Re: [PATCH] btrfs-progs: Check the csum tree node before go through the csum tree

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

Please ignore this patch since Wang's patch has already fixed them.

https://patchwork.kernel.org/patch/4254631/

Thanks,
Qu
-------- Original Message --------
Subject: [PATCH] btrfs-progs: Check the csum tree node before go through 
the csum tree
From: Qu Wenruo <quwenruo@cn.fujitsu.com>
To: <linux-btrfs@vger.kernel.org>
Date: 2014年09月30日 16:52
> [BUG]
> Some fsfuzzed btrfs image will cause btrfsck segfault.
>
> [REPRODUCER]
> Run btrfsck on a csum tree block corrupted image.
>
> [REASON]
> check_csums() function call btrfs_search_slot() on csum_tree but doesn't
> check whether the csum_tree contains a valid extent_buffer, which causes
> the segfault.
>
> [FIX]
> Check the csum_root->node before any search.
>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>   cmds-check.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/cmds-check.c b/cmds-check.c
> index 9471709..537376a 100644
> --- a/cmds-check.c
> +++ b/cmds-check.c
> @@ -3905,6 +3905,10 @@ static int check_csums(struct btrfs_root *root)
>   	unsigned long leaf_offset;
>   
>   	root = root->fs_info->csum_root;
> +	if (!extent_buffer_uptodate(root->node)) {
> +		fprintf(stderr, "No valid csum tree found\n");
> +		return -ENOENT;
> +	}
>   
>   	key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
>   	key.type = BTRFS_EXTENT_CSUM_KEY;