From 2839600893b79eb3efcf4929c6ee062ed6f08d6e Mon Sep 17 00:00:00 2001 From: Hongling Zeng Date: Mon, 31 Aug 2026 13:38:01 +0800 Subject: [PATCH] btrfs: take commit root semaphore when iterating in mark_block_group_to_copy() mark_block_group_to_copy() iterates over the commit root with skip_locking=true. A concurrent transaction commit can swap and free the commit root during iteration, causing use-after-free when accessing extent buffers. Fix it by using path->need_commit_sem to protect the commit root search. Fixes: 78ce9fc269af ("btrfs: zoned: mark block groups to copy for device-replace") CC: stable@vger.kernel.org Assisted-by: Codex:gpt-5.5 Reviewed-by: Johannes Thumshirn Signed-off-by: Hongling Zeng Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/dev-replace.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 22eea188a3280..cdfe093e5c5c4 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -498,6 +498,7 @@ static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info, path->reada = READA_FORWARD; path->search_commit_root = true; path->skip_locking = true; + path->need_commit_sem = true; key.objectid = src_dev->devid; key.type = BTRFS_DEV_EXTENT_KEY; -- 2.53.0