Commit 8a8b6502 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
Browse files

[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: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6ff1cb35
...@@ -86,7 +86,6 @@ configuration of fault-injection capabilities. ...@@ -86,7 +86,6 @@ configuration of fault-injection capabilities.
specifies the maximum stacktrace depth walked during search specifies the maximum stacktrace depth walked during search
for a caller within [address-start,address-end). for a caller within [address-start,address-end).
- /debug/failslab/ignore-gfp-highmem:
- /debug/fail_page_alloc/ignore-gfp-highmem: - /debug/fail_page_alloc/ignore-gfp-highmem:
Format: { 0 | 1 } Format: { 0 | 1 }
...@@ -167,7 +166,6 @@ echo 10 > /debug/$FAILNAME/probability ...@@ -167,7 +166,6 @@ echo 10 > /debug/$FAILNAME/probability
echo 100 > /debug/$FAILNAME/interval echo 100 > /debug/$FAILNAME/interval
echo -1 > /debug/$FAILNAME/times echo -1 > /debug/$FAILNAME/times
echo 2 > /debug/$FAILNAME/verbose echo 2 > /debug/$FAILNAME/verbose
echo 1 > /debug/$FAILNAME/ignore-gfp-highmem
echo 1 > /debug/$FAILNAME/ignore-gfp-wait echo 1 > /debug/$FAILNAME/ignore-gfp-wait
blacklist() blacklist()
......
...@@ -417,6 +417,13 @@ config LKDTM ...@@ -417,6 +417,13 @@ config LKDTM
config FAULT_INJECTION config FAULT_INJECTION
bool 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 config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities" bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS depends on FAULT_INJECTION && SYSFS
......
...@@ -107,6 +107,7 @@ ...@@ -107,6 +107,7 @@
#include <linux/nodemask.h> #include <linux/nodemask.h>
#include <linux/mempolicy.h> #include <linux/mempolicy.h>
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/fault-inject.h>
#include <linux/rtmutex.h> #include <linux/rtmutex.h>
#include <asm/cacheflush.h> #include <asm/cacheflush.h>
...@@ -3088,12 +3089,88 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, ...@@ -3088,12 +3089,88 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
#endif #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) static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
{ {
void *objp; void *objp;
struct array_cache *ac; struct array_cache *ac;
check_irq_off(); check_irq_off();
if (should_failslab(cachep, flags))
return NULL;
ac = cpu_cache_get(cachep); ac = cpu_cache_get(cachep);
if (likely(ac->avail)) { if (likely(ac->avail)) {
STATS_INC_ALLOCHIT(cachep); STATS_INC_ALLOCHIT(cachep);
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment