[5.1 regression] Operations involving network adapters freeze the guest

[cremor]

Since VirtualBox 5.1 was released I tried to upgrade from 5.0 multiple times. But every time I try, I get guest freezes for operations that involve network adapters. I've never had this problem with any version before, including all 5.0 versions. Downgrading to 5.0 (e.g. 5.0.26) fixes the problem.

I currently know of two ways to reproduce the freeze. It isn't reproducable 100% of the time, but about 75% - enough to be very annoying in regular use.

1. Trying to connect to a VPN network. For that I use the software "FortiClient SSLVPN". The freeze happens when I start the software, so before I even try to connect.
2. Opening the "network adapters" window in the Windows system settings.

So it seems like if something is done with my virtual network adapters, the freeze happens. Since opening the system settings window or a VPN client window is enough, it seems like it is related to something like a status query on the adapters.

When the guest is frozen, the host task manager shows about 30% CPU usage (just above one core on my 4 core machine) for the VirtualBox process all the time. The guest is completely unresponsive, I can only do a hard shutdown.

I've attached the log files and minidump from a freeze.

My environment:

VirtualBox 5.1.8 (but the freeze was already in 5.1) Extension pack and guest additions installed and updated to same version as VirtualBox.

Host: Windows 10 version 1511 Enterprise x64 with all updates Intel Core i5-6600, 16 GB RAM Network adapter: Intel I219-V

Guest: Windows 10 version 1511 Enterprise x64 with all updates 4 cores and 6 GB RAM assigned ICH9 chipset, IO-APIC, PAE/NX, Hyper-V, VT-x and Nested Paging enabled Virtual network adapter: Intel PRO/1000 MT Desktop using bridge configuration

[cremor]

The freeze is not related to bridged networking. I just reproduced it with NAT networking by just booting the guest, waiting a few seconds and then opening the Windows network configuration window. I'll attach those log files and the minidump too.

[cremor]

I don't know when this was fixed, but it was a long time ago. So this ticket can be closed.

[paulson]

Closing as per submitter's advice.