Re: [dpdk-dev] [PATCH] virtio: fix buffer leak on vlan insert

[Jens Freimann]

On Thu, Apr 04, 2019 at 05:03:43PM -0700, Stephen Hemminger wrote:
The function rte_vlan_insert may allocate a new buffer for the
vlan header and return a different mbuf than originally passed.
In this case, the stored mbuf in txm[] array could point to wrong
buffer.
Fixes: dd856dfcb9e7 ("virtio: use any layout on Tx")
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
drivers/net/virtio/virtio_rxtx.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index e6f3706d6fe1..2ae4232c181d 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -2003,6 +2003,8 @@ virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf 
**tx_pkts,
                                rte_pktmbuf_free(txm);
                                continue;
                        }
+                       /* vlan_insert may add a header mbuf */
+                       tx_pkts[nb_tx] = txm;
                }

                /* optimize ring usage */

Good catch. I think we have the same bug in virtio_xmit_pkts() and
virtio_xmit_pkts_inorder() and should fix these as well. 


Thanks!

regards,
Jens