diff options
| author | Ilya Dryomov <idryomov@gmail.com> | 2013-10-02 19:41:01 +0200 |
|---|---|---|
| committer | Josef Bacik <jbacik@fusionio.com> | 2013-10-04 22:02:14 +0200 |
| commit | 1357272fc7deeebb7b3c5d1a071562edc273cdaf (patch) | |
| tree | 37af6be54b03e07b4fb06a2ddc4c5ac739c53032 | |
| parent | Btrfs: eliminate races in worker stopping code (diff) | |
| download | linux-1357272fc7deeebb7b3c5d1a071562edc273cdaf.tar.xz linux-1357272fc7deeebb7b3c5d1a071562edc273cdaf.zip | |
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 <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
| -rw-r--r-- | fs/btrfs/dev-replace.c | 5 | ||||
| -rw-r--r-- | fs/btrfs/volumes.c | 7 |
2 files changed, 7 insertions, 5 deletions
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 diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 043114749516..b0203b1322ac 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1716,6 +1716,7 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info, struct btrfs_device *srcdev) { WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex)); + list_del_rcu(&srcdev->dev_list); list_del_rcu(&srcdev->dev_alloc_list); fs_info->fs_devices->num_devices--; @@ -1725,9 +1726,13 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info, } if (srcdev->can_discard) fs_info->fs_devices->num_can_discard--; - if (srcdev->bdev) + if (srcdev->bdev) { fs_info->fs_devices->open_devices--; + /* zero out the old super */ + btrfs_scratch_superblock(srcdev); + } + call_rcu(&srcdev->rcu, free_device); } |