From patchwork Mon Apr 9 13:10:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 10331309 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4330E6037F for ; Mon, 9 Apr 2018 13:10:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 37676289D5 for ; Mon, 9 Apr 2018 13:10:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2C31C28B0C; Mon, 9 Apr 2018 13:10:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CCDDE289D5 for ; Mon, 9 Apr 2018 13:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751635AbeDINKd (ORCPT ); Mon, 9 Apr 2018 09:10:33 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33112 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751367AbeDINKc (ORCPT ); Mon, 9 Apr 2018 09:10:32 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9CBFA4074CA8; Mon, 9 Apr 2018 13:10:31 +0000 (UTC) Received: from localhost (ovpn-117-227.ams2.redhat.com [10.36.117.227]) by smtp.corp.redhat.com (Postfix) with ESMTP id 76D3A10F1BF9; Mon, 9 Apr 2018 13:10:24 +0000 (UTC) From: Stefan Hajnoczi To: 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] vhost: fix vhost_vq_access_ok() log check Date: Mon, 9 Apr 2018 21:10:21 +0800 Message-Id: <20180409131021.5132-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Mon, 09 Apr 2018 13:10:31 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Mon, 09 Apr 2018 13:10:31 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'stefanha@redhat.com' RCPT:'' Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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);