Changes between Version 43 and Version 44 of Core_dump

Timestamp:

Mar 21, 2013 2:12:29 PM (12 years ago)

Author:

Michael Thayer

Comment:

Core dumps on Ubuntu need suid_dumpable to be enabled too.

Core_dump

@@ -5 +5 @@
 = How to create a core dump on Linux =
 
-The procedure for creating a core dump is similar on most Linux systems, but on Ubuntu it is slightly different due to the Ubuntu crash reporting tool (Apport).
+!VirtualBox is (as of version 2.0.0) a system application which can be started from a user account without special privileges - a so-called "setuid" application.  As core dumps are usually not allowed for these sensitive applications you have to explicitly allow them after starting your computer but before the crash which you want a core dump from.  This can be done by typing the following command at the command line (your user account must be allowed to use the "sudo" command):
+{{{
+$ echo -n 1 | sudo tee /proc/sys/fs/suid_dumpable
+}}}
+The procedure for actually creating a core dump is similar on most Linux systems, but on Ubuntu it is slightly different due to the Ubuntu crash reporting tool (Apport).
 
 == To create a core dump on an Ubuntu system ==
@@ -17 +21 @@
 
 == To create a core dump on non-Ubuntu systems ==
+
 start !VirtualBox from a command line (e.g. xterm):
 {{{
 $ ulimit -c unlimited
-$ sudo su
-# echo -n 1 > /proc/sys/kernel/core_uses_pid
-# echo -n 1 > /proc/sys/fs/suid_dumpable
-# exit
+$ echo -n 1 | sudo tee /proc/sys/fs/suid_dumpable
 $ VirtualBox
 }}}
-or better start the VM directly:
+or if possible start the virtual machine directly:
 {{{
 $ ulimit -c unlimited
-$ sudo su
-# echo -n 1 > /proc/sys/kernel/core_uses_pid
-# echo -n 1 > /proc/sys/fs/suid_dumpable
-# exit
+$ echo -n 1 | sudo tee /proc/sys/kernel/core_uses_pid
 $ /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`, that is, with permissions to do things that "normal" applications cannot. This is the reason for the
-{{{
-$ sudo su
-$ echo -n 1 > /proc/sys/fs/suid_dumpable
-$ exit
-}}}
-before starting the VM/GUI (note that `sudo echo` will not do what we want here).
 
 When !VirtualBox or one of its processes 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_ oracle _dot_ com if the compressed file is smaller than 5MB. Upload it to ftp.oracle.com:/appsdev/incoming and contact me directly otherwise to tell me the file name of the uploaded core dump.