[PATCH 3.16 022/294] libceph: potential NULL dereference in ceph_msg_data_create()

[Ben Hutchings]

3.16.50-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpen...@oracle.com>

commit 7c40b22f6f84c98a1d36e6d0a4346e58f05e45d8 upstream.

If kmem_cache_zalloc() returns NULL then the INIT_LIST_HEAD(&data->links);
will Oops.  The callers aren't really prepared for NULL returns so it
doesn't make a lot of difference in real life.

Fixes: 5240d9f95dfe ("libceph: replace message data pointer with list")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Ilya Dryomov <idryo...@gmail.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 net/ceph/messenger.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3075,8 +3075,10 @@ static struct ceph_msg_data *ceph_msg_da
                return NULL;
 
        data = kmem_cache_zalloc(ceph_msg_data_cache, GFP_NOFS);
-       if (data)
-               data->type = type;
+       if (!data)
+               return NULL;
+
+       data->type = type;
        INIT_LIST_HEAD(&data->links);
 
        return data;