[BUG REPORT] Triggering a panic in an x86 virtual machine does not wait

[Baokun Li]

When I manually trigger panic in a qume x86 VM with

       `echo c > /proc/sysrq-trigger`,

 I find that the VM will probably reboot directly, but the 
PANIC_TIMEOUT is 0.
This prevents us from exporting the vmcore via panic, and even if we succeed
in panic exporting the vmcore, the processes in the vmcore are mostly
stop_this_cpu(). By dichotomizing we found the patch that introduced the
behavior change

   45e34c8af58f ("x86/smp: Put CPUs into INIT on shutdown if possible"),

can anyone help to see what is happening?

Thanks!
--
With Best Regards,
Baokun Li
.