Into.the.Void.

Today I had a very unpleasant surprise with my Vodafone Mobile Connect on Mac OS X. After a normal laptop standby, the application refused to open. Upon starting the application it peaked at 100% cpu usage but no gui ever appeared. I had to kill the application after a while…No messages at the console either. The solution was to (re)move the /Library/Application Support/nova media and /Library/Application Support/Vodafone folders to another location.

This way you lose your stats (data transfered, time used) but at least you can get back on the net…pheeeewwww

Filed by kargig at 20:37 under Internet,MacOSX,Networking
2 Comments | 6,811 views

Debian is one of the few distros that you can’t search the bash history backward or forward for past commands by default.
To change that behaviour you need to uncomment two lines inside /etc/inputrc.

Change:

# alternate mappings for "page up" and "page down" to search the history
# "\e[5~": history-search-backward
# "\e[6~": history-search-forward

To:

# alternate mappings for "page up" and "page down" to search the history
"\e[5~": history-search-backward
"\e[6~": history-search-forward


Example usage:
To search through your old commands that started with “ssh” (e.g. ssh -p 551 koko@lala.gr, ssh foo@bar.gr, ssh test@koko.gr -L1111:1.2.3.4:9876), just type ssh and hit PgUp, you will see the previous ssh commands appearing on the command line.
$ ssh[PgUp] transforms to $ ssh -p 551 koko@lala.gr hit PgUp again and it transforms to
$ ssh foo@bar.gr PgUp and it becomes $ ssh test@koko.gr -L1111:1.2.3.4:9876

Filed by kargig at 12:06 under Linux
6 Comments | 8,810 views

Dear Internet,

I need your help!
I have a debian stable (4.0) server with apache2 (Version: 2.2.3-4+etch6) running which is hosting more than 10 different sites. The problem is that in the apache2 error log I can see a lot of segfaults. All sites though continue to work properly and nobody has ever complained about them.

Some logs:

[Tue Feb 03 18:30:36 2009] [notice] child pid 1353 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:37 2009] [notice] child pid 29343 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:37 2009] [notice] child pid 1350 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:38 2009] [notice] child pid 1349 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:38 2009] [notice] child pid 1352 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:39 2009] [notice] child pid 1354 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:41 2009] [notice] child pid 1380 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:42 2009] [notice] child pid 1378 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:42 2009] [notice] child pid 1714 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:44 2009] [notice] child pid 1715 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:44 2009] [notice] child pid 1718 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:45 2009] [notice] child pid 1720 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:45 2009] [notice] child pid 1721 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:46 2009] [notice] child pid 1723 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:47 2009] [notice] child pid 1724 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:47 2009] [notice] child pid 1725 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:49 2009] [notice] child pid 1726 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:49 2009] [notice] child pid 1728 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:50 2009] [notice] child pid 1729 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:50 2009] [notice] child pid 1730 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:51 2009] [notice] child pid 1358 exit signal Segmentation fault (11)
[Tue Feb 03 18:30:51 2009] [notice] child pid 1733 exit signal Segmentation fault (11)

In order to find out what causes the segfaults I have enabled the following options:
inside /etc/apache2/apache2.conf
CoreDumpDirectory /tmp-apache/
$ ls -Fla / | grep tmp-apache
drwxrwxrwx 2 www-data www-data 4096 2009-01-31 11:01 tmp-apache/

I have changed the ulimit settings inside /etc/security/limits.conf
* soft core unlimited
* hard core unlimited

I have even added a ulimit -c unlimited setting inside /etc/init.d/apache2.
But still I get no core dumps inside /tmp-apache2/ from the segfaulting children.
If I manually kill -11 apache.pid then I can see a core file inside /tmp-apache/

I have only seen one or two core dumps generated by apache and using gdb I could see that they both “blamed” a function of /usr/lib/apache2/modules/libphp5.so. In my quest to find which site/code causes the segfaults I have recompiled apache2 to enable mod_whatkilledus. But no core dump was created in /tmp-apache/ for more than a week even if the segfaults keep happening.

I have reduced my modules, removed mod_python, mod_perl, etc and still these segfaults keep occuring but no core dumps. I suspect that the only time I got a core was when a parent and not a child process segfaulted. I don’t think that my apache2 children dump core when they segfault.

Is there anything I could have done and I haven’t done it ? Is there a way I can force apache2 children to dump core or any other way to determine what causes these segfaults ? All these without of course closing down the sites one by one to see when the segfaults stop…

Thanks in advance to anyone that replies!

P.S. blog’s database is making some tricks…I hope it’s ok now and the post is fully published

Filed by kargig at 22:41 under Linux
14 Comments | 17,149 views