Re: [PATCH 5.10 004/161] btrfs: send: check for inline extents in range_is_hole_in_parent()

Ben Hutchings
2026-02-04T19:10:34Z

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On Wed, 2026-02-04 at 15:37 +0100, Greg Kroah-Hartman wrote:
> 5.10-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Qu Wenruo <wqu@suse.com>
>
> [ Upstream commit 08b096c1372cd69627f4f559fb47c9fb67a52b39 ]
>
> Before accessing the disk_bytenr field of a file extent item we need
> to check if we are dealing with an inline extent.
> This is because for inline extents their data starts at the offset of
> the disk_bytenr field. So accessing the disk_bytenr
> means we are accessing inline data or in case the inline data is less
> than 8 bytes we can actually cause an invalid
> memory access if this inline extent item is the first item in the leaf
> or access metadata from other items.
>
> Fixes: 82bfb2e7b645 ("Btrfs: incremental send, fix unnecessary hole writes for sparse files")
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> Reviewed-by: David Sterba <dsterba@suse.com>
> Signed-off-by: David Sterba <dsterba@suse.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> fs/btrfs/send.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index d86b4d13cae48..f144171ed6b7e 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -5892,6 +5892,8 @@ static int range_is_hole_in_parent(struct send_ctx *sctx,
> extent_end = btrfs_file_extent_end(path);
> if (extent_end <= start)
> goto next;
> + if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE)
> + return 0;

This will leak path, unless (at least) commits 4c74a32ad323 "btrfs:
DEFINE_FREE for struct btrfs_path" and 4ca6f24a52c4 "btrfs: more trivial
BTRFS_PATH_AUTO_FREE conversions" are also backported.

That could be avoided by using { ret = 0; goto out; } here instead of
simply returning.

Ben.

> if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) {
> search_start = extent_end;
> goto next;

--
Ben Hutchings
A free society is one where it is safe to be unpopular.
- Adlai Stevenson

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