How to enable core file dumps when an application crashes or segmentation faults

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 4
  • Red Hat Enterprise Linux 3
  • Not for Red Hat Enterprise Linux 6, 7, 8 , please refer the NOTE in the resolution section.

Issue

  • How to enable core file dumps when an application crashes or segmentation faults (segfault)
  • How to configure core dumps in Red Hat Enterprise Linux
  • How to generate a core dump in Red Hat Enterprise Linux

Resolution

Note: There are a couple of ways to enable core file creation.

Preferred method

  1. Replace the above ulimit command in /etc/profile with the following (this will allow all users to produce core files of unlimited size):

    # ulimit -S -c unlimited > /dev/null 2>&1
    
  2. 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>
    
  3. The field < 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
    
  4. 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 generate a core, make sure that the application has the correct uid and that it does not use setuid to change uid when running.

    • RHEL 3, use the following command to enable the dumping of setuid applications:

          # echo 1 > /proc/sys/kernel/core_setuid_ok
      
    • Other RHEL version, use following sysctl settings. The core_pattern below is just an example.

      kernel.core_pattern=/var/tmp/core
      kernel.core_uses_pid=1
      fs.suid_dumpable=1
      

Alternate method

1, The following method has been provided by Red Hat, but is outside the scope of the posted Service Level Agreements and support procedures.

  1. Add the following call to the application source (in the C language):

        prctl(PR_SET_DUMPABLE, 1);
    

Notes

Root Cause

  • 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
    

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.

8 Comments

Hallo,

I think point 5 on this site differs to the second passage on this page "https://access.redhat.com/knowledge/solutions/4058".

I think point 5 is not correct for rhel 5, I think for rhel 5 the solution on the other page is the right one?

Regards,
Stefan

To test that your configuration is right

what signals are valid for this platform

kill -l 

BE CAREFUL

kill -6 <pid>

or

kill -SIGABRT <pid>

or

kill -ABRT <pid>

To it manually

gcore <pid>

i understand normal method , but i am bit more explanations on alternative method .

Suppose daemon is automatically stopping. Can I get coredump?

improvisioning is my service name How to get core dump? Can nay one help on this?

Is it just me, or are steps #1 and #3 in the Resolution confusingly conflicting? It says to modify the ulimit line in /etc/profile, but then also that you must comment out the line that you've already modified. My reading is that it is sufficient to just modify it as in step 1, but it could probably stand to be stated more clearly if that is the case. If anyone can confirm that's what is intended, I can edit.

Thanks

Where is the writeup on how to enable core dumps for RH7???

Helpful