diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2020-01-03 15:17:12 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-02-20 15:58:22 -0800 |
| commit | 2906d2154cd6ad6e4452cc25315d3cea7bb7f2d7 (patch) | |
| tree | 4cbf03a8df843b417949fd9fe4c3b7018f0fb9ef /kernel | |
| parent | 0937d045732b5dd5e5df1fb6355d5f4e01f3c4d7 (diff) | |
rcu: Add WRITE_ONCE() to rcu_state ->gp_req_activity
The rcu_state structure's ->gp_req_activity field is read locklessly,
so this commit adds the WRITE_ONCE() to an update 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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 236692d7762f..944390981aed 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1200,7 +1200,7 @@ static bool rcu_start_this_gp(struct rcu_node *rnp_start, struct rcu_data *rdp, } trace_rcu_this_gp(rnp, rdp, gp_seq_req, TPS("Startedroot")); WRITE_ONCE(rcu_state.gp_flags, rcu_state.gp_flags | RCU_GP_FLAG_INIT); - rcu_state.gp_req_activity = jiffies; + WRITE_ONCE(rcu_state.gp_req_activity, jiffies); if (!rcu_state.gp_kthread) { trace_rcu_this_gp(rnp, rdp, gp_seq_req, TPS("NoGPkthread")); goto unlock_out; @@ -1775,7 +1775,7 @@ static void rcu_gp_cleanup(void) rcu_segcblist_is_offloaded(&rdp->cblist); if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) { WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT); - rcu_state.gp_req_activity = jiffies; + WRITE_ONCE(rcu_state.gp_req_activity, jiffies); trace_rcu_grace_period(rcu_state.name, READ_ONCE(rcu_state.gp_seq), TPS("newreq")); |