Description of problem:
when I install virtualbox guest additonal tools,
the computer automatically reboot，and it can't run successfully to login in.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Created attachment 431989 [details]
boot info about the error
Crash in an external binary module with hardly any information (e.g. vmcore). Also, it's not really clear that the reporter is using Xen at all. Closing for now, feel free to reopen and provide more information.
If you have an active subscription to RHEL5, using the standard support channels will help you restore the machine to a bootable state and gather this information (as well as guarantee a more timely response).