Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH] btrfs: use after free when closing devices | Date | Tue, 12 May 2015 19:31:37 -0400 |
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__btrfs_close_devices() would call_rcu to free the device, which is racy with list_for_each_entry() accessing the memory to retrieve the next device on the list.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com> --- fs/btrfs/volumes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 8e8d1d1..253b349 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -693,13 +693,13 @@ static void free_device(struct rcu_head *head) static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) { - struct btrfs_device *device; + struct btrfs_device *device, *tmp; if (--fs_devices->opened > 0) return 0; mutex_lock(&fs_devices->device_list_mutex); - list_for_each_entry(device, &fs_devices->devices, dev_list) { + list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) { struct btrfs_device *new_device; struct rcu_string *name; -- 1.7.10.4
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