The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 669e859b5ea7c6f4fce0149d3907c64e550c294b Mon Sep 17 00:00:00 2001

From: Dan Carpenter dan.carpenter@oracle.com Date: Mon, 11 Feb 2019 21:32:10 +0300 Subject: [PATCH] btrfs: drop the lock on error in btrfs_dev_replace_cancel

We should drop the lock on this error path. This has been found by a static tool.

The lock needs to be released, it's there to protect access to the dev_replace members and is not supposed to be left locked. The value of state that's being switched would need to be artifically changed to an invalid value so the default: branch is taken.

Fixes: d189dd70e255 ("btrfs: fix use-after-free due to race between replace start and cancel") CC: stable@vger.kernel.org # 5.0+ Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 13863354ff9d..ee193c5222b2 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -862,6 +862,7 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info) btrfs_destroy_dev_replace_tgtdev(tgt_device); break; default: + up_write(&dev_replace->rwsem); result = -EINVAL; }