From 1357272fc7deeebb7b3c5d1a071562edc273cdaf Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Wed, 2 Oct 2013 20:41:01 +0300 Subject: Btrfs: fix a use-after-free bug in btrfs_dev_replace_finishing free_device rcu callback, scheduled from btrfs_rm_dev_replace_srcdev, can be processed before btrfs_scratch_superblock is called, which would result in a use-after-free on btrfs_device contents. Fix this by zeroing the superblock before the rcu callback is registered. Cc: Stefan Behrens Signed-off-by: Ilya Dryomov Signed-off-by: Josef Bacik --- fs/btrfs/dev-replace.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'fs/btrfs/dev-replace.c') diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 5d844438b2d4..2a9bd5bd24c3 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -535,10 +535,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list); btrfs_rm_dev_replace_srcdev(fs_info, src_device); - if (src_device->bdev) { - /* zero out the old super */ - btrfs_scratch_superblock(src_device); - } + /* * this is again a consistent state where no dev_replace procedure * is running, the target device is part of the filesystem, the -- cgit v1.2.3