linux limits.conf not working?

Question

I configured /etc/security/limits.conf like this.

user1               soft    core            0
user1               hard    core            0

Then, I rebooted the system and logged in as root then I did this.

su user1
ulimit -c unlimited

then I executed a buggy application to generate core file. since I set the core limit to zero from limits.conf, I expected the core will not be generated but, that was not the result, the core was normally generated. what's wrong??

some advice would be appreciated.

Answer 1

limits.conf is read by pam_limits.so, so you need to check that this module is enabled in /etc/pam.d/su. On my system, this was commented out by default:

# Sets up user limits, please uncomment and read /etc/security/limits.conf
# to enable this functionality.
# (Replaces the use of /etc/limits in old login)
# session    required   pam_limits.so

Once uncommented, the module will start working immediately. If you still have problems, check your auth log (maybe /var/log/auth.log), which is where limits-related errors will be written.