Commit 343640cb authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load 



The rcu_request_urgent_qs_task() function does a cross-CPU store
to ->rcu_urgent_qs, so this commit therefore marks the load in
__rcu_irq_enter_check_tick() with READ_ONCE().

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
parent ed2b9e1b

kernel/rcu/tree.c

+1 −1
Original line number Diff line number Diff line
@@ -632,7 +632,7 @@ void __rcu_irq_enter_check_tick(void) 
	// prevents self-deadlock.  So we can safely recheck under the lock.

	// Note that the nohz_full state currently cannot change.

	raw_spin_lock_rcu_node(rdp->mynode);

	if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {

	if (READ_ONCE(rdp->rcu_urgent_qs) && !rdp->rcu_forced_tick) {

		// A nohz_full CPU is in the kernel and RCU needs a

		// quiescent state.  Turn on the tick!

		WRITE_ONCE(rdp->rcu_forced_tick, true);