Win 7 x64 Guest on Ubuntu 16.04 Host Freeze after ~4 Hours

[John Mackoy]

Have had a persistent problem for some time now (unsure when it started) whereby my Windows 7 x64 guest will completely lock up and is unresponsive. VirtualBox console and other running non-Windows VMs do not seem to be affected. The VirtualBox interface is still active and I can manipulate settings via the menu options in the GUI, but the guest OS GUI is frozen at the point it stopped working.

Saving State, then Restoring doesn't affect the outcome - only way to recover is to power off the guest VM and start it up again.

Reported this issue over in the forum (​https://forums.virtualbox.org/viewtopic.php?f=7&t=82819) and was advised that this may be a rarely reproducible issue involving the NAT network subsystem and that logging a bugtrac ticket would be the best way to address this issue.

This appears to be the point at which the guest crashes (from Vbox.log):

00:26:21.080234 NAT: resolv.conf: nameserver 192.168.56.50
00:26:21.080254 NAT: resolv.conf: nameserver 127.0.1.1
00:26:21.080262 NAT: Adding domain name laptop
00:26:21.080264 NAT: DNS#0: 192.168.56.50
00:26:21.080266 NAT: DNS#1: 127.0.1.1
00:26:21.080269 NAT: DHCP offered IP address 10.0.2.15
00:26:22.688094 NAT: dnsproxy: timeout: req 00007f56d4071640 dnsgen 2 != 3 on socket 50 (udp) exp. in -427 state=SS_ISFCONNECTED f_(addr:port)=10.0.2.3:53 l_(addr:port)=10.0.2.15:50425 name=0.0.0.0:54045
03:01:30.079058 NAT: Can't allocate mbuf
03:01:38.957814 NAT: Link up
03:01:44.952776 NAT: Link up
03:01:50.966947 NAT: Link up
03:01:56.962828 NAT: Link up
03:02:02.966836 NAT: Link up
03:02:23.001524 NAT: Link up
03:02:29.001906 NAT: Link up
03:02:32.603387 VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received 4 seconds ago

Full vbox.log file attached. Core dump is available, but may contain sensitive data so I'd prefer not to attach to this ticket. Have an email out to Frank Mehnert, but would gladly take instruction from elsewhere on how to get this to interested parties, securely.

[John Mackoy]

VBox.log from affected guest

[Frank Mehnert]

John, I would like to have a look at the core dump but the chances are low that the core dump will really show the reason because the log file shows that the heartbeat timer signals the guest does not respond. Which looks more like a guest problem.

Does this also happen if you disable 3D support for this guest in the VM settings?

Unfortunately I cannot provide you a server for upload. Please either use some anonymous server and tell me the URL or split the mail into chunks of ~7MB (you said your file is ~20MB) and mail me these files.