FYI, we noticed the following commit:

commit: f2cb13609d5397cdd747f3ed6fb651233851717d ("sched/topology: Split out scheduler topology code from core.c into topology.c")
https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core

in testcase: boot

on test machine: qemu-system-i386 -enable-kvm -m 360M

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+---------------------------+------------+------------+
|                           | 004172bdad | f2cb13609d |
+---------------------------+------------+------------+
| boot_successes            | 8          | 4          |
| boot_failures             | 0          | 4          |
| BUG:workqueue_lockup-pool | 0          | 4          |
+---------------------------+------------+------------+



[  301.281899] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 46s!
[  301.281899] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 46s!
[  301.303924] Showing busy workqueues and worker pools:
[  301.303924] Showing busy workqueues and worker pools:
[  301.318191] workqueue events: flags=0x0
[  301.318191] workqueue events: flags=0x0
[  301.329514]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256
[  301.329514]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256
[  301.338803]     in-flight: 19:rht_deferred_worker
[  301.338803]     in-flight: 19:rht_deferred_worker
[  301.338803]     pending: tsc_refine_calibration_work, rht_deferred_worker, free_work
[  301.338803]     pending: tsc_refine_calibration_work, rht_deferred_worker, free_work
[  301.386552] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=46s workers=2 idle: 3
[  301.386552] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=46s workers=2 idle: 3


To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong