Where do I find the core dump in ubuntu 16.04LTS?

Solution 1:

In Ubuntu the core dumps are handled by Apport and can be located in /var/crash/. But it is disabled by default in stable releases.

To enable Apport, run: sudo systemctl enable apport.service or sudo service apport start.

To disable, run: sudo systemctl disable apport.service or sudo service apport stop in order to back to regular core dumping method. See: How do I enable or disable Apport?.

To disable permanently, edit /etc/apport/crashdb.conf file and comment the following line:

'problem_types': ['Bug', 'Package'],

by adding a hash symbol (#) in the beginning of the line.

To disable crash reporting (back to normal), remove the hash symbol (the same as it was).

You can also check core_pattern, how core dumps are handled by the kernel:

$ cat /proc/sys/kernel/core_pattern
|/usr/share/apport/apport %p %s %c

So even core files are disabled by ulimit, apport will still capture the crash.

See also:

• How to generate a core dump in Linux?
• Core dumped, but core file is not in the current directory?
• for macOS, see: How to generate core dumps in Mac OS X?

Solution 2:

For those googlin': ( in my case -- Ubuntu 16.04 and 18.04 and a custom app ) /var/crash was still empty, so a quick way to handle core creation ( provided that you are e.g. using a relevant ulimit builtin setting ) was

sudo sysctl -w kernel.core_pattern=core.%u.%p.%t # to enable core generation

and

systemctl restart apport # to restore default apport settings
# which, by the way, were "|/usr/share/apport/apport %p %s %c %d %P" (without quotes)

• https://utcc.utoronto.ca/~cks/space/blog/linux/CoreDumpsOnServers
• http://man7.org/linux/man-pages/man5/core.5.html

Solution 3:

All the above did not worked for me... I looked at /var/log/apport.log:

cat /var/log/apport.log 

and I saw the file name:

ERROR: apport (pid 3426) Mon Nov  8 14:34:07 2021: writing core dump to core._home_guest_a_out.1000.4 ... 

and then I search throughout all the system

sudo find . -name "core._home_guest_a_out.1000.4..."

I found the core dump in /var/lib/apport/coredump/