Re: [PATCH] KEYS: dispatch key_gc_work to system_wq.

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Oct 26, 2026 at 06:57:22PM +0200, Jarkko Sakkinen wrote:
> > --- x/security/keys/gc.c
> > +++ y/security/keys/gc.c
> > @@ -270,9 +270,8 @@ contended:
> >  
> >  maybe_resched:
> >  	if (cursor) {
> > -		cond_resched();
> > -		spin_lock(&key_serial_lock);
> > -		goto continue_scanning;
> > +		schedule_work(&key_gc_work);
> > +		return;
> >  	}

I guess I'll to elaborate my fix and this proposal as you gave feedback
of neither.

What you wanted to respond to my patch other than nitpicking is probably
this sequence:

  key_garbage_collector()
    synchronize_rcu()
      synchronize_rcu_normal()
        wait_for_completion()
          schedule_timeout()
            schedule()

I should have put this to the commit message, and missed also this
detail.

So the way I saw this, which could be wrong, is that the workqueue
lockup would could happen less often as also other threads are scheduled
preemptively in unbounded queue outside critical sections.

What you are doing with early return is at least not right as it 
corrupts the state. So you should supplement that with something
that carries it.

Br, Jarkko