Re: BUG: HANG_DETECT waiting for migration_cpu_stop() complete

[Tejun Heo]

Hello,

(cc'ing Waiman in case he has a better idea)

On Mon, Sep 05, 2022 at 04:22:29PM +0800, Jing-Ting Wu wrote:
> https://lore.kernel.org/lkml/YvrWaml3F+x9Dk+T@xxxxxxxxxxxxxxx/ is for
> fix cgroup_threadgroup_rwsem <-> cpus_read_lock() deadlock.
> But this issue is cgroup_threadgroup_rwsem <-> cpuset_rwsem deadlock.

If I'm understanding what you're writing correctly, this isn't a deadlock.
The cpuset_hotplug_workfn simply isn't being woken up while holding
cpuset_rwsem and others are just waiting for that lock to be released.

Thanks.

-- 
tejun