﻿id	summary	reporter	owner	description	type	status	component	version	resolution	keywords	cc	guest	host
18632	Guru meditation with SW virtualization and serial port (VirtualBox 5->6 regression) => fixed in SVN/next maintenance	Ambroz Bizjak		"With VirtualBox 6.0.6, when SW virtualization is used, a serial port is enabled and the guest runs Linux, guru meditation results during guest kernel startup. This is a regression compared to 5.2.28.

To reproduce:
- Create a new VM with type ""Linux / Other Linux (32-bit)"".
- Attach CD image: [https://gensho.ftp.acc.umu.se/debian-cd/current/i386/iso-cd/debian-9.9.0-i386-netinst.iso Debian 32-bit netinst ISO]. (probably any 32-bit Linux will do)
- Disable hardware virtualization (Enable VT-x/AMD-V = off).
- Enable serial port 1 (COM1, can be Disconnected).
- Run this command to prevent a kernel panic that would otherwise occur: VBoxManage modifyvm VM_NAME --cpu-profile ""Intel Xeon X5482 3.20GHz"".
- Start the VM.
- Result: Guru Meditation during guest kernel startup.

{{{
00:00:15.463906 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
00:00:15.463907 !!
00:00:15.463908 !!         VCPU0: Guru Meditation -2403 (VERR_TRPM_DONT_PANIC)
00:00:15.463915 !!
00:00:15.463918 !! TRAP=0e ERRCD=0000000000000010 CR2=00000000a0622f60 EIP=a0622f60 Type=0 cbInstr=ff
00:00:15.463926 !! EIP is not in any code known to VMM!
00:00:15.463931 !!
00:00:15.463932 !!
00:00:15.463932 !!
}}}

This was originally experienced in automated tests for the NixOS distribution, a fragment of the error from there can be found in [https://github.com/NixOS/nixpkgs/pull/60943#issuecomment-489450069 this comment]. The guru meditation happens just as the kernel initializes the serial port (this is not clear with this debian iso).

This could be the same bug as experienced in [https://forums.virtualbox.org/viewtopic.php?f=6&t=91974 this forum post]. Here VBox crashes with the same error while running a Windows XP guest, just as a program tries to open a serial port, and it was also with SW-based virtualization."	defect	closed	uart	VirtualBox 6.0.6	fixed			Linux	all
