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-rw-r--r--include/linux/fault-inject.h69
-rw-r--r--lib/Kconfig.debug12
-rw-r--r--lib/Makefile1
-rw-r--r--lib/fault-inject.c183
4 files changed, 265 insertions, 0 deletions
diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
new file mode 100644
index 0000000..4df4902
--- /dev/null
+++ b/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;
+ } dentries;
+
+#endif
+};
+
+#define FAULT_ATTR_INITIALIZER { \
+ .interval = 1, \
+ .times = ATOMIC_INIT(1), \
+ }
+
+#define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER
+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_dentries(struct fault_attr *attr, const char *name);
+void cleanup_fault_attr_dentries(struct fault_attr *attr);
+
+#else /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+static inline int init_fault_attr_dentries(struct fault_attr *attr,
+ const char *name)
+{
+ return -ENODEV;
+}
+
+static inline void cleanup_fault_attr_dentries(struct fault_attr *attr)
+{
+}
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#endif /* CONFIG_FAULT_INJECTION */
+
+#endif /* _LINUX_FAULT_INJECT_H */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2c133c0..35228b3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -413,3 +413,15 @@ 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 enable configuration of fault-injection capabilities via
+ debugfs.
+
diff --git a/lib/Makefile b/lib/Makefile
index 6f675c6..2d6106a 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_SMP) += percpu_counter.o
obj-$(CONFIG_AUDIT_GENERIC) += audit.o
obj-$(CONFIG_SWIOTLB) += swiotlb.o
+obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
lib-$(CONFIG_GENERIC_BUG) += bug.o
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
new file mode 100644
index 0000000..a7cb3af
--- /dev/null
+++ b/lib/fault-inject.c
@@ -0,0 +1,183 @@
+#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>
+
+/*
+ * 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)
+
+/*
+ * 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(&attr->times) == 0)
+ return 0;
+
+ if (atomic_read(&attr->space) > size) {
+ atomic_sub(size, &attr->space);
+ return 0;
+ }
+
+ if (attr->interval > 1) {
+ attr->count++;
+ if (attr->count % attr->interval)
+ return 0;
+ }
+
+ if (attr->probability > random32() % 100)
+ goto fail;
+
+ return 0;
+
+fail:
+ fail_dump(attr);
+
+ if (atomic_read(&attr->times) != -1)
+ atomic_dec_not_zero(&attr->times);
+
+ 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_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;
+
+ 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);
+
+ if (!attr->dentries.probability_file || !attr->dentries.interval_file
+ || !attr->dentries.times_file || !attr->dentries.space_file
+ || !attr->dentries.verbose_file)
+ goto fail;
+
+ return 0;
+fail:
+ cleanup_fault_attr_dentries(attr);
+ return -ENOMEM;
+}
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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