Apache crashes with glibc detected and stack trace

[Paul Vaughan]

Binary package hint: apache2

Expected behaviour: no problems, Apache to serve web pages for the college's VLE.

Actual behaviour: very slow serving pages for ~30 seconds, /var/log/apache2/error.log shows:

*** glibc detected *** /usr/sbin/apache2: double free or corruption (fasttop): 0x00007f3f1dd0dd50 ***

...followed by a backtrace (file file attached).

I have reported this bug before but was unable to reproduce. It has now returned but I am unable to locate the previously filed bug so cannot recall what steps to take now.

$ lsb_release -rd
Description: Ubuntu 10.04.1 LTS
Release: 10.04

$ apt-cache policy apache2
apache2:
  Installed: 2.2.14-5ubuntu8.2
  Candidate: 2.2.14-5ubuntu8.3
  Version table:
     2.2.14-5ubuntu8.3 0
        500 http://gb.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
 *** 2.2.14-5ubuntu8.2 0
        500 http://security.ubuntu.com/ubuntu/ lucid-security/main Packages
        100 /var/lib/dpkg/status
     2.2.14-5ubuntu8 0
        500 http://gb.archive.ubuntu.com/ubuntu/ lucid/main Packages

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: apache2 2.2.14-5ubuntu8.2
ProcVersionSignature: Ubuntu 2.6.32-21.32-server 2.6.32.11+drm33.2
Uname: Linux 2.6.32-21-server x86_64
Architecture: amd64
Date: Tue Nov 16 11:36:21 2010
InstallationMedia: Ubuntu-Server 10.04 LTS "Lucid Lynx" - Release amd64 (20100427)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: apache2

[Mathias Gug (mathiaz)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that apache2 crashes because of a php script. Could you attach a php script that reproduce the crash?

[Paul Vaughan (paulieboo)]

Hi Mathias.

You are correct, the server runs PHP scripts, but as part of the open source VLE Moodle: http://moodle.org/

Moodle is a complex application and I would have no idea what aspect of it might have caused apache to crash. I develop code for Moodle, but plugins only, I have little to do with the core code. The only thing I can think of is that I can look at Apache's other_vhosts_access.log on the server and try to work out what Moodle was doing at that time, or a few minutes before. I will do this tomorrow as I am not able to access the logs right now.

[Paul Vaughan (paulieboo)]

In Apache's error.log, the error happened at some point between 10:00:39 and 10:01:18, so I have included a much-reduced access.log with all PHP files executed between those time points on that day, appropriately sanitised. Hopefully it will prove useful.

[Paul Vaughan (paulieboo)]

It may be worth mentioning that I filed a very similar bug to this one within the last month or so, but as it was closed as 'cannot reproduce' or similar and I cannot locate it to link to. It definitely had 'glibc' in the title of the report.

[Launchpad Janitor (janitor)]

[Expired for apache2 (Ubuntu) because there has been no activity for 60 days.]