Child pid ### exit signal Segmentation fault (11) - errors


#1

[size=x-large]Piwik segmentation fault FAQ with solution list now published. Check it out: Troubleshooting - Analytics Platform - Matomo

Hi!

I am using piwik 1.2.1 on a drupal squeeze server. I noticed something strange:
Sometimes, the realtime widget is not working (I can only see the title “Visitor in Real Time” and nothing under it). Other times it is working correctly.

Everytime the “Visitor in Real Time” - widget is not showing any results, I see some of the following errors in my /var/log/apache2/error.log:
[Mon Apr 04 00:36:01 2011] [notice] child pid 4201 exit signal Segmentation fault (11)
[Mon Apr 04 00:36:04 2011] [notice] child pid 4862 exit signal Segmentation fault (11)
[Mon Apr 04 00:36:05 2011] [notice] child pid 4495 exit signal Segmentation fault (11)
[Mon Apr 04 00:36:06 2011] [notice] child pid 4199 exit signal Segmentation fault (11)
[Mon Apr 04 00:36:07 2011] [notice] child pid 4858 exit signal Segmentation fault (11)

I looked at the apache server-status – page (apache module “status”) and all the pids from above handle piwik request:
1-4 4201 6/17/45435 W 2.01 5 0 8.8 0.02 145.46 91.8.176.216 www.example.com GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
3-4 4199 2/13/44131 K 0.98 0 11 1.7 0.03 139.16 91.8.176.216 www.example.com GET /piwik/plugins/SEO/templates/rank.js?cb=d257e5be9602ba080dc
5-4 4495 0/4/43707 W 0.22 5 0 0.0 0.00 138.24 91.8.176.216 www.example.com GET /piwik/index.php?module=Referers&action=getKeywords&idSite=
6-4 4858 4/11/41613 W 1.70 0 0 3.7 0.01 130.41 91.8.176.216 www.example.com GET /piwik/index.php?module=VisitsSummary&action=getEvolutionGr
11-4 4862 0/1/35251 W 0.00 5 0 0.0 0.00 107.79 91.8.176.216 www.example.com GET /piwik/index.php?module=UserCountry&action=getCountry&idSit

I checked my apache error logs and everytime there is a
[notice] child pid XXX exit signal Segmentation fault (11)
the pids belonged to piwik requests

I deactivated the “Visitor in Real Time” - widget for some hours and there were no new errors. Then I activated the “Visitor in Real Time” – widget again and there where new errors.

Has someone an idea what might cause these errors? Is this a problem with piwik or the apache server of Debian Squeeze, or …?


(vipsoft) #2

Any segfault in php would be a bug in php (not Piwik).

Try disabling any third party php mods/extensions like suhosin and eaccelerator.

You could also try recompiling php with --enable-debug, and enable core dumps. From there, you could use a debugger (eg gdb) to get a backtrace and then report it to the php devs.


#3

Hello vipsoft.

Thanks for your answer. I think I will just deactivate the “Visitor in Real Time” – widget. It’s not so important and when it’s deactivated, there a no new errors in my logs.

I think it’s the best solution for me, because I never compiled php myself (I only used the php package over debian aptitude). Also I don’t want to make so many changes to a otherwise stable and good-working server-configuration.

Some information about the other extensions you wrote about:

  • I do not use eaccelerator. But I use APC (Alternative PHP Cache). Deactivating it, I still see the error messages.
  • The Suhosin Patch 0.9.9.1 is part of the debian standard installation. Deactivating it, I still see the error messages.

(vipsoft) #4

Thanks for trying.

I don’t know the specifics of the Debian squeeze build for php, but if you’re not using the latest version, there is a fix for a PDO_MySQL segfault in php 5.3.6.


(Matthieu Aubry) #5

See the RC: 301 Moved Permanently


#6

@matt

I have installed and tested the new Piwik 1.2.5-rc2. It seems that the problems have gotten bigger :wink:

Everytime the 3 following things happen, I now have 9 exit signal Segmentation faults in my apache logs (with piwik 1.2.1 there were only 5):

  1. The <Live! – Visitor in Real Time> - widget is activated and shown on the frontpage
  2. The frontpage of piwik is loaded
  3. The <Live! – Visitor in Real Time> - widget does not show any results
    If 1+2+3 do not happen, my system is completly error free.

Apache log:
[Tue Apr 05 19:27:51 2011] [notice] child pid 16446 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:51 2011] [notice] child pid 16474 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:52 2011] [notice] child pid 16447 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:52 2011] [notice] child pid 16472 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:53 2011] [notice] child pid 16444 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:53 2011] [notice] child pid 16467 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:53 2011] [notice] child pid 16475 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:54 2011] [notice] child pid 16445 exit signal Segmentation fault (11)
[Tue Apr 05 19:27:54 2011] [notice] child pid 16473 exit signal Segmentation fault (11)

Apache Status:
2-18 16446 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
3-18 16474 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
4-18 16467 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
8-18 16444 GET /piwik/index.php?module=VisitTime&action=getVisitInformatio
9-18 16447 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
11-18 16472 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
12-18 16445 GET /piwik/libs/open-flash-chart/open-flash-chart.swf?piwik=1.2
13-18 16473 GET /piwik/index.php?module=Live&action=widget&idSite=1&period=
14-18 16475 GET /piwik/index.php?module=VisitsSummary&action=getEvolutionGr


(vipsoft) #7

Can you try switching to MYSQLI in config/config.ini.php?


adapter=MYSQLI


#8

It seems that I also have some problems with the live plugin.

I had lots of exit signal Segmentation faults lately and did not know where they came from. Reading this forum post I checked to see if piwik might be the cause. And it definitely is!

I have the frontpage with the live-plugin opened. Everytime a new visitor pops up in the live plugin I get one new exit signal Segmentation fault in my logs.

The only solution so far is to deactivate the live plugin.

System information:
Debian Squeeze LAMP installation
Piwik 1-2-1


#9

As recommended by Anthon, I changed adapter from PDO_MYSQL to MYSQLI. Things have got much better:

  • The “Visitors in Real Time” – widget is now always showing results
  • The “[notice] child pid ##### exit signal Segmentation fault (11)” errors have gotten much less
  • The “[notice] child pid ##### exit signal Segmentation fault (11)” errors have changed: They are now extremely seldom when opening the page, but now there is one error for each new visitor that gets shown in the “Visitors in Real Time” – widget (as long as this widget runs on auto-mode or the page is opened)

(vipsoft) #10

That’s an encouraging sign. Debian’s php5 packages are currently 5.3.3 with some backported security fixes. But 5.3.6 fixes a number of bugs (including segfaults).


#11

I just wanted to inform you that with Piwik 1.2.5-rc8 the “[notice] child pid ##### exit signal Segmentation fault (11)” - errors are now completely gone.


(Matthieu Aubry) #12

I don’t know why, but that’s good news!


(Matthieu Aubry) #13

Piwik segmentation fault FAQ with solution list now published. Check it out: Troubleshooting - Analytics Platform - Matomo