Bug#850074: systemd: "Freezing execution" mode breaks batch upgrades

[Michael Biebl]

Control: retitle -1 systemd crashes on daemon-reexec when /run is full

Am 03.01.2017 um 22:25 schrieb Zack Weinberg:
> On Tue, Jan 3, 2017 at 3:55 PM, Michael Biebl <biebl at debian.org> wrote:
>> Am 03.01.2017 um 21:41 schrieb Zack Weinberg:
> 
>> Hm, yes. It looks like the system (or systemd specifically) was already
>> in a bad state before the daemon-reexec and the crash/freeze was a
>> result of that.
> 
> Indeed.  The problem was /run being full.  Here is a reproduction recipe:
> 
> # cat /dev/zero > /run/eatspace
> cat: write error: No space left on device
> # df -h | grep /run
> tmpfs           128M  128M     0 100% /run
> # apt-get install --reinstall systemd
> Reading package lists... Done
> Building dependency tree
> Reading state information... Done
> 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 3 not upgraded.
> Need to get 0 B/2,453 kB of archives.
> After this operation, 0 B of additional disk space will be used.
> (Reading database ... 269661 files and directories currently installed.)
> Preparing to unpack .../systemd_232-8_amd64.deb ...
> Unpacking systemd (232-8) over (232-8) ...
> Setting up systemd (232-8) ...
> addgroup: The group `systemd-journal' already exists as a system group. Exiting.
> 
> Broadcast message from systemd-journald at kenaz (Tue 2017-01-03 16:16:42 EST):
> 
> systemd[1]: Freezing execution.
> 
> 
> Message from syslogd at kenaz at Jan  3 16:16:42 ...
>  systemd[1]: Freezing execution.
> Failed to try-restart systemd-networkd.service: Connection timed out
> See system logs and 'systemctl status systemd-networkd.service' for details.
> Failed to try-restart systemd-resolved.service: Connection timed out
> See system logs and 'systemctl status systemd-resolved.service' for details.
> Failed to try-restart systemd-timesyncd.service: Connection timed out
> See system logs and 'systemctl status systemd-timesyncd.service' for details.
> Processing triggers for man-db (2.7.6.1-2) ...
> Processing triggers for dbus (1.10.14-1) ...
> Error: Timeout was reached
> 
> And I get the same "Failed to serialize state: Input/output error" in
> the logs.  There is no /core file produced, though.
> 
> I don't know *why* /run was full originally, since it gets cleared on
> reboot, but at a minimum I suggest that systemd.preinst should abort
> the upgrade if /run is full.


Aha, thanks a lot for the reproducer. This helps a lot!

Will forward this issue upstream. daemon-reexec should handle the case
of a full /run more gracefully.

Regards,
Michael

-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

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