From mboxrd@z Thu Jan  1 00:00:00 1970
From: "John Daley (johndale)" <johndale@cisco.com>
Subject: Re: [PATCH] enic: check for nb_free > 0
Date: Wed, 2 Aug 2017 18:34:53 +0000
Message-ID: <1a29ffbed0e442798d0e29b5af90f1fc@XCH-RCD-007.cisco.com>
References: <20170802180213.28736-1-aconole@redhat.com>
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Cc: "stable@dpdk.org" <stable@dpdk.org>, Bruce Richardson
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To: Aaron Conole <aconole@redhat.com>, "dev@dpdk.org" <dev@dpdk.org>
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> -----Original Message-----
> From: Aaron Conole [mailto:aconole@redhat.com]
> Sent: Wednesday, August 02, 2017 11:02 AM
> To: dev@dpdk.org
> Cc: stable@dpdk.org; John Daley (johndale) <johndale@cisco.com>; Bruce
> Richardson <bruce.richardson@intel.com>
> Subject: [PATCH] enic: check for nb_free > 0
>=20
> Occasionally, the amount of packets to free from the work queue ends
> perfectly on a boundary to have nb_free =3D 0 and pool =3D 0.  This cause=
s a
> segfault as follows:
>=20
>   (gdb) bt
>   #0  rte_mempool_default_cache (mp=3D<optimized out>, mp=3D<optimized
> out>,
>       lcore_id=3D<optimized out>)
>       at /usr/src/debug/openvswitch-2.6.1/dpdk-16.11/x86_64-native-
> linuxapp-gcc/include/rte_mempool.h:1017
>   #1  rte_mempool_put_bulk (n=3D0, obj_table=3D0x7f10deff2530, mp=3D0x0)
>       at /usr/src/debug/openvswitch-2.6.1/dpdk-16.11/x86_64-native-
> linuxapp-gcc/include/rte_mempool.h:1174
>   #2  enic_free_wq_bufs (wq=3Dwq@entry=3D0x7efabffcd5b0,
>       completed_index=3Dcompleted_index@entry=3D33)
>       at /usr/src/debug/openvswitch-2.6.1/dpdk-
> 16.11/drivers/net/enic/enic_rxtx.c:429
>   #3  0x00007f11e9c86e17 in enic_cleanup_wq (enic=3D<optimized out>,
>       wq=3Dwq@entry=3D0x7efabffcd5b0)
>       at /usr/src/debug/openvswitch-2.6.1/dpdk-
> 16.11/drivers/net/enic/enic_rxtx.c:442
>   #4  0x00007f11e9c86e5f in enic_xmit_pkts (tx_queue=3D0x7efabffcd5b0,
>       tx_pkts=3D0x7f10deffb1a8, nb_pkts=3D<optimized out>)
>       at /usr/src/debug/openvswitch-2.6.1/dpdk-
> 16.11/drivers/net/enic/enic_rxtx.c:470
>   #5  0x00007f11e9e147ad in rte_eth_tx_burst (nb_pkts=3D<optimized out>,
>       tx_pkts=3D0x7f10deffb1a8, queue_id=3D0, port_id=3D<optimized out>)
>=20
> This commit makes the enic wq driver match other drivers who call the bul=
k
> free, by checking that there are actual packets to free.
>=20
> Fixes: 36935afbc53c ("net/enic: refactor Tx mbuf recycling")
> CC: stable@dpdk.org
> Reported-by: Vincent S. Cojot <vcojot@redhat.com>
> Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=3D1468631
> Signed-off-by: Aaron Conole <aconole@redhat.com>
> ---
>  drivers/net/enic/enic_rxtx.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/net/enic/enic_rxtx.c b/drivers/net/enic/enic_rxtx.c =
index
> 5867acf..a39172f 100644
> --- a/drivers/net/enic/enic_rxtx.c
> +++ b/drivers/net/enic/enic_rxtx.c
> @@ -503,7 +503,8 @@ static inline void enic_free_wq_bufs(struct vnic_wq
> *wq, u16 completed_index)
>  		tail_idx =3D enic_ring_incr(desc_count, tail_idx);
>  	}
>=20
> -	rte_mempool_put_bulk(pool, (void **)free, nb_free);
> +	if (nb_free > 0)
> +		rte_mempool_put_bulk(pool, (void **)free, nb_free);
>=20
>  	wq->tail_idx =3D tail_idx;
>  	wq->ring.desc_avail +=3D nb_to_free;
> --
> 2.9.4

Reviewed-by: John Daley <johndale@cisco.com>

Thank you!

johnd