[OE-core] [PATCH] oe_syslog.py: Handle syslogd/klogd restart race

[Jon Mason]

On Fri, Jun 21, 2019 at 12:58 PM <richard.purdie at linuxfoundation.org> wrote:
>
> On Fri, 2019-06-21 at 12:39 -0400, Jon Mason wrote:
> > On Fri, Jun 21, 2019 at 12:14 PM Richard Purdie
> > <richard.purdie at linuxfoundation.org> wrote:
> > > On Fri, 2019-06-21 at 11:42 -0400, Jon Mason wrote:
> > > >
> > > Thanks, I think this is reasonable however I think we may need to
> > > make
> > > the above a function and then call it from other places in the
> > > tests in
> > > that file.
> > >
> > > test_syslog_restart should check it did restart using the above
> > >
> > > test_syslog_startup_config does a second restart which we should
> > > also
> > > check?
> >
> > Seems reasonable.  I'll crank out v2 shortly.
> >
> > > Out of interest were you able to see error codes being returned in
> > > status in your tests?
> >
> > I used code to force every error path during development, but not
> > that
> > the testcase will fail.  So, your question did cause me to notice a
> > bug in the code when verifying that the old ones are no longer
> > running.  That should return 0 if still running, which wouldn't cause
> > the assert outside of the loop.  So, I'll need to tweak this there.
> > v2 will have this fix as well.
>
> The reason I ask is that its far from clear that busybox's starts-stop-
> daemon would notice if the daemon didn't restart so I don't think we
> can reliably trust status to be set correctly.
>
> Is there any reason we can't run these checks regardless of status?

The current code logic would work regardless of whether it failed or
not.  I we can run it every time, and it would not hurt anything.

> I realise there is slightly more overhead but it might give us more
> chance of fixing all the races?

4 extra function calls would almost be statistical noise.  I'll code
it up to do the check every time regardless and add it for each
syslogd/klogd call.

>
> Cheers,
>
> Richard
>