The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

1742e1c90c3d ("btrfs: fix extent map use-after-free when handling missing device in read_one_chunk") ff37c89f94be ("btrfs: move missing device handling in a dedicate function") 562d7b1512f7 ("btrfs: handle device lookup with btrfs_dev_lookup_args")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1742e1c90c3da344f3bb9b1f1309b3f47482756a Mon Sep 17 00:00:00 2001 From: void0red void0red@gmail.com Date: Wed, 23 Nov 2022 22:39:45 +0800 Subject: [PATCH] btrfs: fix extent map use-after-free when handling missing device in read_one_chunk

Store the error code before freeing the extent_map. Though it's reference counted structure, in that function it's the first and last allocation so this would lead to a potential use-after-free.

The error can happen eg. when chunk is stored on a missing device and the degraded mount option is missing.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216721 Reported-by: eriri 1527030098@qq.com Fixes: adfb69af7d8c ("btrfs: add_missing_dev() should return the actual error") CC: stable@vger.kernel.org # 4.9+ Signed-off-by: void0red void0red@gmail.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index acab20f2863d..aa25fa335d3e 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6976,8 +6976,9 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf, map->stripes[i].dev = handle_missing_device(fs_info, devid, uuid); if (IS_ERR(map->stripes[i].dev)) { + ret = PTR_ERR(map->stripes[i].dev); free_extent_map(em); - return PTR_ERR(map->stripes[i].dev); + return ret; } }