Red Hat Knowledgebase

In Red Hat Enterprise Linux core file creation is disabled by default. This is done by the following ulimit command in /etc/profile:

ulimit -S -c 0 > /dev/null 2>1

There are a couple of ways to enable core file creation. The first is to replace the above ulimit command in /etc/profile with the following:

ulimit -S -c unlimited > /dev/null 2>1

This will allow all users to produce core files of unlimited size.

To disallow users of the system to be able to dump core files, configure the /etc/security/limits.conf file to allow only certain users or groups to create core files. For example, if all the members of the "devel" group are to be allowed to dump core files:

 
#<domain> <type>  <item>  <value>
@devel	 soft	core	<value>

The <value> is the maximum block size of a core file. The /etc/security/limits.conf file is well documented with usage and options at the top of the file. Please note that for these settings to be honored, it is necessary to comment out the above mentioned ulimit command in the /etc/profile file as follows:

 
# No core files by default
# ulimit -S -c 0 > /dev/null 2>1

If this application is being started within its init script with the daemon command, edit the /etc/init.d/functions file to comment out or change this line:

ulimit -S -c 0 >/dev/null 2>1

With this setup, a core file from the application should result. If this does not then make sure that the application has the correct uid and that it does not use setuid to change uid when running. On Red Hat Enterprise Linux 3, use the following command to enable the dumping of setuid applications:

echo 1 > /proc/sys/kernel/core_setuid_ok

Alternatively, add the following call to the application source (in the C language):

prctl(PR_SET_DUMPABLE, 1);

By default, core files are created in the working directory of the faulting application. To override this and specify a location for the files, enter the following command (as root) replacing "/tmp" with the desired target directory:

echo "/tmp" > /proc/sys/kernel/core_pattern