[systemd-devel] Possible systemd segfault switching from 216 to 219 in fedora upgrade

[Lennart Poettering]

On Thu, 05.03.15 13:52, James Hogarth (james.hogarth at gmail.com) wrote:

> Hi,
> 
> I spent some time last night trying to track down the issue preventing
> fedup from fedora 21 to 22:
> 
> https://bugzilla.redhat.org/show_bug.cgi?id=1185604
> 
> I'm pretty sure I've tracked it down to when switch-root is called and
> systemd-219 gets executed being passed the serialised state of systemd-216
> in the process.
> 
> Unfortunately when this occurs the whole system is brought to a halt making
> further debugging tricky.
> 
> Any ideas on how I might reproduce on a reduced an BBS simplified testcase
> for the behaviour involved?
> 
> There is strace of pid1 from just before the switch-root to the crash along
> with coredumps that have been generated on the bug.
> 
> These tests were carried out with enforcing=0 at the kernel command line so
> I'm reasonably confident the bug is not SELinux related.

Well, journald is terminated during the switch root transition, since
we want to transition it from the initrd journald to the host
journald, much like PID 1 as well, hence the journal logs end right
before the switch root, making them not particularly useful in this
case.

Right before switch rooting systemd will kill all remaining processes
of the initrd, including the strace, hence the strace logs aren't that
useful either, they end before the transition.

Please boot with "systemd.log_level=debug systemd.log_target=kmsg" on
the kernel cmdline, which ensures the logs go to the kernel log
buffer. And then please provide the output this generates here.

Also see:

http://freedesktop.org/wiki/Software/systemd/Debugging/

Lennart

-- 
Lennart Poettering, Red Hat