From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> The rcu_state structure's ncpus field is only to be modified by the CPU-hotplug CPU-online code path, which is single-threaded. This commit therefore enlists KCSAN's help in enforcing this restriction. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f13130a..4fd3e0f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3612,6 +3612,7 @@ void rcu_cpu_starting(unsigned int cpu) nbits = bitmap_weight(&oldmask, BITS_PER_LONG); /* Allow lockless access for expedited grace periods. */ smp_store_release(&rcu_state.ncpus, rcu_state.ncpus + nbits); /* ^^^ */ + ASSERT_EXCLUSIVE_WRITER(rcu_state.ncpus); rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */ rdp->rcu_onl_gp_seq = READ_ONCE(rcu_state.gp_seq); rdp->rcu_onl_gp_flags = READ_ONCE(rcu_state.gp_flags); -- 2.9.5
