The mbufs should also be restored in free_zmbufs().
Fixes: b0a985d1f340 ("vhost: add dequeue zero copy")
Fixes: 3ebd930588b7 ("vhost: fix mbuf free")
Cc: stable@dpdk.org
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>