diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2021-01-25 16:42:35 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-09 11:11:10 +0100 |
| commit | a01415e5e862a60a52b10081532e09f9b3503592 (patch) | |
| tree | ad024ea209ad5d5d492c27152511da83055476eb /fs/btrfs/free-space-cache.c | |
| parent | fbefc2d2890021b1c57cb816983e529fb64eebd1 (diff) | |
btrfs: avoid double put of block group when emptying cluster
commit 95c85fba1f64c3249c67f0078a29f8a125078189 upstream.
It's wrong calling btrfs_put_block_group in
__btrfs_return_cluster_to_free_space if the block group passed is
different than the block group the cluster represents. As this means the
cluster doesn't have a reference to the passed block group. This results
in double put and a use-after-free bug.
Fix this by simply bailing if the block group we passed in does not
match the block group on the cluster.
Fixes: fa9c0d795f7b ("Btrfs: rework allocation clustering")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
| -rw-r--r-- | fs/btrfs/free-space-cache.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index ae4059ce2f84..9ebc8e2237e8 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -2714,8 +2714,10 @@ static void __btrfs_return_cluster_to_free_space( struct rb_node *node; spin_lock(&cluster->lock); - if (cluster->block_group != block_group) - goto out; + if (cluster->block_group != block_group) { + spin_unlock(&cluster->lock); + return; + } cluster->block_group = NULL; cluster->window_start = 0; @@ -2753,8 +2755,6 @@ static void __btrfs_return_cluster_to_free_space( entry->offset, &entry->offset_index, bitmap); } cluster->root = RB_ROOT; - -out: spin_unlock(&cluster->lock); btrfs_put_block_group(block_group); } |