Re: [PATCH] locking/osq_lock: fix a data race in osq_wait_next

From: Peter Zijlstra
Date: Wed Jan 29 2020 - 13:49:47 EST


On Tue, Jan 28, 2020 at 04:22:53PM -0800, Paul E. McKenney wrote:
> On Tue, Jan 28, 2020 at 05:56:55PM +0100, Peter Zijlstra wrote:
> > On Tue, Jan 28, 2020 at 12:46:26PM +0100, Marco Elver wrote:
> >
> > > > Marco, any thought on improving KCSAN for this to reduce the false
> > > > positives?
> > >
> > > Define 'false positive'.
> >
> > I'll use it where the code as written is correct while the tool
> > complains about it.
>
> I could be wrong, but I would guess that Marco is looking for something
> a little less subjective and a little more specific. ;-)

How is that either? If any valid translation by a compile results in
correct functionality, yet the tool complains, then surely we can speak
of a objective fact.