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| author | Paul E. McKenney <paulmck@kernel.org> | 2020-01-03 12:12:06 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-02-20 15:58:22 -0800 |
| commit | b0c18c87730a4de6da0303fa99aea43e814233f9 (patch) | |
| tree | 31f1ab63c9331736ccd4b7aa54bfb2db389c94f4 | |
| parent | 7672d647ddae37d2ea267159950bcc311e962434 (diff) | |
rcu: Add WRITE_ONCE to rcu_node ->exp_seq_rq store
The rcu_node structure's ->exp_seq_rq field is read locklessly, so
this commit adds the WRITE_ONCE() to a load in order to provide proper
documentation and READ_ONCE()/WRITE_ONCE() pairing.
This data race was reported by KCSAN. Not appropriate for backporting
due to failure being unlikely.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | kernel/rcu/tree_exp.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index d7e04849c7ab..85b009e05637 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -314,7 +314,7 @@ static bool exp_funnel_lock(unsigned long s) sync_exp_work_done(s)); return true; } - rnp->exp_seq_rq = s; /* Followers can wait on us. */ + WRITE_ONCE(rnp->exp_seq_rq, s); /* Followers can wait on us. */ spin_unlock(&rnp->exp_lock); trace_rcu_exp_funnel_lock(rcu_state.name, rnp->level, rnp->grplo, rnp->grphi, TPS("nxtlvl")); |