Re: [PATCH rcu 2/4] rcutorture: Fix rcu_torture_fwd_cb_cr() data race

2024-06-05 Thread Paul E. McKenney
On Wed, Jun 05, 2024 at 09:56:41AM +0200, Marco Elver wrote: > On Wed, 5 Jun 2024 at 00:36, Paul E. McKenney wrote: > > > > On powerpc systems, spinlock acquisition does not order prior stores > > against later loads. This means that this statement: > > > > rfcp->rfc_next = NULL; > > > >

Re: [PATCH rcu 2/4] rcutorture: Fix rcu_torture_fwd_cb_cr() data race

2024-06-05 Thread Marco Elver
On Wed, 5 Jun 2024 at 00:36, Paul E. McKenney wrote: > > On powerpc systems, spinlock acquisition does not order prior stores > against later loads. This means that this statement: > > rfcp->rfc_next = NULL; > > Can be reordered to follow this statement: > > WRITE_ONCE(*rfcpp, rfc

[PATCH rcu 2/4] rcutorture: Fix rcu_torture_fwd_cb_cr() data race

2024-06-04 Thread Paul E. McKenney
On powerpc systems, spinlock acquisition does not order prior stores against later loads. This means that this statement: rfcp->rfc_next = NULL; Can be reordered to follow this statement: WRITE_ONCE(*rfcpp, rfcp); Which is then a data race with rcu_torture_fwd_prog_cr(), specif