Bug#758808: udev: time out issue after wheezy->jessie upgrade

[Detrich Bertalan]

> Control: tags -1 moreinfo unreproducible
>
> Hi
>
> Am 02.03.2016 um 16:24 schrieb detbe:
>> I upgraded a several machnies from wheezy to jessie. After the upgrade the first boot was successfull, but sometimes later the boot hangs on "A start job is running..".
> Which job exactly was it waiting for? For how long?
5 jobs in infinite cycle the following order:

Starting udev Kernel Device manager...

A start job is running for..

.. udev Kernel Device Manager
.. dev-mapper-vg-name
.. Apply Kernel Variables
.. dev-disk-by-
.. udev Wait for Complete Device Initialization


>
> Can you follow the instructions at [1] and enable a debug shell on tty9.
> Boot with systemd.log_level=debug
> switch to tty9, store the output of
> systemctl list-jobs
> and
> journalctl -alb
> and attach those files to the but report.
>
>
The emergency shell not working, no answer after typed systemctl or 
journalctl


>> I try to find what systemd processes running on infinite cycle. Found the systemd-udevd.service, systemd-udev-settle.service, lvm2-activation service. I suspected that the lvm2 service started before the udev process finish. I try to find the right bootup order to this services: systemd.udevd.service -> systemd-udev-settle.service -> lvm2-activation.service . Every process have to finish, before the next one started.
>> Then i edit this services "Before=" lines to force the successfull exit before the next start.
>> After many successful boot, finally i try to find out what the exactly missing option. (Only one needed)
>>
>> Here is the diff: (working dir /lib/systemd/system/)
>>
>> diff --git a/systemd-udevd.service b/systemd-udevd.service
>> index 51497ce..eea7178 100644
>> --- a/systemd-udevd.service
>> +++ b/systemd-udevd.service
>> @@ -11,7 +11,7 @@ Documentation=man:systemd-udevd.service(8) man:udev(7)
>>   DefaultDependencies=no
>>    Wants=systemd-udevd-control.socket systemd-udevd-kernel.socket
>>     After=systemd-udevd-control.socket systemd-udevd-kernel.socket systemd-udev-hwdb-update.service systemd-sysusers.service
>>     -Before=sysinit.target
>>     +Before=sysinit.target systemd-udev-settle.service
> That ordering should not be necessary.
> systemd-udev-settle.service has After=systemd-udev-trigger.service which
> has After=systemd-udevd-kernel.socket systemd-udevd-control.socket
Yes, i see that, but the reboot issue solved when i added the 
systemd-udevd.service before the systemd-udev-settle.service
>
> [1] https://freedesktop.org/wiki/Software/systemd/Debugging/