[patch 2/7] fault-injection capabilities infrastructure

Akinobu Mita
2006-10-12T07:43:31Z

[-- Attachment #1: should-fail.patch --]
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From: Akinobu Mita <akinobu.mita@gmail.com>

This patch provides base functions for implement fault-injection
capabilities.

- Lightweight random simulator is taken from crasher module for SUSE kernel

- The function should_fail() is taken from failmalloc-1.0
(http://www.nongnu.org/failmalloc/)

Cc: okuji@enbug.org
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Don Mullis <dwm@meer.net>

include/linux/fault-inject.h | 69 ++++++++++++++
lib/Kconfig.debug | 12 ++
lib/Makefile | 1
lib/fault-inject.c | 207 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 289 insertions(+)

Index: work-fault-inject/lib/Kconfig.debug
===================================================================
--- work-fault-inject.orig/lib/Kconfig.debug
+++ work-fault-inject/lib/Kconfig.debug
@@ -469,3 +469,15 @@ config LKDTM

Documentation on how to use the module can be found in
drivers/misc/lkdtm.c
+
+config FAULT_INJECTION
+ bool
+
+config FAULT_INJECTION_DEBUG_FS
+ bool "debugfs entries for fault-injection capabilities"
+ depends on FAULT_INJECTION && SYSFS
+ select DEBUG_FS
+ help
+ This option enables to configure fault-injection capabilities via
+ debugfs entries.
+
Index: work-fault-inject/lib/Makefile
===================================================================
--- work-fault-inject.orig/lib/Makefile
+++ work-fault-inject/lib/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o
obj-$(CONFIG_STATISTICS) += statistic.o

obj-$(CONFIG_SWIOTLB) += swiotlb.o
+obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o

lib-$(CONFIG_GENERIC_BUG) += bug.o

Index: work-fault-inject/include/linux/fault-inject.h
===================================================================
--- /dev/null
+++ work-fault-inject/include/linux/fault-inject.h
@@ -0,0 +1,69 @@
+#ifndef _LINUX_FAULT_INJECT_H
+#define _LINUX_FAULT_INJECT_H
+
+#ifdef CONFIG_FAULT_INJECTION
+
+#include <linux/types.h>
+#include <linux/debugfs.h>
+#include <asm/atomic.h>
+
+/*
+ * For explanation of the elements of this struct, see
+ * Documentation/fault-injection/fault-injection.txt
+ */
+struct fault_attr {
+ unsigned long probability;
+ unsigned long interval;
+ atomic_t times;
+ atomic_t space;
+ unsigned long verbose;
+
+ unsigned long count;
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+ struct {
+ struct dentry *dir;
+
+ struct dentry *probability_file;
+ struct dentry *interval_file;
+ struct dentry *times_file;
+ struct dentry *space_file;
+ struct dentry *verbose_file;
+ } entries;
+
+#endif
+};
+
+#define DEFINE_FAULT_ATTR(name) \
+ struct fault_attr name = { \
+ .interval = 1, \
+ .times = ATOMIC_INIT(1), \
+ }
+
+int setup_fault_attr(struct fault_attr *attr, char *str);
+void should_fail_srandom(unsigned long entropy);
+int should_fail(struct fault_attr *attr, ssize_t size);
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+int init_fault_attr_entries(struct fault_attr *attr, const char *name);
+void cleanup_fault_attr_entries(struct fault_attr *attr);
+
+#else /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+static inline int init_fault_attr_entries(struct fault_attr *attr,
+ const char *name)
+{
+ return -ENODEV;
+}
+
+static inline void cleanup_fault_attr_entries(struct fault_attr *attr)
+{
+}
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#endif /* CONFIG_FAULT_INJECTION */
+
+#endif /* _LINUX_FAULT_INJECT_H */
Index: work-fault-inject/lib/fault-inject.c
===================================================================
--- /dev/null
+++ work-fault-inject/lib/fault-inject.c
@@ -0,0 +1,207 @@
+#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/fault-inject.h>
+
+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;
+}
+
+#define failure_probability(attr) (attr)->probability
+#define failure_interval(attr) (attr)->interval
+#define max_failures(attr) (attr)->times
+#define current_space(attr) (attr)->space
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
+
+static unsigned long rand_seed = 152L;
+
+static unsigned long should_fail_random(void)
+{
+ rand_seed = rand_seed * 690690L+1;
+ return rand_seed ^ jiffies;
+}
+
+void should_fail_srandom(unsigned long entropy)
+{
+ rand_seed ^= entropy;
+ should_fail_random();
+}
+
+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();
+}
+
+/*
+ * This code is stolen from failmalloc-1.0
+ * http://www.nongnu.org/failmalloc/
+ */
+
+int should_fail(struct fault_attr *attr, ssize_t size)
+{
+ if (atomic_read(&max_failures(attr)) == 0)
+ return 0;
+
+ if (atomic_read(&current_space(attr)) > size) {
+ atomic_sub(size, &current_space(attr));
+ return 0;
+ }
+
+ if (failure_interval(attr) > 1) {
+ attr->count++;
+ if (attr->count % failure_interval(attr))
+ return 0;
+ }
+
+ if (failure_probability(attr) > should_fail_random() % 100)
+ goto fail;
+
+ return 0;
+
+fail:
+ fail_dump(attr);
+
+ if (atomic_read(&max_failures(attr)) != -1)
+ atomic_dec_not_zero(&max_failures(attr));
+
+ return 1;
+}
+
+#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_entries(struct fault_attr *attr)
+{
+ if (attr->entries.dir) {
+ if (attr->entries.probability_file) {
+ debugfs_remove(attr->entries.probability_file);
+ attr->entries.probability_file = NULL;
+ }
+ if (attr->entries.interval_file) {
+ debugfs_remove(attr->entries.interval_file);
+ attr->entries.interval_file = NULL;
+ }
+ if (attr->entries.times_file) {
+ debugfs_remove(attr->entries.times_file);
+ attr->entries.times_file = NULL;
+ }
+ if (attr->entries.space_file) {
+ debugfs_remove(attr->entries.space_file);
+ attr->entries.space_file = NULL;
+ }
+ if (attr->entries.verbose_file) {
+ debugfs_remove(attr->entries.verbose_file);
+ attr->entries.verbose_file = NULL;
+ }
+ debugfs_remove(attr->entries.dir);
+ attr->entries.dir = NULL;
+ }
+}
+
+int init_fault_attr_entries(struct fault_attr *attr, const char *name)
+{
+ mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+ struct dentry *dir;
+ struct dentry *file;
+
+ memset(&attr->entries, 0, sizeof(attr->entries));
+
+ dir = debugfs_create_dir(name, NULL);
+ if (!dir)
+ goto fail;
+ attr->entries.dir = dir;
+
+ file = debugfs_create_ul("probability", mode, dir, &attr->probability);
+ if (!file)
+ goto fail;
+ attr->entries.probability_file = file;
+
+ file = debugfs_create_ul("interval", mode, dir, &attr->interval);
+ if (!file)
+ goto fail;
+ attr->entries.interval_file = file;
+
+ file = debugfs_create_atomic_t("times", mode, dir, &attr->times);
+ if (!file)
+ goto fail;
+ attr->entries.times_file = file;
+
+ file = debugfs_create_atomic_t("space", mode, dir, &attr->space);
+ if (!file)
+ goto fail;
+ attr->entries.space_file = file;
+
+ file = debugfs_create_ul("verbose", mode, dir, &attr->verbose);
+ if (!file)
+ goto fail;
+ attr->entries.verbose_file = file;
+
+ return 0;
+fail:
+ cleanup_fault_attr_entries(attr);
+ return -ENOMEM;
+}
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

--