block: null_blk: fix use after free
entry(cmd->ll_list) may belong to new request once end_cmd()
returns, so fix the bug with the patch.
Without the change, it is easy to observe oops when
doing null_blk(timer) test.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 8e7e3a0..e932398 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -203,8 +203,8 @@
entry = llist_reverse_order(entry);
do {
cmd = container_of(entry, struct nullb_cmd, ll_list);
- end_cmd(cmd);
entry = entry->next;
+ end_cmd(cmd);
} while (entry);
}