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authorAkinobu Mita <akinobu.mita@gmail.com>2006-12-08 02:39:44 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-08 08:29:02 -0800
commit8a8b6502fb669c3a0638a08955442814cedc86b1 (patch)
tree2e49652f904eb821f2fa7ae8cab0dd9b756772d9
parent6ff1cb355e628f8fc55fa2d01e269e5e1bbc2fe9 (diff)
[PATCH] fault-injection capability for kmalloc
This patch provides fault-injection capability for kmalloc. Boot option: failslab=<interval>,<probability>,<space>,<times> <interval> -- specifies the interval of failures. <probability> -- specifies how often it should fail in percent. <space> -- specifies the size of free space where memory can be allocated safely in bytes. <times> -- specifies how many times failures may happen at most. Debugfs: /debug/failslab/interval /debug/failslab/probability /debug/failslab/specifies /debug/failslab/times /debug/failslab/ignore-gfp-highmem /debug/failslab/ignore-gfp-wait Example: failslab=10,100,0,-1 slab allocation (kmalloc(), kmem_cache_alloc(),..) fails once per 10 times. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--Documentation/fault-injection/fault-injection.txt2
-rw-r--r--lib/Kconfig.debug7
-rw-r--r--mm/slab.c77
3 files changed, 84 insertions, 2 deletions
diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 260ce6c199ce..cf075c20eda0 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -86,7 +86,6 @@ configuration of fault-injection capabilities.
specifies the maximum stacktrace depth walked during search
for a caller within [address-start,address-end).
-- /debug/failslab/ignore-gfp-highmem:
- /debug/fail_page_alloc/ignore-gfp-highmem:
Format: { 0 | 1 }
@@ -167,7 +166,6 @@ echo 10 > /debug/$FAILNAME/probability
echo 100 > /debug/$FAILNAME/interval
echo -1 > /debug/$FAILNAME/times
echo 2 > /debug/$FAILNAME/verbose
-echo 1 > /debug/$FAILNAME/ignore-gfp-highmem
echo 1 > /debug/$FAILNAME/ignore-gfp-wait
blacklist()
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 35228b3e7e92..c7f567a57d7d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -417,6 +417,13 @@ config LKDTM
config FAULT_INJECTION
bool
+config FAILSLAB
+ bool "Fault-injection capabilitiy for kmalloc"
+ depends on DEBUG_KERNEL
+ select FAULT_INJECTION
+ help
+ This option provides fault-injection capabilitiy for kmalloc.
+
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS
diff --git a/mm/slab.c b/mm/slab.c
index e90b6100a927..47011e2ef3c9 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -107,6 +107,7 @@
#include <linux/nodemask.h>
#include <linux/mempolicy.h>
#include <linux/mutex.h>
+#include <linux/fault-inject.h>
#include <linux/rtmutex.h>
#include <asm/cacheflush.h>
@@ -3088,12 +3089,88 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
#define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
#endif
+#ifdef CONFIG_FAILSLAB
+
+static struct failslab_attr {
+
+ struct fault_attr attr;
+
+ u32 ignore_gfp_wait;
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+ struct dentry *ignore_gfp_wait_file;
+#endif
+
+} failslab = {
+ .attr = FAULT_ATTR_INITIALIZER,
+};
+
+static int __init setup_failslab(char *str)
+{
+ return setup_fault_attr(&failslab.attr, str);
+}
+__setup("failslab=", setup_failslab);
+
+static int should_failslab(struct kmem_cache *cachep, gfp_t flags)
+{
+ if (cachep == &cache_cache)
+ return 0;
+ if (flags & __GFP_NOFAIL)
+ return 0;
+ if (failslab.ignore_gfp_wait && (flags & __GFP_WAIT))
+ return 0;
+
+ return should_fail(&failslab.attr, obj_size(cachep));
+}
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+static int __init failslab_debugfs(void)
+{
+ mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+ struct dentry *dir;
+ int err;
+
+ err = init_fault_attr_dentries(&failslab.attr, "failslab");
+ if (err)
+ return err;
+ dir = failslab.attr.dentries.dir;
+
+ failslab.ignore_gfp_wait_file =
+ debugfs_create_bool("ignore-gfp-wait", mode, dir,
+ &failslab.ignore_gfp_wait);
+
+ if (!failslab.ignore_gfp_wait_file) {
+ err = -ENOMEM;
+ debugfs_remove(failslab.ignore_gfp_wait_file);
+ cleanup_fault_attr_dentries(&failslab.attr);
+ }
+
+ return err;
+}
+
+late_initcall(failslab_debugfs);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#else /* CONFIG_FAILSLAB */
+
+static inline int should_failslab(struct kmem_cache *cachep, gfp_t flags)
+{
+ return 0;
+}
+
+#endif /* CONFIG_FAILSLAB */
+
static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
{
void *objp;
struct array_cache *ac;
check_irq_off();
+
+ if (should_failslab(cachep, flags))
+ return NULL;
+
ac = cpu_cache_get(cachep);
if (likely(ac->avail)) {
STATS_INC_ALLOCHIT(cachep);