Re: [dpdk-dev] [PATCH v2] enic: fix seg fault when releasing queues

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, May 25, 2016 at 07:45:00PM -0700, John Daley wrote:
> If device configuration failed due to a lack of resources, like if
> there were more queues requested than available, the queue release
> function is called with NULL pointers which were being dereferenced.
> 
> Skip releasing queues if they are NULL pointers. Also, if configuration
> fails due to lack of resources, be more specific about which resources
> are lacking.

The "also", and a a review of the code, indicates that the error message
changes should be a separate patch, as it's not related to the NULL check fix.
:-)


> 
> Fixes: fefed3d1e62c ("enic: new driver")
> Signed-off-by: John Daley <johndale@cisco.com>
> ---
> v2: Log an error for all resource deficiencies not just the first one
> found.
> 
>  drivers/net/enic/enic_main.c | 37 +++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c
> index 996f999..411d23c 100644
> --- a/drivers/net/enic/enic_main.c
> +++ b/drivers/net/enic/enic_main.c
> @@ -426,14 +426,16 @@ int enic_alloc_intr_resources(struct enic *enic)
>  
>  void enic_free_rq(void *rxq)
>  {
> -	struct vnic_rq *rq = (struct vnic_rq *)rxq;
> -	struct enic *enic = vnic_dev_priv(rq->vdev);
> +	if (rxq != NULL) {
> +		struct vnic_rq *rq = (struct vnic_rq *)rxq;
> +		struct enic *enic = vnic_dev_priv(rq->vdev);
>  
> -	enic_rxmbuf_queue_release(enic, rq);
> -	rte_free(rq->mbuf_ring);
> -	rq->mbuf_ring = NULL;
> -	vnic_rq_free(rq);
> -	vnic_cq_free(&enic->cq[rq->index]);
> +		enic_rxmbuf_queue_release(enic, rq);
> +		rte_free(rq->mbuf_ring);
> +		rq->mbuf_ring = NULL;
> +		vnic_rq_free(rq);
> +		vnic_cq_free(&enic->cq[rq->index]);
> +	}
>  }

Is it not just easier to put a check at the top for: 
	if (rq == NULL)
		return;

Rather than putting the whole body of the function inside an if statement? It
would certainly be a smaller diff.

/Bruce