lib/fault-inject.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 #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/export.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 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;
 }
 EXPORT_SYMBOL_GPL(setup_fault_attr);

 static void fail_dump(struct fault_attr *attr)
 {
 	if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) {
 		printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n"
 		       "name %pd, interval %lu, probability %lu, "
 		       "space %d, times %d\n", attr->dname,
 		       attr->interval, attr->probability,
 		       atomic_read(&attr->space),
 		       atomic_read(&attr->times));
 		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_task() && task->make_it_fail;
 }

 #define MAX_STACK_TRACE_DEPTH 32

 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

 static bool fail_stacktrace(struct fault_attr *attr)
 {
 	int depth = attr->stacktrace_depth;
 	unsigned long entries[MAX_STACK_TRACE_DEPTH];
 	int n, nr_entries;
 	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);

 	if (depth == 0 || (found && !attr->reject_start && !attr->reject_end))
 		return found;

 	nr_entries = stack_trace_save(entries, depth, 1);
 	for (n = 0; n < 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_ex(struct fault_attr *attr, ssize_t size, int flags)
 {
 	bool stack_checked = false;

 	if (in_task()) {
 		unsigned int fail_nth = READ_ONCE(current->fail_nth);

 		if (fail_nth) {
 			if (!fail_stacktrace(attr))
 				return false;

 			stack_checked = true;
 			fail_nth--;
 			WRITE_ONCE(current->fail_nth, fail_nth);
 			if (!fail_nth)
 				goto fail;

 			return false;
 		}
 	}

 	/* No need to check any other properties if the probability is 0 */
 	if (attr->probability == 0)
 		return false;

 	if (attr->task_filter && !fail_task(attr, current))
 		return false;

 	if (atomic_read(&attr->times) == 0)
 		return false;

 	if (!stack_checked && !fail_stacktrace(attr))
 		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 <= get_random_u32_below(100))
 		return false;

 fail:
 	if (!(flags & FAULT_NOWARN))
 		fail_dump(attr);

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

 	return true;
 }

 bool should_fail(struct fault_attr *attr, ssize_t size)
 {
 	return should_fail_ex(attr, size, 0);
 }
 EXPORT_SYMBOL_GPL(should_fail);

 #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 void debugfs_create_ul(const char *name, umode_t mode,
 			      struct dentry *parent, unsigned long *value)
 {
 	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 void debugfs_create_stacktrace_depth(const char *name, umode_t mode,
 					    struct dentry *parent,
 					    unsigned long *value)
 {
 	debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth);
 }

 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

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

 	dir = debugfs_create_dir(name, parent);
 	if (IS_ERR(dir))
 		return dir;

 	debugfs_create_ul("probability", mode, dir, &attr->probability);
 	debugfs_create_ul("interval", mode, dir, &attr->interval);
 	debugfs_create_atomic_t("times", mode, dir, &attr->times);
 	debugfs_create_atomic_t("space", mode, dir, &attr->space);
 	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
 	debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
 			   &attr->ratelimit_state.interval);
 	debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
 			   &attr->ratelimit_state.burst);
 	debugfs_create_bool("task-filter", mode, dir, &attr->task_filter);

 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 	debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
 					&attr->stacktrace_depth);
 	debugfs_create_xul("require-start", mode, dir, &attr->require_start);
 	debugfs_create_xul("require-end", mode, dir, &attr->require_end);
 	debugfs_create_xul("reject-start", mode, dir, &attr->reject_start);
 	debugfs_create_xul("reject-end", mode, dir, &attr->reject_end);
 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

 	attr->dname = dget(dir);
 	return dir;
 }
 EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);

 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

 #ifdef CONFIG_FAULT_INJECTION_CONFIGFS

 /* These configfs attribute utilities are copied from drivers/block/null_blk/main.c */

 static ssize_t fault_uint_attr_show(unsigned int val, char *page)
 {
 	return snprintf(page, PAGE_SIZE, "%u\n", val);
 }

 static ssize_t fault_ulong_attr_show(unsigned long val, char *page)
 {
 	return snprintf(page, PAGE_SIZE, "%lu\n", val);
 }

 static ssize_t fault_bool_attr_show(bool val, char *page)
 {
 	return snprintf(page, PAGE_SIZE, "%u\n", val);
 }

 static ssize_t fault_atomic_t_attr_show(atomic_t val, char *page)
 {
 	return snprintf(page, PAGE_SIZE, "%d\n", atomic_read(&val));
 }

 static ssize_t fault_uint_attr_store(unsigned int *val, const char *page, size_t count)
 {
 	unsigned int tmp;
 	int result;

 	result = kstrtouint(page, 0, &tmp);
 	if (result < 0)
 		return result;

 	*val = tmp;
 	return count;
 }

 static ssize_t fault_ulong_attr_store(unsigned long *val, const char *page, size_t count)
 {
 	int result;
 	unsigned long tmp;

 	result = kstrtoul(page, 0, &tmp);
 	if (result < 0)
 		return result;

 	*val = tmp;
 	return count;
 }

 static ssize_t fault_bool_attr_store(bool *val, const char *page, size_t count)
 {
 	bool tmp;
 	int result;

 	result = kstrtobool(page, &tmp);
 	if (result < 0)
 		return result;

 	*val = tmp;
 	return count;
 }

 static ssize_t fault_atomic_t_attr_store(atomic_t *val, const char *page, size_t count)
 {
 	int tmp;
 	int result;

 	result = kstrtoint(page, 0, &tmp);
 	if (result < 0)
 		return result;

 	atomic_set(val, tmp);
 	return count;
 }

 #define CONFIGFS_ATTR_NAMED(_pfx, _name, _attr_name)	\
 static struct configfs_attribute _pfx##attr_##_name = {	\
 	.ca_name	= _attr_name,			\
 	.ca_mode	= 0644,				\
 	.ca_owner	= THIS_MODULE,			\
 	.show		= _pfx##_name##_show,		\
 	.store		= _pfx##_name##_store,		\
 }

 static struct fault_config *to_fault_config(struct config_item *item)
 {
 	return container_of(to_config_group(item), struct fault_config, group);
 }

 #define FAULT_CONFIGFS_ATTR_NAMED(NAME, ATTR_NAME, MEMBER, TYPE)				\
 static ssize_t fault_##NAME##_show(struct config_item *item, char *page)			\
 {												\
 	return fault_##TYPE##_attr_show(to_fault_config(item)->attr.MEMBER, page);		\
 }												\
 static ssize_t fault_##NAME##_store(struct config_item *item, const char *page, size_t count)	\
 {												\
 	struct fault_config *config = to_fault_config(item);					\
 	return fault_##TYPE##_attr_store(&config->attr.MEMBER, page, count);			\
 }												\
 CONFIGFS_ATTR_NAMED(fault_, NAME, ATTR_NAME)

 #define FAULT_CONFIGFS_ATTR(NAME, TYPE)	\
 	FAULT_CONFIGFS_ATTR_NAMED(NAME, __stringify(NAME), NAME, TYPE)

 FAULT_CONFIGFS_ATTR(probability, ulong);
 FAULT_CONFIGFS_ATTR(interval, ulong);
 FAULT_CONFIGFS_ATTR(times, atomic_t);
 FAULT_CONFIGFS_ATTR(space, atomic_t);
 FAULT_CONFIGFS_ATTR(verbose, ulong);
 FAULT_CONFIGFS_ATTR_NAMED(ratelimit_interval, "verbose_ratelimit_interval_ms",
 		ratelimit_state.interval, uint);
 FAULT_CONFIGFS_ATTR_NAMED(ratelimit_burst, "verbose_ratelimit_burst",
 		ratelimit_state.burst, uint);
 FAULT_CONFIGFS_ATTR_NAMED(task_filter, "task-filter", task_filter, bool);

 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

 static ssize_t fault_stacktrace_depth_show(struct config_item *item, char *page)
 {
 	return fault_ulong_attr_show(to_fault_config(item)->attr.stacktrace_depth, page);
 }

 static ssize_t fault_stacktrace_depth_store(struct config_item *item, const char *page,
 		size_t count)
 {
 	int result;
 	unsigned long tmp;

 	result = kstrtoul(page, 0, &tmp);
 	if (result < 0)
 		return result;

 	to_fault_config(item)->attr.stacktrace_depth =
 		min_t(unsigned long, tmp, MAX_STACK_TRACE_DEPTH);

 	return count;
 }

 CONFIGFS_ATTR_NAMED(fault_, stacktrace_depth, "stacktrace-depth");

 static ssize_t fault_xul_attr_show(unsigned long val, char *page)
 {
 	return snprintf(page, PAGE_SIZE,
 			sizeof(val) == sizeof(u32) ? "0x%08lx\n" : "0x%016lx\n", val);
 }

 static ssize_t fault_xul_attr_store(unsigned long *val, const char *page, size_t count)
 {
 	return fault_ulong_attr_store(val, page, count);
 }

 FAULT_CONFIGFS_ATTR_NAMED(require_start, "require-start", require_start, xul);
 FAULT_CONFIGFS_ATTR_NAMED(require_end, "require-end", require_end, xul);
 FAULT_CONFIGFS_ATTR_NAMED(reject_start, "reject-start", reject_start, xul);
 FAULT_CONFIGFS_ATTR_NAMED(reject_end, "reject-end", reject_end, xul);

 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

 static struct configfs_attribute *fault_config_attrs[] = {
 	&fault_attr_probability,
 	&fault_attr_interval,
 	&fault_attr_times,
 	&fault_attr_space,
 	&fault_attr_verbose,
 	&fault_attr_ratelimit_interval,
 	&fault_attr_ratelimit_burst,
 	&fault_attr_task_filter,
 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 	&fault_attr_stacktrace_depth,
 	&fault_attr_require_start,
 	&fault_attr_require_end,
 	&fault_attr_reject_start,
 	&fault_attr_reject_end,
 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 	NULL,
 };

 static const struct config_item_type fault_config_type = {
 	.ct_attrs	= fault_config_attrs,
 	.ct_owner	= THIS_MODULE,
 };

 void fault_config_init(struct fault_config *config, const char *name)
 {
 	config_group_init_type_name(&config->group, name, &fault_config_type);
 }
 EXPORT_SYMBOL_GPL(fault_config_init);

 #endif /* CONFIG_FAULT_INJECTION_CONFIGFS */
	// SPDX-License-Identifier: GPL-2.0-only
	#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/export.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 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;
	}
	EXPORT_SYMBOL_GPL(setup_fault_attr);

	static void fail_dump(struct fault_attr *attr)
	{
	if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) {
	printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n"
	"name %pd, interval %lu, probability %lu, "
	"space %d, times %d\n", attr->dname,
	attr->interval, attr->probability,
	atomic_read(&attr->space),
	atomic_read(&attr->times));
	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_task() && task->make_it_fail;
	}

	#define MAX_STACK_TRACE_DEPTH 32

	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

	static bool fail_stacktrace(struct fault_attr *attr)
	{
	int depth = attr->stacktrace_depth;
	unsigned long entries[MAX_STACK_TRACE_DEPTH];
	int n, nr_entries;
	bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);

	if (depth == 0 \|\| (found && !attr->reject_start && !attr->reject_end))
	return found;

	nr_entries = stack_trace_save(entries, depth, 1);
	for (n = 0; n < 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_ex(struct fault_attr *attr, ssize_t size, int flags)
	{
	bool stack_checked = false;

	if (in_task()) {
	unsigned int fail_nth = READ_ONCE(current->fail_nth);

	if (fail_nth) {
	if (!fail_stacktrace(attr))
	return false;

	stack_checked = true;
	fail_nth--;
	WRITE_ONCE(current->fail_nth, fail_nth);
	if (!fail_nth)
	goto fail;

	return false;
	}
	}

	/* No need to check any other properties if the probability is 0 */
	if (attr->probability == 0)
	return false;

	if (attr->task_filter && !fail_task(attr, current))
	return false;

	if (atomic_read(&attr->times) == 0)
	return false;

	if (!stack_checked && !fail_stacktrace(attr))
	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 <= get_random_u32_below(100))
	return false;

	fail:
	if (!(flags & FAULT_NOWARN))
	fail_dump(attr);

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

	return true;
	}

	bool should_fail(struct fault_attr *attr, ssize_t size)
	{
	return should_fail_ex(attr, size, 0);
	}
	EXPORT_SYMBOL_GPL(should_fail);

	#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 void debugfs_create_ul(const char *name, umode_t mode,
	struct dentry parent, unsigned long value)
	{
	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 void debugfs_create_stacktrace_depth(const char *name, umode_t mode,
	struct dentry *parent,
	unsigned long *value)
	{
	debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth);
	}

	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

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

	dir = debugfs_create_dir(name, parent);
	if (IS_ERR(dir))
	return dir;

	debugfs_create_ul("probability", mode, dir, &attr->probability);
	debugfs_create_ul("interval", mode, dir, &attr->interval);
	debugfs_create_atomic_t("times", mode, dir, &attr->times);
	debugfs_create_atomic_t("space", mode, dir, &attr->space);
	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
	debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
	&attr->ratelimit_state.interval);
	debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
	&attr->ratelimit_state.burst);
	debugfs_create_bool("task-filter", mode, dir, &attr->task_filter);

	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
	&attr->stacktrace_depth);
	debugfs_create_xul("require-start", mode, dir, &attr->require_start);
	debugfs_create_xul("require-end", mode, dir, &attr->require_end);
	debugfs_create_xul("reject-start", mode, dir, &attr->reject_start);
	debugfs_create_xul("reject-end", mode, dir, &attr->reject_end);
	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

	attr->dname = dget(dir);
	return dir;
	}
	EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);

	#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

	#ifdef CONFIG_FAULT_INJECTION_CONFIGFS

	/* These configfs attribute utilities are copied from drivers/block/null_blk/main.c */

	static ssize_t fault_uint_attr_show(unsigned int val, char *page)
	{
	return snprintf(page, PAGE_SIZE, "%u\n", val);
	}

	static ssize_t fault_ulong_attr_show(unsigned long val, char *page)
	{
	return snprintf(page, PAGE_SIZE, "%lu\n", val);
	}

	static ssize_t fault_bool_attr_show(bool val, char *page)
	{
	return snprintf(page, PAGE_SIZE, "%u\n", val);
	}

	static ssize_t fault_atomic_t_attr_show(atomic_t val, char *page)
	{
	return snprintf(page, PAGE_SIZE, "%d\n", atomic_read(&val));
	}

	static ssize_t fault_uint_attr_store(unsigned int val, const char page, size_t count)
	{
	unsigned int tmp;
	int result;

	result = kstrtouint(page, 0, &tmp);
	if (result < 0)
	return result;

	*val = tmp;
	return count;
	}

	static ssize_t fault_ulong_attr_store(unsigned long val, const char page, size_t count)
	{
	int result;
	unsigned long tmp;

	result = kstrtoul(page, 0, &tmp);
	if (result < 0)
	return result;

	*val = tmp;
	return count;
	}

	static ssize_t fault_bool_attr_store(bool val, const char page, size_t count)
	{
	bool tmp;
	int result;

	result = kstrtobool(page, &tmp);
	if (result < 0)
	return result;

	*val = tmp;
	return count;
	}

	static ssize_t fault_atomic_t_attr_store(atomic_t val, const char page, size_t count)
	{
	int tmp;
	int result;

	result = kstrtoint(page, 0, &tmp);
	if (result < 0)
	return result;

	atomic_set(val, tmp);
	return count;
	}

	#define CONFIGFS_ATTR_NAMED(_pfx, _name, _attr_name) \
	static struct configfs_attribute _pfx##attr_##_name = { \
	.ca_name = _attr_name, \
	.ca_mode = 0644, \
	.ca_owner = THIS_MODULE, \
	.show = _pfx##_name##_show, \
	.store = _pfx##_name##_store, \
	}

	static struct fault_config to_fault_config(struct config_item item)
	{
	return container_of(to_config_group(item), struct fault_config, group);
	}

	#define FAULT_CONFIGFS_ATTR_NAMED(NAME, ATTR_NAME, MEMBER, TYPE) \
	static ssize_t fault_##NAME##_show(struct config_item item, char page) \
	{ \
	return fault_##TYPE##_attr_show(to_fault_config(item)->attr.MEMBER, page); \
	} \
	static ssize_t fault_##NAME##_store(struct config_item item, const char page, size_t count) \
	{ \
	struct fault_config *config = to_fault_config(item); \
	return fault_##TYPE##_attr_store(&config->attr.MEMBER, page, count); \
	} \
	CONFIGFS_ATTR_NAMED(fault_, NAME, ATTR_NAME)

	#define FAULT_CONFIGFS_ATTR(NAME, TYPE) \
	FAULT_CONFIGFS_ATTR_NAMED(NAME, __stringify(NAME), NAME, TYPE)

	FAULT_CONFIGFS_ATTR(probability, ulong);
	FAULT_CONFIGFS_ATTR(interval, ulong);
	FAULT_CONFIGFS_ATTR(times, atomic_t);
	FAULT_CONFIGFS_ATTR(space, atomic_t);
	FAULT_CONFIGFS_ATTR(verbose, ulong);
	FAULT_CONFIGFS_ATTR_NAMED(ratelimit_interval, "verbose_ratelimit_interval_ms",
	ratelimit_state.interval, uint);
	FAULT_CONFIGFS_ATTR_NAMED(ratelimit_burst, "verbose_ratelimit_burst",
	ratelimit_state.burst, uint);
	FAULT_CONFIGFS_ATTR_NAMED(task_filter, "task-filter", task_filter, bool);

	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER

	static ssize_t fault_stacktrace_depth_show(struct config_item item, char page)
	{
	return fault_ulong_attr_show(to_fault_config(item)->attr.stacktrace_depth, page);
	}

	static ssize_t fault_stacktrace_depth_store(struct config_item item, const char page,
	size_t count)
	{
	int result;
	unsigned long tmp;

	result = kstrtoul(page, 0, &tmp);
	if (result < 0)
	return result;

	to_fault_config(item)->attr.stacktrace_depth =
	min_t(unsigned long, tmp, MAX_STACK_TRACE_DEPTH);

	return count;
	}

	CONFIGFS_ATTR_NAMED(fault_, stacktrace_depth, "stacktrace-depth");

	static ssize_t fault_xul_attr_show(unsigned long val, char *page)
	{
	return snprintf(page, PAGE_SIZE,
	sizeof(val) == sizeof(u32) ? "0x%08lx\n" : "0x%016lx\n", val);
	}

	static ssize_t fault_xul_attr_store(unsigned long val, const char page, size_t count)
	{
	return fault_ulong_attr_store(val, page, count);
	}

	FAULT_CONFIGFS_ATTR_NAMED(require_start, "require-start", require_start, xul);
	FAULT_CONFIGFS_ATTR_NAMED(require_end, "require-end", require_end, xul);
	FAULT_CONFIGFS_ATTR_NAMED(reject_start, "reject-start", reject_start, xul);
	FAULT_CONFIGFS_ATTR_NAMED(reject_end, "reject-end", reject_end, xul);

	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */

	static struct configfs_attribute *fault_config_attrs[] = {
	&fault_attr_probability,
	&fault_attr_interval,
	&fault_attr_times,
	&fault_attr_space,
	&fault_attr_verbose,
	&fault_attr_ratelimit_interval,
	&fault_attr_ratelimit_burst,
	&fault_attr_task_filter,
	#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
	&fault_attr_stacktrace_depth,
	&fault_attr_require_start,
	&fault_attr_require_end,
	&fault_attr_reject_start,
	&fault_attr_reject_end,
	#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
	NULL,
	};

	static const struct config_item_type fault_config_type = {
	.ct_attrs = fault_config_attrs,
	.ct_owner = THIS_MODULE,
	};

	void fault_config_init(struct fault_config config, const char name)
	{
	config_group_init_type_name(&config->group, name, &fault_config_type);
	}
	EXPORT_SYMBOL_GPL(fault_config_init);

	#endif /* CONFIG_FAULT_INJECTION_CONFIGFS */