Core/Crash Dumps and Debugging? How to make it (not) work?

[TwoFistedJustice]

Kubuntu 22.04

I'm fiddling about with basic C programming to learn Linux system calls. I am using gcc to compile. I am trying to deliberately generate some core/crash dumps in order to learn how to debug with them. Problem is I can't actually generate core dumps. I've tried ulimit -c unlimited, I've enabled core dumps in apparmor, installed and configured kdump according to the docs.


And I get absolutely NOTHING. Not even so much as an error message.

How do I make Kubuntu generate core dumps and then find them afterwards?


Should I use some other distro for this?

[jlittle]

Ubuntu these days sets up apport to handle core dumps. (see /proc/sys/kernel/core_pattern). In my 23.04 they've gone to /var/lib/apport/coredump, though I don't know what magic is required to persuade apport to actually write things there.

Simplest might be to edit /proc/sys/kernel/core_pattern to have a single word, say "my_core". Again, I'm not sure what's required, perhaps some group membership.

Installing systemd-coredump might be a more modern approach, but I haven't tried it.

[Snowhog]

Maybe https://askubuntu.com/questions/9664...109747#1109747 (see 31)

[TwoFistedJustice]

Seems like modern Debian robustly prevents core dumps. Neither Kubuntu nor Kali generate them (that I can see) no matter how many hacks I shove down their throats.

There might be something to Jlittle's suggestion of systemd-coredump.

I'm going to drop these two links from Suse here for later.

https://www.suse.com/support/kb/doc/?id=000015982


https://www.suse.com/support/kb/doc/?id=000018634

[TwoFistedJustice]

For future reference:

/etc/systemd/systemd.conf

try uncommenting:

#DumpCore=yes