[Cluster-devel] [GFS2 PATCH] GFS2: attempt to access beyond end of device creating file

[Steven Whitehouse]

Hi,

On Tue, 2012-03-13 at 13:55 -0400, Bob Peterson wrote:
> Hi,
> 
> This patch initializes the hash table cache when inodes are
> created in order to prevent using a hash table pointer left over
> from a previous inode. It also adds boundary checking on the
> hash table.
> 
> Regards,
> 
> Bob Peterson
> Red Hat File Systems
> 
> Signed-off-by: Bob Peterson <rpeterso at redhat.com> 
> --
> diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
> index c35573a..c2eb20f 100644
> --- a/fs/gfs2/dir.c
> +++ b/fs/gfs2/dir.c
> @@ -740,6 +740,7 @@ static int get_leaf_nr(struct gfs2_inode *dip, u32 index,
>  	hash = gfs2_dir_get_hash_table(dip);
>  	if (IS_ERR(hash))
>  		return PTR_ERR(hash);
> +	BUG_ON(index >= (1 << dip->i_depth));
>  	*leaf_out = be64_to_cpu(*(hash + index));
>  	return 0;
>  }
> diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
> index 6172fa7..bd2abe3 100644
> --- a/fs/gfs2/super.c
> +++ b/fs/gfs2/super.c
> @@ -1576,6 +1576,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
>  		ip->i_flags = 0;
>  		ip->i_gl = NULL;
>  		ip->i_rgd = NULL;
> +		ip->i_hash_cache = NULL;
>  	}
>  	return &ip->i_inode;
>  }
> 

The question is how does this pointer land up being not NULL to start
with... I thought that you were looking into that from your earlier
comment in the bug,

Steve.