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Message: #07844

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Re: [EP-tech] Apache crashes with a segmentation fault

On Fri, May 17 2019 at 10:16 +00, Newman D.R. wrote:
> Hi Janusz,
> In the past I have noted that running EPrints using Apache's MPM Event
> module rather than Prefork can cause Apache segfault in some scenarios.
>  An update of Debian could have led Apache to switch to MPM Event
> rather than Prefork but you should still be able to use the latter, by
> running:
> a2dismod mpm_event
> a2enmod mpm_prefork
> Then I would advise running:
> apache2ctl configtest
> This will check that the first two commands have not created any
> issues.  Then run apache2ctl restart to restart Apache.  If this does
> not help let me know with any additional log information that you think
> might be useful.  Also, it would be useful to know the versions of
> Debian you were upgrading from and to and the version of Apache you now
> have installed.
> Regards
> David Newman

I enclose the information from Michał:

--8<---------------cut here---------------start------------->8---
1. event/prefork was already in correct state

> a2dismod mpm_event
Module mpm_event already disabled
> a2enmod mpm_prefork
Considering conflict mpm_event for mpm_prefork:
Considering conflict mpm_worker for mpm_prefork:
Module mpm_prefork already enabled

2. Versions
Debian GNU/Linux 9.9 (stretch), up-to-date
ii  apache2             2.4.25-3+deb9u amd64          Apache HTTP Server

3. Log messages
Crash looks like this:
[Fri May 17 12:33:40.883840 2019] [core:notice] [pid 1413] AH00052: child pid 10265 exit signal Segmentation fault

Log after restarting Apache2
[Fri May 17 12:36:49.071303 2019] [mpm_prefork:notice] [pid 1413] AH00169: caught SIGTERM, shutting down
[Fri May 17 12:36:51.673217 2019] [perl:notice] [pid 10447] EPrints archives loaded: teksty, wbl, bc
[Fri May 17 12:36:53.363604 2019] [perl:notice] [pid 10449] EPrints archives loaded: wbl, bc, teksty
[Fri May 17 12:36:53.400144 2019] [mpm_prefork:notice] [pid 10449] AH00163: Apache/2.4.25 (Debian)
mod_wsgi/4.5.11 Python/2.7 mod_perl/2.0.10 Perl/v5.24.1 configured -- resuming normal operations
[Fri May 17 12:36:53.400193 2019] [core:notice] [pid 10449] AH00094: Command line: '/usr/sbin/apache2'
[Fri May 17 12:36:59.050026 2019] [mpm_prefork:notice] [pid 10449] AH00169: caught SIGTERM, shutting down
[Fri May 17 12:37:01.835529 2019] [perl:notice] [pid 10511] EPrints archives loaded: bc, wbl, teksty
This is followed by a long list of crashes like above, one per each web access

--8<---------------cut here---------------end--------------->8---

Best regards


Janusz S. Bien
emeryt (emeritus)