Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752200AbdIMUJd (ORCPT ); Wed, 13 Sep 2017 16:09:33 -0400 Received: from smtp2.provo.novell.com ([137.65.250.81]:36202 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028AbdIMUIf (ORCPT ); Wed, 13 Sep 2017 16:08:35 -0400 From: Davidlohr Bueso To: mingo@kernel.org, peterz@infradead.org, pbonzini@redhat.com Cc: npiggin@gmail.com, paulmck@linux.vnet.ibm.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH 5/7] kvm: Serialize wq active checks in kvm_vcpu_wake_up() Date: Wed, 13 Sep 2017 13:08:22 -0700 Message-Id: <20170913200824.28067-6-dave@stgolabs.net> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170913200824.28067-1-dave@stgolabs.net> References: <20170913200824.28067-1-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 729 Lines: 25 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 --- 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 6ed1c2021198..c41d903c5783 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2186,7 +2186,7 @@ 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; -- 2.12.0