Arch Linux

paulm

Member

Registered: 2020-01-02

Posts: 4

Mate-session limiting core dump size?

I've been trying to figure out why the shell in my mate-terminal is not allowing an unlimited core dump file size:

paulm@cmstorm 15:07:~$ ulimit -a
core file size          (blocks, -c) 250000000
...
paulm@cmstorm 15:07:~$ ulimit -c unlimited
bash: ulimit: core file size: cannot modify limit: Operation not permitted

It appears there's a 250MB limit being set somewhere, but I can't figure out where. I've checked every configuration file I know of (/etc/systemd/user.conf, /etc/security/limits.conf, ~/.bashrc and friends) for any limit set but there isn't. The kernel and systemd default should be unlimited.

Looking at the process tree it appears mate-session is where the limit gets applied first:

root         699  1.1  1.5 1051852 517780 tty7   Ss+   2019 635:29  \_ /usr/lib/Xorg :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
root         838  0.0  0.0 160524  6556 ?        Sl    2019   0:00  \_ lightdm --session-child 12 19
paulm        859  0.0  0.0 316700 29948 ?        Ssl   2019   6:46      \_ mate-session
paulm        901  0.0  0.0 1358684 32184 ?       Sl    2019   6:37          \_ /usr/lib/mate-settings-daemon/mate-settings-daemon
paulm        909  0.0  0.1 350572 48872 ?        Sl    2019   7:34          \_ marco
paulm        925  0.0  0.2 1129044 88568 ?       Sl    2019   5:24          \_ mate-panel

# Xorg
root@cmstorm:~# grep core /proc/699/limits
Max core file size        unlimited            unlimited            bytes     
# lightdm
root@cmstorm:~# grep core /proc/838/limits
Max core file size        unlimited            unlimited            bytes     
# mate-session
root@cmstorm:~# grep core /proc/859/limits
Max core file size        256000000000         256000000000         bytes     

The difference between limits for lightdm and mate-session is only the core dump size:

root@cmstorm:~# cat /proc/838/limits > lightdm.txt
root@cmstorm:~# cat /proc/859/limits > mate-session.txt
root@cmstorm:~# diff -ur lightdm.txt mate-session.txt 
--- lightdm.txt	2020-01-02 15:13:31.098001661 +0100
+++ mate-session.txt	2020-01-02 15:13:35.687911282 +0100
@@ -3,7 +3,7 @@
 Max file size             unlimited            unlimited            bytes     
 Max data size             unlimited            unlimited            bytes     
 Max stack size            8388608              unlimited            bytes     
-Max core file size        unlimited            unlimited            bytes     
+Max core file size        256000000000         256000000000         bytes     
 Max resident set          unlimited            unlimited            bytes     
 Max processes             128272               128272               processes 
 Max open files            1024                 524288               files     

I guess technically lightdm could be setting the limit as well in the forked child when starting mate-session, so that would be the other thing to check. But does anyone have any idea what is going on here? Is there a MATE configuration setting I'm not aware of? I've checked on my other Arch systems, which do not show this behaviour.