Re: [syzbot] [btrfs?] general protection fault in btrfs_search_slot

[Qu Wenruo]

在 2024/10/25 12:53, Lizhi Xu 写道:
> use the input logical can't find the extent root, so add sanity check for
> extent root before search slot.
>
> #syz test
>
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index f8e1d5b2c512..87eaf5dd2d5d 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -2213,6 +2213,9 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
>   	key.objectid = logical;
>   	key.offset = (u64)-1;
>
> +	if (!extent_root)
> +		return -ENOENT;

Considering we have a lot of such btrfs_search_slot() without checking
if the csum/extent root is NULL, can we move the check into
btrfs_search_slot()?

Thanks,
Qu
> +
>   	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
>   	if (ret < 0)
>   		return ret;