How to create a core dump

A core dump is very helpful for helping us tracking down crashes of VirtualBox. To create a core dump, start VirtualBox from a command line (e.g. xterm):

$ ulimit -c unlimited
$ VirtualBox

or better start the VM directly:

$ ulimit -c unlimited
$ /usr/lib/virtualbox/VirtualBox -startvm VM_NAME

Ensure that no startup script (~/.bashrc, ~/.bash_profile, ~/.profile) contains an instruction like ulimit -c 0 as the limit cannot be increased once it was set to zero.

Starting with version 2.0.0, the VirtualBox processes are started suid root. Therefore do

$ sudo echo -n 1 > /proc/sys/fs/suid_dumpable

before starting the VM/GUI.

When VirtualBox crashes, a file core.<pid> is created in the current directory. Be aware that core dumps can be very huge. Please compress the file before submitting it to a bug report. Or better don't attach the file to a report. Note that this core dump can contain a memory dump of your guest which can include sensitive information. Send it to frank _dot_ mehnert at sun _dot_ com if the compressed file is smaller than 5MB. Contact me directly otherwise.

Forcing VirtualBox to terminate with core dump

Sometimes it is required to force a VirtualBox process to terminate, for example, a VM hangs for some unknown reason. This can be done like this (I assume that the VM was started from the GUI):

$ ulimit -c unlimited
$ sudo echo -n 1 > /proc/sys/fs/suid_dumpable
$ /usr/lib/virtualbox/VirtualBox -startvm VM_NAME &
$ pidof VirtualBox
7145
$ kill -4 7145

Passing the signal number 4 (SIGKILL) is essential! The same applies to the alternative frontends VBoxHeadless and VBoxSDL.