[systemd-devel] daemon-reload seems racy

[Colin Guthrie]

'Twas brillig, and Colin Guthrie at 14/01/14 12:10 did gyre and gimble:
> Hi,
> 
> OK, so following on from my posts yesterday about "systemctl
> [en|dis]able weirdness + reload (writes /run/nologin)", I do still seem
> to be getting problems.
> 
> It seems that I got bitten again by this today (tho' not sure what
> triggered it this time).
> 
> 
> The problem simply seems to be that daemon-reload seems to be a bit racy
> generally.
> 
> If two reloads come in in very quick succession, then things go into a
> bad state.


OK, something that's interesting is that I might actually be talking
about daemon-reexec here not just reload.

Certainly the previous log shows a two full-on daemon-reexecs happening.
Problem is I've no idea what is triggering that :s

Nothing I can find in our code has this and nothing in chkconfig or
similar does.

Does anyone know or have any ideas how to track down where the reexec
might be coming from? All the log says is that it's received a
connection on the private bus, which basically means it's come from
systemctl as far as I can tell.

The one that happened today seemed to come from no-where, just some
message about:
Jan 14 11:26:55 jimmy kernel: Not activating Mandatory Access Control as
/sbin/tomoyo-init does not exist.

immediately before. If this is coming from the kernel, could the kernel
actually be triggering this somehow? Perhaps via some telinit compat
layer or something? Is this how things happen? If so what would cause
the kernel to take such action?

Also, could the kernel trigger TWO telinit u's in very quick succession?

Ohhhhhh, interesting... it seems I can trigger the problem just by
running "telinit u; telinit u" in a terminal :)

Looking again, it seems as if "systemctl daemon-reexec; systemctl
daemon-reexec" can also trigger the problem...

Some food for thought.


Col

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Colin Guthrie
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http://colin.guthr.ie/

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