aio: table lookup: verify ctx pointer
authorBenjamin LaHaise <bcrl@kvack.org>
Wed, 7 Aug 2013 22:23:48 +0000 (18:23 -0400)
committerBenjamin LaHaise <bcrl@kvack.org>
Wed, 7 Aug 2013 22:23:48 +0000 (18:23 -0400)
Another shortcoming of the table lookup patch was revealed where the pointer
was not being tested before being dereferenced.  Verify this to avoid the
NULL pointer dereference.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
fs/aio.c

index 3bc068c1cb9cbfaec0e33dfe5efd26ec361e2c93..c3f005dc2d55211ea055ad8ccc9715a76eff24ac 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -812,7 +812,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
                goto out;
 
        ctx = table->table[id];
-       if (ctx->user_id == ctx_id) {
+       if (ctx && ctx->user_id == ctx_id) {
                percpu_ref_get(&ctx->users);
                ret = ctx;
        }