On Sat, 30 Mar 2019 08:41:33 -0400
Chas Williams <3ch...@gmail.com> wrote:
> Unfortunately, I think the complete fix is more complicated than this.
> Drivers that use rte_vlan_insert don't anticipate that the mbuf might
> change and that (hardware) transmit can fail.
>
> They make a copy of the mbuf pointer from the incoming transmit list
> and don't update the original if rte_vlan_insert creates a new mbuf.
> If transmit fails, the application needs to be the given the new mbuf
> for re-transmission or freeing.
>
> On 3/28/19 4:53 PM, Stephen Hemminger wrote:
> > If mbuf is shared then rte_vlan_insert() would clobber the original
> > Ethernet header. The changed version handles this by getting
> > an mbuf that will hold the new Ethernet and VLAN header followed
> > by another mbuf (cloned) for the data.
> >
> > Fixes: c974021a5949 ("ether: add soft vlan encap/decap")
> > Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
The virtio driver is buggy, it saves original mbuf and doesn't handle
rewrite. Dpaa2 is fine, should never happen since it checks refcnt etc.
Netvsc PMD is using this on rx path and is safe.
AF_packet PMD should work fine as well.
So virtio is the one that needs fixing
