Bug#837759: network configuration stops working reliably

[Felipe Sateler]

On 14 September 2016 at 18:34, Wolfgang Walter <wolfgang.walter at stwm.de> wrote:
> On Wednesday, 14 September 2016 10:00:28 CEST Felipe Sateler wrote:
>> Control: tags -1 moreinfo
>>
>> On 14 September 2016 at 06:59, Wolfgang Walter <wolfgang.walter at stwm.de> wrote:
>> > Package: systemd
>> > Version: 231-6
>> > Severity: grave
>> >
>> > Starting with version 231-6 the configuration of network interfaces stops
>> > working reliably when rebooting a system. Downgrading to 231-5 fixes the
>> > problem.
>> >
>> > Symptoms: If a network interface is configured using
>> > /etc/network/interfaces it seems that systemd now sometimes removes the
>> > configured ip4 and/or ipv6 addresses in the boot process. It also seems
>> > to remove routes of network interfaces configured manually or with
>> > /etc/network/interfaces if the link state changes.
>> >
>> > This seems not only be the case with interfaces configured via
>> > /etc/network/ interfaces but with any interface one creates and assigns
>> > ip addresses manually.
>> >
>> > I tested this with a script:
>> >
>> > #!/bin/sh
>> > if [ "$1" = start ]; then
>> > ip link del TEST >/dev/null 2>&1 || true
>> > ip link add name TEST type dummy
>> > ip -b - <<"EOF"
>> > link set TEST up
>> > addr add 10.10.10.10/32 dev TEST nodad
>> > addr add 2a01:1:1:1::1/128 dev TEST nodad
>> > addr add 2a01:1:1:1::2/128 dev TEST nodad
>> > addr add 2a01:1:1:1::3/128 dev TEST nodad
>> > addr add 2a01:1:1:1::4/128 dev TEST nodad
>> > addr add 2a01:1:1:1::5/128 dev TEST nodad
>> > EOF
>> > ip addr ls TEST
>> > sleep 2
>> > elif [ "$1" = stop ]; then
>> > ip addr flush dev TEST
>> > ip link del TEST
>> > fi
>> >
>> > which I start with as a systemd oneshot service with
>> >
>> >         Before=systemd-networkd.service
>> >
>> > I can see in the journal that TEST has all adresses assigned but with
>> > 231-6 it looses them again (probably when systemd-networkd.service
>> > starts). With 231-5 or earlier this in not the case.
>>
>> It appears you are using systemd-networkd. Could you please attach
>> your networkd configuration?
>>
>> Version 231-6 is built with iptables support, so that may be causing
>> an interaction that was not visible before.
>
> I think this is the problem:
>
> https://anonscm.debian.org/cgit/pkg-systemd/systemd.git/commit/?h=debian/231-6&id=79e10aaee1cdd412bd42f13f26e558ba1cd2196b
>
> I suppose is that the check for LINK_STATE_UNMANAGED may be racy.
> The interface may go down and up before LINK_STATE_UNMANAGED is set.
> Maybe the state is LINK_STATE_PENDING ?

Interesting. Did you test with that patch disabled? (sorry, I have not
had time to test).

-- 

Saludos,
Felipe Sateler