From 5e0018b3e39e9b44dbfb380b83026e55d2f65b91 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 13 Sep 2017 13:08:22 -0700 Subject: [PATCH] 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 Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2d7df5cc955b..9deb5a245b83 100644 --- 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;