Re: rcu_read_lock lost its compiler barrier

From: Paul E. McKenney
Date: Thu Jun 06 2019 - 02:09:27 EST

On Thu, Jun 06, 2019 at 12:51:09PM +0800, Herbert Xu wrote:
> On Tue, Jun 04, 2019 at 10:44:18AM -0400, Alan Stern wrote:
> >
> > Currently the LKMM says the test is allowed and there is a data race,
> > but this answer clearly is wrong since it would violate the RCU
> > guarantee.
> Thank you! This is what I tried to say all along in this thread
> but you expressed it in a much better way :)

In case you were wondering, the reason that I was giving you such
a hard time was that from what I could see, you were pushing for no
{READ,WRITE}_ONCE() at all. ;-)

Thanx, Paul