kvm: Serialize wq active checks in kvm_vcpu_wake_up()

This is a generic call and can be suceptible to races in reading the wq task_list while another task is adding itself to the list. Add a full barrier by using the swq_has_sleeper() helper. Signed-off-by: Davidlohr Bueso <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]>
modi0012 · Sep 15, 2017 · 5e0018b · 5e0018b
1 parent a0cff57
commit 5e0018b
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
@@ -2187,7 +2187,7 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 	struct swait_queue_head *wqp;
 
 	wqp = kvm_arch_vcpu_wq(vcpu);
-	if (swait_active(wqp)) {
+	if (swq_has_sleeper(wqp)) {
 		swake_up(wqp);
 		++vcpu->stat.halt_wakeup;
 		return true;