Bug#795970: systemd is a ridiculous tentacled mess that breaks the rest of the system when it inevitably falls over

[Tim Connors]

On Thu, 20 Aug 2015, Martin Pitt wrote:

> Hello,
>
> this is a conflation of a pointless rant (in the subject),
> X.org/graphics driver problems without any details, and swapspace.
> There are no actionable items here, thus I close this.
>
> Please have a look at dmesg, this almost surely sounds like a kernel
> or driver problem that causes half of userspace to lock up. "D" is
> "uninterruptible kernel sleep" indicating that a read() or similar
> operation hangs forever in the kernel.
>
> It might also be related to swapspace trying to swap out memory to a
> terribly slow disk. Either way, not a systemd problem.

To quote Brian May on a local LUG mailing list:

==========
Note this error happened in the unpacking phase, not the configuration
phase. So I think it is unlikely dpkg has even looked at swapspace'
postinst at this point.

Also note the previous line is "Processing triggers for systemd".

I note that swapspace doesn't have a preinst script.

So I would speculate the problem is in the systemd trigger.

(this being complicated so far has nothing to do with systemd, but rather
the design of dpkg)

Looking at /var/lib/dpkg/info/systemd.postinst I would speculate the
trigger being called is after /etc/init.d is updated, it calls "systemctl
daemon-reload" via a wrapper that checks /run/systemd/system exists first.

The only time I have seen this happen myself is when systemd was already
broken, because the kernel was too old and didn't have the required
features.

Possibly nothing wrong with the kernel here, however I have to wonder if
systemd was already broken for some reason. Maybe it failed to start up
correctly because something else was broken.


-- 
Tim Connors