From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:36817) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hDcr8-0004Y8-Hq for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hDcr6-0005cz-FA for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52790) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hDcr6-0005Xy-0x for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:08 -0400 Date: Mon, 8 Apr 2019 19:26:01 -0300 From: Eduardo Habkost Message-ID: <20190408222601.GR7238@habkost.net> References: <20190407092314.11066-1-thuth@redhat.com> <20190408134517.GA9047@richard> <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-4.0] hw/i386/pc: Fix crash when hot-plugging nvdimm on older machine types List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: Wei Yang , Xiao Guangrong , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Paolo Bonzini On Mon, Apr 08, 2019 at 05:06:49PM +0200, Thomas Huth wrote: > On 08/04/2019 15.45, Wei Yang wrote: [...] > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > > index 6077d27361..b11f3b15c1 100644 > > --- a/hw/i386/pc.c > > +++ b/hw/i386/pc.c > > @@ -2091,6 +2091,9 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > > } > > > > hotplug_handler_pre_plug(pcms->acpi_dev, dev, errp); > > + if (*errp) { > > + return; > > + } > > Not sure, but I think you can not rely on the fact that the caller set > *errp = NULL already... that's why it is more common to use a local_err > variable and error_propagate() for such cases (which is what I did in my > patch). *errp can't be non-NULL (otherwise functions calling error_setg() would crash). errp can be NULL, though, and that's why you need a local_err variable. I'd love to eliminate NULL errp from our codebase, but I couldn't find a way to do it that is safe and simple (i.e. not letting us pass NULL errp by mistake and not requiring a macro wrapping every `&local_err` expression). -- Eduardo 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=-5.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 25BEDC10F13 for ; Mon, 8 Apr 2019 22:37:13 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E4417213F2 for ; Mon, 8 Apr 2019 22:37:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4417213F2 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 ([127.0.0.1]:59969 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hDct6-0005bf-8o for qemu-devel@archiver.kernel.org; Mon, 08 Apr 2019 18:37:12 -0400 Received: from eggs.gnu.org ([209.51.188.92]:36817) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hDcr8-0004Y8-Hq for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hDcr6-0005cz-FA for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52790) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hDcr6-0005Xy-0x for qemu-devel@nongnu.org; Mon, 08 Apr 2019 18:35:08 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 578DF30821C0; Mon, 8 Apr 2019 22:26:06 +0000 (UTC) Received: from localhost (ovpn-116-14.gru2.redhat.com [10.97.116.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id B01015D9C9; Mon, 8 Apr 2019 22:26:03 +0000 (UTC) Date: Mon, 8 Apr 2019 19:26:01 -0300 From: Eduardo Habkost To: Thomas Huth Message-ID: <20190408222601.GR7238@habkost.net> References: <20190407092314.11066-1-thuth@redhat.com> <20190408134517.GA9047@richard> <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Mon, 08 Apr 2019 22:26:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH for-4.0] hw/i386/pc: Fix crash when hot-plugging nvdimm on older machine types X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, Paolo Bonzini , "Michael S. Tsirkin" , Wei Yang , Xiao Guangrong Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190408222601.iegtCw1JL0TMemNXW8QmzF2OrI0E5K2T3DOMXQHISq0@z> On Mon, Apr 08, 2019 at 05:06:49PM +0200, Thomas Huth wrote: > On 08/04/2019 15.45, Wei Yang wrote: [...] > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > > index 6077d27361..b11f3b15c1 100644 > > --- a/hw/i386/pc.c > > +++ b/hw/i386/pc.c > > @@ -2091,6 +2091,9 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > > } > > > > hotplug_handler_pre_plug(pcms->acpi_dev, dev, errp); > > + if (*errp) { > > + return; > > + } > > Not sure, but I think you can not rely on the fact that the caller set > *errp = NULL already... that's why it is more common to use a local_err > variable and error_propagate() for such cases (which is what I did in my > patch). *errp can't be non-NULL (otherwise functions calling error_setg() would crash). errp can be NULL, though, and that's why you need a local_err variable. I'd love to eliminate NULL errp from our codebase, but I couldn't find a way to do it that is safe and simple (i.e. not letting us pass NULL errp by mistake and not requiring a macro wrapping every `&local_err` expression). -- Eduardo