bcache: fix cache_set_flush() NULL pointer dereference on OOM
When bch_cache_set_alloc() fails to kzalloc the cache_set, the
asyncronous closure handling tries to dereference a cache_set that
hadn't yet been allocated inside of cache_set_flush() which is called
by __cache_set_unregister() during cleanup. This appears to happen only
during an OOM condition on bcache_register.
Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 6b07a0c..a296425 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1373,6 +1373,9 @@
struct btree *b;
unsigned i;
+ if (!c)
+ closure_return(cl);
+
bch_cache_accounting_destroy(&c->accounting);
kobject_put(&c->internal);