Question

I keep getting this log entries on ubuntu 10.04 lts:

# vim /var/log/apache2/error.log

[Sun Mar 18 08:58:01 2012] [notice] child pid 4300 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:02 2012] [notice] child pid 4302 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:03 2012] [notice] child pid 4303 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:03 2012] [notice] child pid 4304 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:04 2012] [notice] child pid 4305 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:04 2012] [notice] child pid 4306 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:04 2012] [notice] child pid 4307 exit signal Segmentation fault (11)
[Sun Mar 18 08:58:04 2012] [notice] child pid 4308 exit signal Segmentation fault (11)

I added coredumps to my httpd.conf:

CoreDumpDirectory /tmp/apache2-gdb-dump

created, chmod 777 and chown www-data:www-data the tmp/apache2-dgb-dump, set

# ulimit -c unlimited

and restarted apache.
The Coredump is created and I tried to analyze it, but it does not tell me anything…:

# gdb /etc/init.d/apache2 core
GNU gdb (GDB) 7.1-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
"/etc/init.d/apache2": not in executable format: File format not recognized
[New Thread 7968]
Core was generated by `/usr/sbin/apache2 -k start'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f78121f36ad in ?? ()
(gdb) where
#0  0x00007f78121f36ad in ?? ()
#1  0x00007f7800000002 in ?? ()
#2  0x00007f78044af088 in ?? ()
#3  0x00007f7815e86080 in ?? ()
#4  0x00007f7816e5b5e8 in ?? ()
#5  0x00007f7816ed2a10 in ?? ()
#6  0x00007f7815e86080 in ?? ()
#7  0x00007f7815e86080 in ?? ()
#8  0x00007f78129058c0 in ?? ()
#9  0x00007f7816ed2a10 in ?? ()
#10 0x00007f781223614c in ?? ()
#11 0x00007f7815e86080 in ?? ()
#12 0x00007f7812235ee0 in ?? ()
#13 0x0000000000000006 in ?? ()
#14 0x00007f7816a251d0 in ?? ()
#15 0x00007f7816d38a40 in ?? ()
#16 0x01007fff69cdd3c0 in ?? ()
#17 0x00007fff69cdd3c0 in ?? ()
#18 0x00007f78129058c0 in ?? ()
#19 0x00007fff69cdd3c0 in ?? ()
#20 0x0000000000000001 in ?? ()
#21 0x0000000000000000 in ?? ()

What can I do to find out what the problem is?

Answer 1

You are invoking gdb in a wrong way. According to gdb output, core dump was generated by /usr/sbin/apache2. You should run gdb like this: gdb /usr/sbin/apache2 core. /etc/init.d/apache2 is, most likely, some script invoking /usr/sbin/apache2. See gdb output:

"/etc/init.d/apache2": not in executable format: File format not recognized
[New Thread 7968]
Core was generated by `/usr/sbin/apache2 -k start'.
Program terminated with signal 11, Segmentation fault.