Subject: 4.4-rc7 failure report

From: Doug Ledford <[email-masked]>
Date: Mon, 28 Dec 2015 16:53:45 -0500

Hi Dave,

The 4.4-rc7 kernel is failing for me.  In my case, all of my vlan
interfaces are failing to obtain a dhcp address using dhclient.  I've
tried a hand built 4.4-rc7, and the Fedora rawhide 4.4-rc7 kernel, both
failed.  I've tried NetworkManager and the old SysV network service,
both fail.  I tried a working dhclient from rhel7 on the Fedora rawhide
install and it failed too.  Running tcpdump on the interface shows the
dhcp request going out, and a dhcp response coming back in.  Running
strace on dhclient shows that it writes the dhcp request, but it never
recvs a dhcp response.  If I manually bring the interface up with a
static IP address then I'm able to run typical IP traffic across the
link (aka, ping).  It would seem that when dhclient registers a packet
filter on the socket, that filter is preventing it from ever getting the
dhcp response.  The same dhclient works on any non-vlan interfaces in
the system, so the filter must work for non-vlan interfaces.  Aside from
the fact that the interface is a vlan, we also use a priority egress map
on the interface, and we use PFC flow control.  Let me know if you need
anymore to debug the issue, or email me off list and I can get you
logins to my reproducer machines.

-- 
Doug Ledford <[email-masked]>
              GPG KeyID: 0E572FDD