Re: [PATCH] nfsd: only unhash DRC entries that are in the hashtable

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Mar 18, 2013 at 10:49:07AM -0400, Jeff Layton wrote:
> It's not safe to call hlist_del() on a newly initialized hlist_node.
> That leads to a NULL pointer dereference. Only do that if the entry
> is hashed.

Thanks!  Applying for 3.9.--b.

> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/nfsd/nfscache.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
> index f5ad28e..ca05f6d 100644
> --- a/fs/nfsd/nfscache.c
> +++ b/fs/nfsd/nfscache.c
> @@ -102,7 +102,8 @@ nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
>  {
>  	if (rp->c_type == RC_REPLBUFF)
>  		kfree(rp->c_replvec.iov_base);
> -	hlist_del(&rp->c_hash);
> +	if (!hlist_unhashed(&rp->c_hash))
> +		hlist_del(&rp->c_hash);
>  	list_del(&rp->c_lru);
>  	--num_drc_entries;
>  	kmem_cache_free(drc_slab, rp);
> -- 
> 1.7.11.7
>