
6ff1cb35 AM	127	fail_dump(attr);
	128
	129	if (atomic_read(&attr->times) != -1)
	130	atomic_dec_not_zero(&attr->times);
	131
08b3df2d	132	return true;
6ff1cb35 AM	133	}
	134
	135	#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
	136
	137	static void debugfs_ul_set(void *data, u64 val)
	138	{
	139	(unsigned long )data = val;
	140	}
	141
a124c28e DM	142	static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
	143	{
	144	(unsigned long )data =
	145	val < MAX_STACK_TRACE_DEPTH ?
	146	val : MAX_STACK_TRACE_DEPTH;
	147	}
	148
6ff1cb35 AM	149	static u64 debugfs_ul_get(void *data)
	150	{
	151	return (unsigned long )data;
	152	}
	153
	154	DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
	155
	156	static struct dentry debugfs_create_ul(const char name, mode_t mode,
	157	struct dentry parent, unsigned long value)
	158	{
	159	return debugfs_create_file(name, mode, parent, value, &fops_ul);
	160	}
	161
a124c28e DM	162	DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
	163	debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
	164
	165	static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
	166	const char *name, mode_t mode,
	167	struct dentry parent, unsigned long value)
	168	{
	169	return debugfs_create_file(name, mode, parent, value,
	170	&fops_ul_MAX_STACK_TRACE_DEPTH);
	171	}
	172
6ff1cb35 AM	173	static void debugfs_atomic_t_set(void *data, u64 val)
	174	{
	175	atomic_set((atomic_t *)data, val);
	176	}
	177
	178	static u64 debugfs_atomic_t_get(void *data)
	179	{
	180	return atomic_read((atomic_t *)data);
	181	}
	182
	183	DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
	184	debugfs_atomic_t_set, "%lld\n");
	185
	186	static struct dentry debugfs_create_atomic_t(const char name, mode_t mode,
	187	struct dentry parent, atomic_t value)
	188	{
	189	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
	190	}
	191
	192	void cleanup_fault_attr_dentries(struct fault_attr *attr)
	193	{
	194	debugfs_remove(attr->dentries.probability_file);
	195	attr->dentries.probability_file = NULL;
	196
	197	debugfs_remove(attr->dentries.interval_file);
	198	attr->dentries.interval_file = NULL;
	199
	200	debugfs_remove(attr->dentries.times_file);
	201	attr->dentries.times_file = NULL;
	202
	203	debugfs_remove(attr->dentries.space_file);
	204	attr->dentries.space_file = NULL;
	205
	206	debugfs_remove(attr->dentries.verbose_file);
	207	attr->dentries.verbose_file = NULL;
	208
f4f154fd AM	209	debugfs_remove(attr->dentries.task_filter_file);
	210	attr->dentries.task_filter_file = NULL;
	211
1df49008 AM	212	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
1df49008 AM	213
329409ae AM	214	debugfs_remove(attr->dentries.stacktrace_depth_file);
	215	attr->dentries.stacktrace_depth_file = NULL;
	216
	217	debugfs_remove(attr->dentries.require_start_file);
	218	attr->dentries.require_start_file = NULL;
	219
	220	debugfs_remove(attr->dentries.require_end_file);
	221	attr->dentries.require_end_file = NULL;
	222
	223	debugfs_remove(attr->dentries.reject_start_file);
	224	attr->dentries.reject_start_file = NULL;
	225
	226	debugfs_remove(attr->dentries.reject_end_file);
	227	attr->dentries.reject_end_file = NULL;
	228
1df49008 AM	229	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	230
6ff1cb35 AM	231	if (attr->dentries.dir)
	232	WARN_ON(!simple_empty(attr->dentries.dir));
	233
	234	debugfs_remove(attr->dentries.dir);
	235	attr->dentries.dir = NULL;
	236	}
	237
	238	int init_fault_attr_dentries(struct fault_attr attr, const char name)
	239	{
	240	mode_t mode = S_IFREG \| S_IRUSR \| S_IWUSR;
	241	struct dentry *dir;
	242
	243	memset(&attr->dentries, 0, sizeof(attr->dentries));
	244
	245	dir = debugfs_create_dir(name, NULL);
	246	if (!dir)
	247	goto fail;
	248	attr->dentries.dir = dir;
	249
	250	attr->dentries.probability_file =
	251	debugfs_create_ul("probability", mode, dir, &attr->probability);
	252
	253	attr->dentries.interval_file =
	254	debugfs_create_ul("interval", mode, dir, &attr->interval);
	255
	256	attr->dentries.times_file =
	257	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	258
	259	attr->dentries.space_file =
	260	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	261
	262	attr->dentries.verbose_file =
	263	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	264
f4f154fd AM	265	attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
	266	mode, dir, &attr->task_filter);
	267
1df49008 AM	268	if (!attr->dentries.probability_file \|\| !attr->dentries.interval_file \|\|
	269	!attr->dentries.times_file \|\| !attr->dentries.space_file \|\|
	270	!attr->dentries.verbose_file \|\| !attr->dentries.task_filter_file)
	271	goto fail;
	272
	273	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	274
329409ae	275	attr->dentries.stacktrace_depth_file =
a124c28e DM	276	debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
a124c28e DM	277	"stacktrace-depth", mode, dir, &attr->stacktrace_depth);
329409ae AM	278
	279	attr->dentries.require_start_file =
	280	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
	281
	282	attr->dentries.require_end_file =
	283	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
	284
	285	attr->dentries.reject_start_file =
	286	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
	287
	288	attr->dentries.reject_end_file =
	289	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
	290
1df49008 AM	291	if (!attr->dentries.stacktrace_depth_file \|\|
	292	!attr->dentries.require_start_file \|\|
	293	!attr->dentries.require_end_file \|\|
	294	!attr->dentries.reject_start_file \|\|
	295	!attr->dentries.reject_end_file)
6ff1cb35 AM	296	goto fail;
6ff1cb35 AM	297
1df49008 AM	298	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
1df49008 AM	299
6ff1cb35 AM	300	return 0;
	301	fail:
	302	cleanup_fault_attr_dentries(attr);
	303	return -ENOMEM;
	304	}
	305
	306	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */