panic in do_sync_core in linux 5.13.12+ with Hyper-V on host

Discussions about using Linux guests in VirtualBox.
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940607
Posts: 57
Joined: 24. Sep 2012, 10:32
Primary OS: MS Windows 10
VBox Version: OSE other
Guest OSses: Archlinux
Location: Russia

panic in do_sync_core in linux 5.13.12+ with Hyper-V on host

Post by 940607 »

Hi. Occasionally I need to run Docker, WSL, and a VirtualBox Linux guest with 4 virtual CPUs on Windows 10 pro. For that reason I have the Windows component "Windows Hypervisor Platform".
Linux Kernels 5.13.10 and older worked stably, maybe 25% slower than with direct hardware Virtualization. However, after upgrading my VBox Guest VM to linux 5.14.9 it's having kernel Oops in do_sync_core quite regularly. Either during boot or shortly after. Sometimes the stack is printed on screen, but most often it just freezes with even the caret not blinking. In this case only one line is printed to VBox.log:

Code: Select all

00:00:58.129967 VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received 4 seconds ago
Sometimes there's EEPROM checksum error and I get no ethernet.

With the help of "downgrade" utility I figured out that 5.13.10 was the last good package and 5.13.12 and later were bad.

I even created a minimal VM for my colleagues to compare the setups: https://drive.google.com/file/d/1KD7ixa ... sp=sharing
After boot it automatically starts to build a package from AUR (the one I was building the first time I encountered the bug). This is how I was able to track it to "Windows Hypervisor Platform". Uninstalling it makes the guest work stably, but that's not an option.

Reducing the number of Guest CPUs from 4 to 1 makes the panic go away.

Can you try to reproduce the issue with the .ova above and back me up when I report this to kernel.org? Windows Hypervisor Platform has to be installed. Not sure what's the needed hardware.

Currently installed package on guest: linux 5.14.9
Host VirtualBox 6.1.26
Host Windows 10 Professional 64-bit (Build 19043)
video https://drive.google.com/file/d/1I6y0XK ... sp=sharing
VBoxLogs.zip, cpuz-report.zip, and console.zip with Oops details are attached
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cpuz-report.zip
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console.zip
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scottgus1
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Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: panic in do_sync_core in linux 5.13.12+ with Hyper-V on host

Post by scottgus1 »

I don't have the correct hardware to run this test, but I have a possible "frame challenge":

The effort to get Virtualbox to run under Hyper-V is an ongoing process and it has been off-and-on depending on many factors, including the OS being run in the VM. Maybe the new OS requirements & usage is upending the present Virtualbox/Hyper-V dalliance. A post on the Bugtracker with logs etc might help the devs see what's up.

Meanwhile the usual forum advice is to disable Hyper-V if running Virtualbox under Hyper-V fails. If Hyper-V is required for other usages, then use Hyper-V for your VMs too.
fth0
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Posts: 5668
Joined: 14. Feb 2019, 03:06
Primary OS: Mac OS X other
VBox Version: PUEL
Guest OSses: Linux, Windows 10, ...
Location: Germany

Re: panic in do_sync_core in linux 5.13.12+ with Hyper-V on host

Post by fth0 »

Before creating a ticket in the Bugtracker, you should probably try a VirtualBox test build, because Linux kernel 5.14 is only supported by VirtualBox test builds 6.1.27r146191 and newer.
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