Bug#923398: In debian stretch: bind(2) port collision checking is wrong for IPv4 if IPv6 is checked first

[Katerina Koukiou <kkoukiou@redhat.com>]

Package: linux-headers-4.9.0-8-amd64

I hit into the following bug when creating two VMs with virt-manager
configured with spice server. I started them sequentially, first
starts but the second fails to spawn with error:

Error starting domain: internal error: qemu unexpectedly closed the monitor:
(process:7985): Spice-WARNING **: reds.c:2577:reds_init_socket:
listen: Address already in use
2017-03-15T23:57:46.288270Z qemu-system-x86_64: failed to initialize
spice server

While searching for open bugs about it I found out that it was a
kernel bug, which was fixed in kernel-4-13, later than what debian
stretch has.

The main upstream kernel fix seems to be:

commit cbb2fb5c72f48d3029c144be0f0e61da1c7bccf7
Author: Josef Bacik <jbacik@fb.com>
Date:   Fri Sep 22 20:20:06 2017 -0400

    net: set tb->fast_sk_family

This is not included in 4.9 kernel of debian stretch ,
# uname -ra
Linux unassigned-hostname 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1
(2019-02-19) x86_64 GNU/Linux

Maybe it is worth to backport it.

Thanks,
Katerina