failslab: add ability to filter slab caches
This patch allow to inject faults only for specific slabs.
In order to preserve default behavior cache filter is off by
default (all caches are faulty).
One may define specific set of slabs like this:
# mark skbuff_head_cache as faulty
echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab
# Turn on cache filter (off by default)
echo 1 > /sys/kernel/debug/failslab/cache-filter
# Turn on fault injection
echo 1 > /sys/kernel/debug/failslab/times
echo 1 > /sys/kernel/debug/failslab/probability
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
diff --git a/mm/failslab.c b/mm/failslab.c
index 9339de5..bb41f98 100644
--- a/mm/failslab.c
+++ b/mm/failslab.c
@@ -1,18 +1,22 @@
#include <linux/fault-inject.h>
#include <linux/gfp.h>
+#include <linux/slab.h>
static struct {
struct fault_attr attr;
u32 ignore_gfp_wait;
+ int cache_filter;
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
struct dentry *ignore_gfp_wait_file;
+ struct dentry *cache_filter_file;
#endif
} failslab = {
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_wait = 1,
+ .cache_filter = 0,
};
-bool should_failslab(size_t size, gfp_t gfpflags)
+bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags)
{
if (gfpflags & __GFP_NOFAIL)
return false;
@@ -20,6 +24,9 @@
if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT))
return false;
+ if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB))
+ return false;
+
return should_fail(&failslab.attr, size);
}
@@ -30,7 +37,6 @@
__setup("failslab=", setup_failslab);
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-
static int __init failslab_debugfs_init(void)
{
mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
@@ -46,8 +52,14 @@
debugfs_create_bool("ignore-gfp-wait", mode, dir,
&failslab.ignore_gfp_wait);
- if (!failslab.ignore_gfp_wait_file) {
+ failslab.cache_filter_file =
+ debugfs_create_bool("cache-filter", mode, dir,
+ &failslab.cache_filter);
+
+ if (!failslab.ignore_gfp_wait_file ||
+ !failslab.cache_filter_file) {
err = -ENOMEM;
+ debugfs_remove(failslab.cache_filter_file);
debugfs_remove(failslab.ignore_gfp_wait_file);
cleanup_fault_attr_dentries(&failslab.attr);
}