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authorHoward McLauchlan <hmclauchlan@fb.com>2018-04-05 16:23:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-05 21:36:26 -0700
commit4f6923fbb352d126659cabe34806cff75c7b5ea0 (patch)
treef88b75ada9b91b9f78344f7c719ba38b0e1c439d /mm
parent14298d3663e44705d3f9106343ac8298a5fdff99 (diff)
downloadlinux-4f6923fbb352d126659cabe34806cff75c7b5ea0.tar.bz2
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>
Diffstat (limited to 'mm')
-rw-r--r--mm/failslab.c2
-rw-r--r--mm/slab_common.c8
2 files changed, 9 insertions, 1 deletions
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);