Re: [dpdk-stable] [PATCH] vhost: fix accessing uninitialized variables

["Liu, Yong" <yong.liu@intel.com>]

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: Tuesday, April 6, 2021 2:18 PM
> To: Liu, Yong <yong.liu@intel.com>; maxime.coquelin@redhat.com
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: RE: [PATCH] vhost: fix accessing uninitialized variables
> 
> Hi Marvin,
> 
> > -----Original Message-----
> > From: Liu, Yong <yong.liu@intel.com>
> > Sent: Wednesday, March 3, 2021 3:28 PM
> > To: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
> > Cc: dev@dpdk.org; Liu, Yong <yong.liu@intel.com>; stable@dpdk.org
> > Subject: [PATCH] vhost: fix accessing uninitialized variables
> >
> > This patch fixs coverity issue by adding initialization step before
> > using temporary virtio header.
> >
> > Coverity issue: 366181, 366123
> > Fixes: fb3815cc614d ("vhost: handle virtually non-contiguous buffers in Rx-
> > mrg")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Marvin Liu <yong.liu@intel.com>
> >
> > diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> > index 583bf379c6..fe464b3088 100644
> > --- a/lib/librte_vhost/virtio_net.c
> > +++ b/lib/librte_vhost/virtio_net.c
> > @@ -808,9 +808,10 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct
> > vhost_virtqueue *vq,
> 
> You should apply the same fix to async_mbuf_to_desc.
> Maybe you did not notice: one coverity issue is in copy_mbuf_to_desc, but
> another
> in async_mbuf_to_desc :)
> 
Thanks for remind, will fix function async_mbuf_to_desc in next version.

Regards,
Marvin

> Thanks,
> Chenbo
> 
> >
> >  hdr_mbuf = m;
> >  hdr_addr = buf_addr;
> > -if (unlikely(buf_len < dev->vhost_hlen))
> > +if (unlikely(buf_len < dev->vhost_hlen)) {
> > +memset(&tmp_hdr, 0, sizeof(struct virtio_net_hdr_mrg_rxbuf));
> >  hdr = &tmp_hdr;
> > -else
> > +} else
> >  hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
> >
> >  VHOST_LOG_DATA(DEBUG, "(%d) RX: num merge buffers %d\n",
> > --
> > 2.17.1
>