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: ​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 ​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 ​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.

[Ambroz Bizjak]

Machine log

[aeichner]

Thanks for the report and the detailed steps provided! This issue will be fixed in the next maintenance release.