Commit a24c1aab authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Mark rcu_cpu_kthread() accesses to ->rcu_cpu_has_work 



The rcu_data structure's ->rcu_cpu_has_work field can be modified by
any CPU attempting to wake up the rcuc kthread.  Therefore, this commit
marks accesses to this field from the rcu_cpu_kthread() function.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 9146eb25

kernel/rcu/tree.c

+2 −2
Original line number Diff line number Diff line
@@ -2481,12 +2481,12 @@ static void rcu_cpu_kthread(unsigned int cpu) 
		*statusp = RCU_KTHREAD_RUNNING;

		local_irq_disable();

		work = *workp;

		*workp = 0;

		WRITE_ONCE(*workp, 0);

		local_irq_enable();

		if (work)

			rcu_core();

		local_bh_enable();

		if (*workp == 0) {

		if (!READ_ONCE(*workp)) {

			trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));

			*statusp = RCU_KTHREAD_WAITING;

			return;