Failure to unplug VIF

["Tu Dinh" <ngoc-tu.dinh@xxxxxxxxxx>]

Hello all,

I'm running into a difficult problem where unplugging a VIF causes it to 
get stuck inside the guest.

dead13.log happened when plugging a VIF immediately followed by 
unplugging it as quickly as possible. There's a specific timing needed 
to hit the bug. On my machine I managed to consistently reproduce the 
problem by mashing the VIF unplug button in Xen Orchestra.

After the unplug, both the backend xenstore path 
(/local/domain/0/backend/vif/domid) and frontend path 
(/local/domain/domid/device/vif) disappear successfully, but no further 
reconfiguration will succeed. The virtual NIC also still shows up inside 
the guest, but is stuck disabled and cannot be enabled. The transmitter 
watchdog is also still running and printing debug warnings every once in 
a while.

It looks like after IRP_MN_QUERY_REMOVE_DEVICE is issued, 
FrontendDisable never actually gets called and so the teardown gets stuck.

For reference, nodead13.log is when there's sufficient time to unplug, 
and there's no problems.

Looking for some opinion on this problem.

Thanks in advance,

--
Ngoc Tu Dinh | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech

Attachment: dead13.log
Description: Text document

Attachment: nodead13.log
Description: Text document