diff options
author | Howard McLauchlan <hmclauchlan@fb.com> | 2018-04-05 16:23:57 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-05 21:36:26 -0700 |
commit | 4f6923fbb352d126659cabe34806cff75c7b5ea0 (patch) | |
tree | f88b75ada9b91b9f78344f7c719ba38b0e1c439d | |
parent | 14298d3663e44705d3f9106343ac8298a5fdff99 (diff) | |
download | linux-4f6923fbb352d126659cabe34806cff75c7b5ea0.tar.gz |
mm: make should_failslab always available for fault injection
should_failslab() is a convenient function to hook into for directed error injection into kmalloc(). However, it is only available if a config flag is set. The following BCC script, for example, fails kmalloc() calls after a btrfs umount: from bcc import BPF prog = r""" BPF_HASH(flag); #include <linux/mm.h> int kprobe__btrfs_close_devices(void *ctx) { u64 key = 1; flag.update(&key, &key); return 0; } int kprobe__should_failslab(struct pt_regs *ctx) { u64 key = 1; u64 *res; res = flag.lookup(&key); if (res != 0) { bpf_override_return(ctx, -ENOMEM); } return 0; } """ b = BPF(text=prog) while 1: b.kprobe_poll() This patch refactors the should_failslab implementation so that the function is always available for error injection, independent of flags. This change would be similar in nature to commit f5490d3ec921 ("block: Add should_fail_bio() for bpf error injection"). Link: http://lkml.kernel.org/r/20180222020320.6944-1-hmclauchlan@fb.com Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/linux/fault-inject.h | 5 | ||||
-rw-r--r-- | mm/failslab.c | 2 | ||||
-rw-r--r-- | mm/slab_common.c | 8 |
3 files changed, 12 insertions, 3 deletions
diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index c3c95d18bf43..7e6c77740413 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -64,10 +64,11 @@ static inline struct dentry *fault_create_debugfs_attr(const char *name, struct kmem_cache; +int should_failslab(struct kmem_cache *s, gfp_t gfpflags); #ifdef CONFIG_FAILSLAB -extern bool should_failslab(struct kmem_cache *s, gfp_t gfpflags); +extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags); #else -static inline bool should_failslab(struct kmem_cache *s, gfp_t gfpflags) +static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) { return false; } diff --git a/mm/failslab.c b/mm/failslab.c index 8087d976a809..1f2f248e3601 100644 --- a/mm/failslab.c +++ b/mm/failslab.c @@ -14,7 +14,7 @@ static struct { .cache_filter = false, }; -bool should_failslab(struct kmem_cache *s, gfp_t gfpflags) +bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags) { /* No fault-injection for bootstrap cache */ if (unlikely(s == kmem_cache)) diff --git a/mm/slab_common.c b/mm/slab_common.c index 2e682a4c8877..98dcdc352062 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1516,3 +1516,11 @@ EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); EXPORT_TRACEPOINT_SYMBOL(kfree); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); + +int should_failslab(struct kmem_cache *s, gfp_t gfpflags) +{ + if (__should_failslab(s, gfpflags)) + return -ENOMEM; + return 0; +} +ALLOW_ERROR_INJECTION(should_failslab, ERRNO); |