Re: md_raid: mdX_raid6 looping after sync_action "check" to "idle" transition

[Guoqing Jiang]

On 2/8/21 12:38, Donald Buczek wrote:
> > 5. maybe don't hold reconfig_mutex when try to unregister sync_thread, 
> > like this.
> >
> >          /* resync has finished, collect result */
> >          mddev_unlock(mddev);
> >          md_unregister_thread(&mddev->sync_thread);
> >          mddev_lock(mddev);
>
> As above: While we wait for the sync thread to terminate, wouldn't it be 
> a problem, if another user space operation takes the mutex?

I don't think other places can be blocked while hold mutex, otherwise 
these places can cause potential deadlock. Please try above two lines 
change. And perhaps others have better idea.

Thanks,
Guoqing