[Bug 120751] New: Host kernel freezes when I shutdown guest

bugzilla-daemon
2016-06-21T19:27:25Z

Bug ID: 120751
Summary: Host kernel freezes when I shutdown guest
Product: Virtualization
Version: unspecified
Kernel Version: 4.6.2
Hardware: x86-64
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: kvm
Assignee: virtualization_kvm@kernel-bugs.osdl.org
Reporter: mkletzan@redhat.com
Regression: No

I wasn't able to find the smallest case that would cause this, so I'll describe
the whole procedure how to reproduce this. I'll then try to narrow down the
cause. If there is some information I might gather anywhere, I'll be more than
happy to provide such information.

Reproducible: always

Steps:
1) I start a guest, switch to text console and login.
2) Then in the host I run:
a) 'virsh dompmsuspend $guest mem' which tells the guest's qemu-ga to
suspend to RAM.
b) I then run 'virsh dompmwakeup $guest' to wake it up. The guest console
misbehaves at this point (which is what I am trying to reproduce to solve
another bug).
3) So I connect using ssh and run 'shutdown -h now'.

Actual results:
At that point last fraction of the second of the music I was playing (whatever
remained in the buffer, I guess) starts repeating and the host stops
responding. Even Magic SysRq doesn't work. I have to manually force the host
off with a button and boot again.

Expected results:
Host keeps running.

I've first seen that in 4.6.2, I tried 4.6.0 and it happened as well. I'm not
sure whether this is related to Virtualization or graphics drivers or anything
else.