Bug#682264: #682264, libapache2-mod-perl2: Crash at server startup when pre-loading Plack app

[Dominic Hargreaves]

On Fri, Sep 01, 2017 at 10:33:38AM +0100, Dominic Hargreaves wrote:
> On Fri, Sep 01, 2017 at 03:47:57PM +1000, Dmitry Smirnov wrote:
> > I had the same problem until I've realised that Apache now uses event module
> > by default. Solution is simple -- just switch to (traditional) MPM Prefork
> > model as follows:
> > 
> > ~~~~
> > a2dismod mpm_event
> > a2enmod mpm_prefork
> > ~~~~
> 
> Hi Dmitry,
> 
> Thanks for pointing this out. And to the original submitter, I'm sorry
> that there was no reply on this bug before in many years!
> 
> As far as I know from a quick bit of digging it is indeed the case
> that mod_perl will not work with the event mpm, so we should
> arrange for it to either not be possible to load it it in that
> configuration, or at least to print dire warnings if that happens
> (which may be safer in any case).
> 
> I will try and have a look at this at some point but it might not be
> soon, so help would be appreciated.
> 
> FTR, Red Hat does the same thing:
> <https://bugzilla.redhat.com/show_bug.cgi?id=1059225>.

I asked Jan Kaluza (the Redhat contact) if the Redhat fix could be
shared, as I couldn't find that change anywhere online. No response
yet. Maybe someone more familiar with the Redhat ecosystem could dig it up?

Cheers,
Dominic.