From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26D9AC49ED7 for ; Sat, 21 Sep 2019 10:18:08 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F1454208C0 for ; Sat, 21 Sep 2019 10:18:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1454208C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40692 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iBcSt-0004TN-3H for qemu-devel@archiver.kernel.org; Sat, 21 Sep 2019 06:18:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45284) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iBcS2-0003wb-44 for qemu-devel@nongnu.org; Sat, 21 Sep 2019 06:17:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iBcS0-0006J0-Fv for qemu-devel@nongnu.org; Sat, 21 Sep 2019 06:17:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55782) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iBcS0-0006Ib-Ah; Sat, 21 Sep 2019 06:17:12 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4401B18C4275; Sat, 21 Sep 2019 10:17:11 +0000 (UTC) Received: from x1w.redhat.com (ovpn-204-61.brq.redhat.com [10.40.204.61]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4C9DB5C1B5; Sat, 21 Sep 2019 10:17:06 +0000 (UTC) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-trivial@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH] hw/ptimer: Assert next_event is newer than last_event Date: Sat, 21 Sep 2019 12:17:03 +0200 Message-Id: <20190921101703.17935-1-philmd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.62]); Sat, 21 Sep 2019 10:17:11 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Dmitry Osipenko , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" If the period is too big, the 'delta * period' product result might overflow, resulting in a negative number, then the next_event ends before the last_event. This is buggy, as there is no forward progress. Assert this can not happen. Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- hw/core/ptimer.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c index d58e2dfdb0..88085d4c81 100644 --- a/hw/core/ptimer.c +++ b/hw/core/ptimer.c @@ -125,6 +125,9 @@ static void ptimer_reload(ptimer_state *s, int delta_= adjust) =20 s->last_event =3D s->next_event; s->next_event =3D s->last_event + delta * period; + /* Verify forward progress */ + g_assert(s->next_event > s->last_event); + if (period_frac) { s->next_event +=3D ((int64_t)period_frac * delta) >> 32; } --=20 2.20.1