Re: [PATCH 08/11] xfsprogs: xfs_repair: fix possible null dereference in build_ino_tree

[Dave Chinner <david@xxxxxxxxxxxxx>]

On Wed, Dec 02, 2015 at 04:49:24PM +0530, Vivek Trivedi wrote:
> Fix possible null dereference in build_ino_tree if ino_rec is NULL.
> Reported by coverity.
> 
> Signed-off-by: Vivek Trivedi <t.vivek@xxxxxxxxxxx>
> ---
>  repair/phase5.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/repair/phase5.c b/repair/phase5.c
> index 109e37b..5d95e22 100644
> --- a/repair/phase5.c
> +++ b/repair/phase5.c
> @@ -1235,7 +1235,7 @@ build_ino_tree(xfs_mount_t *mp, xfs_agnumber_t agno,
>               if (lptr->modulo > 0)
>                       lptr->modulo--;
>  
> -             if (lptr->num_recs_pb > 0)
> +             if (lptr->num_recs_pb > 0 && ino_rec)
>                       prop_ino_cursor(mp, agno, btree_curs,
>                                       ino_rec->ino_startnum, 0);
>  

Another "can't happen" case. The only time that ino_rec can be zero
is if there are no inodes in the AG, and in that case
init_ino_cursor() initialises lptr->num_recs_pb = 0.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx