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How to create a core dump on Linux ¶

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
$ sudo su
# echo -n 1 > /proc/sys/fs/suid_dumpable
# exit
$ VirtualBox

or better start the VM directly:

$ ulimit -c unlimited
$ sudo su
# echo -n 1 > /proc/sys/fs/suid_dumpable
# exit
$ /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 su
$ echo -n 1 > /proc/sys/fs/suid_dumpable
$ exit

before starting the VM/GUI (note that sudo echo will sometimes not work).

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.

How to create dumps on Mac OS X ¶

To create a core dump on Mac OS X, start VirtualBox from a command line:

$ ulimit -c unlimited
$ VirtualBox

or better start the VM directly:

$ ulimit -c unlimited
$ /Applications/VirtualBox.app/Contents/MacOS/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.

The core files can be found in the /cores folder.

How to create dumps on OpenSolaris ¶

To get core on OpenSolaris? host create coreadm.conf file

# cat /etc/coreadm.conf 
COREADM_GLOB_PATTERN=/tmp/cores/core.%f.%p
COREADM_GLOB_CONTENT=all
COREADM_INIT_PATTERN=%f.%p
COREADM_INIT_CONTENT=all
COREADM_GLOB_ENABLED=yes
COREADM_PROC_ENABLED=yes
COREADM_GLOB_SETID_ENABLED=yes
COREADM_PROC_SETID_ENABLED=yes
COREADM_GLOB_LOG_ENABLED=yes

then enforce coreadm(1) to read configuration from file

# coreadm -U
# pfexec svcs | grep coreadm
online         20:40:11 svc:/system/coreadm:default
# pfexec svcadm restart coreadm
# pfexec svcs | grep coreadm
online          5:30:22 svc:/system/coreadm:default
# ulimit -c unlimited

After mentioned above manipulations core files will appear in /var/cores folder

Forcing VirtualBox to terminate with a core dump ¶

Sometimes it is required to force a VirtualBox process to terminate, for example, a VM hangs for some unknown reason. On Linux, this can be done as follows:

$ 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

On Mac OS X:

$ ulimit -c unlimited
$ /Applications/VirtualBox.app/Contents/MacOS/VirtualBox -startvm VM_NAME &
$ ps aux|grep VirtualBox
... 7145 ... VirtualBox ...
$ kill -4 7145

On OpenSolaris?:

# ulimit -c unlimited
# /opt/VirtualBox/amd64/bin/VirtualBox -startvm VM_NAME &
# ps aux|grep VirtualBox
... 7145 ... VirtualBox ...
# kill -4 7145

You can find result core file according location specified in coreadm

# coreadm

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

How to minidumps on Windows

[linuxkernelnewbies] How to create dumps