On Thu, May 30, 2019 at 08:00:12AM -0700, Paul E. McKenney wrote: > The sync_exp_work_done() function uses smp_mb__before_atomic(), but > there is no obvious atomic in the ensuing code. The ordering is > absolutely required for grace periods to work correctly, so this > commit upgrades the smp_mb__before_atomic() to smp_mb(). >
Did this commit want a Fixes: line? Such that robots can find the right kernels to backport this to? > Reported-by: Andrea Parri <[email protected]> > Signed-off-by: Paul E. McKenney <[email protected]> > --- > kernel/rcu/tree_exp.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h > index 9c990df880d1..d969650a72c6 100644 > --- a/kernel/rcu/tree_exp.h > +++ b/kernel/rcu/tree_exp.h > @@ -259,8 +259,7 @@ static bool sync_exp_work_done(unsigned long s) > { > if (rcu_exp_gp_seq_done(s)) { > trace_rcu_exp_grace_period(rcu_state.name, s, TPS("done")); > - /* Ensure test happens before caller kfree(). */ > - smp_mb__before_atomic(); /* ^^^ */ > + smp_mb(); /* Ensure test happens before caller kfree(). */ > return true; > } > return false; > -- > 2.17.1 >
