This is a note to let you know that I've just added the patch titled
btrfs: avoid double put of block group when emptying cluster
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-avoid-double-put-of-block-group-when-emptying-cluster.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 95c85fba1f64c3249c67f0078a29f8a125078189 Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@xxxxxxxxxxxxxx>
Date: Mon, 25 Jan 2021 16:42:35 -0500
Subject: btrfs: avoid double put of block group when emptying cluster
From: Josef Bacik <josef@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx # 4.4+
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/free-space-cache.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2714,8 +2714,10 @@ static void __btrfs_return_cluster_to_fr
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_fr
entry->offset, &entry->offset_index, bitmap);
}
cluster->root = RB_ROOT;
-
-out:
spin_unlock(&cluster->lock);
btrfs_put_block_group(block_group);
}
Patches currently in stable-queue which might be from josef@xxxxxxxxxxxxxx are
queue-5.10/btrfs-fix-race-between-extent-freeing-allocation-when-using-bitmaps.patch
queue-5.10/btrfs-fix-stale-data-exposure-after-cloning-a-hole-with-no_holes-enabled.patch
queue-5.10/btrfs-avoid-double-put-of-block-group-when-emptying-cluster.patch
queue-5.10/btrfs-fix-race-between-writes-to-swap-files-and-scrub.patch
queue-5.10/btrfs-fix-race-between-swap-file-activation-and-snapshot-creation.patch
