diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-03-07 07:21:23 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-03-16 14:06:08 -0700 |
| commit | 71c66a41497bb942335f60dde9539d5acdcbfe1d (patch) | |
| tree | 871cf889bcb7c6f679aad80bad8192bdf1d7eb3f /kernel | |
| parent | 82139b509224542131086129a76f8e60a21d4932 (diff) | |
rcu: Add smp_mb__after_atomic() to sync_exp_work_done()
The sync_exp_work_done() function needs to fully order the counter-check
operation against anything happening after the corresponding grace period.
This is a theoretical bug, as all current architectures either provide
full ordering for atomic operation on the one hand or implement,
however, a little future-proofing is a good thing. This commit
therefore adds smp_mb__after_atomic() after the atomic_long_inc()
in sync_exp_work_done().
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree_exp.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 027e123d93c7..652071abd9b4 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -247,6 +247,7 @@ static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat, /* Ensure test happens before caller kfree(). */ smp_mb__before_atomic(); /* ^^^ */ atomic_long_inc(stat); + smp_mb__after_atomic(); /* ^^^ */ return true; } return false; |