From 67a2c45ee7f4f250458279a2e1244679c5d9735c Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Wed, 3 Sep 2014 21:35:43 +0800 Subject: Btrfs: fix use-after-free problem of the device during device replace The problem is: Task0(device scan task) Task1(device replace task) scan_one_device() mutex_lock(&uuid_mutex) device = find_device() mutex_lock(&device_list_mutex) lock_chunk() rm_and_free_source_device unlock_chunk() mutex_unlock(&device_list_mutex) check device Destroying the target device if device replace fails also has the same problem. We fix this problem by locking uuid_mutex during destroying source device or target device, just like the device remove operation. It is a temporary solution, we can fix this problem and make the code more clear by atomic counter in the future. Signed-off-by: Miao Xie Signed-off-by: Chris Mason --- fs/btrfs/volumes.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/btrfs/volumes.h') diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 76600a3fedbe..2b37da3dd408 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -24,6 +24,8 @@ #include #include "async-thread.h" +extern struct mutex uuid_mutex; + #define BTRFS_STRIPE_LEN (64 * 1024) struct buffer_head; -- cgit v1.2.3