[3.11.y.z extended stable] Patch "fs: btrfs: volumes.c: Fix for possible null pointer dereference" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    fs: btrfs: volumes.c: Fix for possible null pointer dereference

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 1b7d9ec4827c1f37546d30b7a3be59cf5b8cc85a Mon Sep 17 00:00:00 2001
From: Rickard Strandqvist <rickard_strandqvist at spectrumdigital.se>
Date: Thu, 22 May 2014 22:43:43 +0200
Subject: fs: btrfs: volumes.c: Fix for possible null pointer dereference

commit 8321cf2596d283821acc466377c2b85bcd3422b7 upstream.

There is otherwise a risk of a possible null pointer dereference.

Was largely found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist at spectrumdigital.se>
Signed-off-by: Chris Mason <clm at fb.com>
Cc: David Sterba <dsterba at suse.cz>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/btrfs/volumes.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ca9a51400035..03f47b09f37f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1635,11 +1635,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 		struct btrfs_fs_devices *fs_devices;
 		fs_devices = root->fs_info->fs_devices;
 		while (fs_devices) {
-			if (fs_devices->seed == cur_devices)
+			if (fs_devices->seed == cur_devices) {
+				fs_devices->seed = cur_devices->seed;
 				break;
+			}
 			fs_devices = fs_devices->seed;
 		}
-		fs_devices->seed = cur_devices->seed;
 		cur_devices->seed = NULL;
 		lock_chunks(root);
 		__btrfs_close_devices(cur_devices);
--
1.9.1