From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754371AbeDITkG (ORCPT ); Mon, 9 Apr 2018 15:40:06 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:53756 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754136AbeDITkE (ORCPT ); Mon, 9 Apr 2018 15:40:04 -0400 Date: Mon, 9 Apr 2018 22:40:02 +0300 From: "Michael S. Tsirkin" To: David Miller , netdev@vger.kernel.org, virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org, jasowang@redhat.com, kvm@vger.kernel.org, mst@redhat.com, syzkaller-bugs@googlegroups.com, Stefan Hajnoczi Subject: [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check Message-ID: <20180409174731-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180409131021.5132-1-stefanha@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stefan Hajnoczi Commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ("vhost: validate log when IOTLB is enabled") introduced a regression. The logic was originally: if (vq->iotlb) return 1; return A && B; After the patch the short-circuit logic for A was inverted: if (A || vq->iotlb) return A; return B; The correct logic is: if (!A || vq->iotlb) return A; return B; Reported-by: syzbot+65a84dde0214b0387ccd@syzkaller.appspotmail.com Cc: Jason Wang Signed-off-by: Stefan Hajnoczi Acked-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 5320039671b7..f6af4210679a 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1246,7 +1246,7 @@ int vhost_vq_access_ok(struct vhost_virtqueue *vq) { int ret = vq_log_access_ok(vq, vq->log_base); - if (ret || vq->iotlb) + if (!ret || vq->iotlb) return ret; return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); -- 2.14.3