Hi,

In schedule.c, schedule() and sched_adjust() call trace functions during
acquiring lock of schedule_lock in each cpu's schedule_data. When trace
buffers are enabled, the trace function (__trace_var()) may call
vcpu_wake() by calling send_guest_global_virq(). In the case, a deadlock
occurs when acquiring lock of schedule_lock.

Attached patch fixes this problem.

Signed-off-by: Naoki Nishiguchi <nisiguti@jp.fujitsu.com>

Regards,
Naoki Nishiguchi