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Subject[PATCH tip/core/rcu 6/9] rcu: Upgrade sync_exp_work_done() to smp_mb()
Date
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().

Reported-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
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
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