I hit an issue on xen dom0 when working with most recent mainline linux. I am
posting this to share the symptom and commit fixing the issue, so that people
would be able to search via google in the future when hit the same issue.
The issue is already fixed by Michal Hocko <[hidden email]> and the patch set
is queued in linux-next.
When I boot either HVM or PV guest, xenconsoled is blocked in Running state.
The backtrace obtained via 'echo "l" > /proc/sysrq-trigger' is as below: