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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8ABAFC433B4 for ; Fri, 9 Apr 2021 16:11:17 +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 1BF1E600D4 for ; Fri, 9 Apr 2021 16:11:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BF1E600D4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:37118 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUtj2-0000VD-2T for qemu-devel@archiver.kernel.org; Fri, 09 Apr 2021 12:11:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46538) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUtbs-0001CU-QS for qemu-devel@nongnu.org; Fri, 09 Apr 2021 12:03:52 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:25938) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUtbr-0006B7-AK for qemu-devel@nongnu.org; Fri, 09 Apr 2021 12:03:52 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-386-YR73Y4-ePRGjhmw8aXBz5A-1; Fri, 09 Apr 2021 12:03:46 -0400 X-MC-Unique: YR73Y4-ePRGjhmw8aXBz5A-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id AEDB81883533; Fri, 9 Apr 2021 16:03:45 +0000 (UTC) Received: from bahia.redhat.com (ovpn-114-173.ams2.redhat.com [10.36.114.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id E5D825C230; Fri, 9 Apr 2021 16:03:43 +0000 (UTC) From: Greg Kurz To: qemu-devel@nongnu.org Subject: [PATCH 2/2] cpu/core: Fix "help" of CPU core device types Date: Fri, 9 Apr 2021 18:03:39 +0200 Message-Id: <20210409160339.500167-3-groug@kaod.org> In-Reply-To: <20210409160339.500167-1-groug@kaod.org> References: <20210409160339.500167-1-groug@kaod.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=groug@kaod.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kaod.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=WINDOWS-1252 Received-SPF: softfail client-ip=205.139.111.44; envelope-from=groug@kaod.org; helo=us-smtp-delivery-44.mimecast.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no autolearn_force=no X-Spam_action: no action 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@linaro.org, Thomas Huth , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , Markus Armbruster , Greg Kurz , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Calling qdev_get_machine() from a QOM instance_init function is fragile because we can't be sure the machine object actually exists. And this happens to break when passing ",help" on the command line to get the list of properties for a CPU core device types : $ ./qemu-system-ppc64 -device power8_v2.0-spapr-cpu-core,help qemu-system-ppc64: ../../hw/core/machine.c:1290: qdev_get_machine: Assertion `machine !=3D NULL' failed. Aborted (core dumped) This used to work before QEMU 5.0, but commit 3df261b6676b unwillingly introduced a subtle regression : the above command line needs to create an instance but the instance_init function of the base class calls qdev_get_machine() before qemu_create_machine() has been called, which is a programming bug. Use current_machine instead. It is okay to skip the setting of nr_thread in this case since only its type is displayed. Reported-by: Thomas Huth Fixes: 3df261b6676b ("softmmu/vl.c: Handle '-cpu help' and '-device help' b= efore 'no default machine'") Cc: peter.maydell@linaro.org Signed-off-by: Greg Kurz --- hw/cpu/core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/cpu/core.c b/hw/cpu/core.c index 92d3b2fbad62..987607515574 100644 --- a/hw/cpu/core.c +++ b/hw/cpu/core.c @@ -66,10 +66,16 @@ static void core_prop_set_nr_threads(Object *obj, Visit= or *v, const char *name, =20 static void cpu_core_instance_init(Object *obj) { - MachineState *ms =3D MACHINE(qdev_get_machine()); CPUCore *core =3D CPU_CORE(obj); =20 - core->nr_threads =3D ms->smp.threads; + /* + * Only '-device something-cpu-core,help' can get us there before + * the machine has been created. We don't care to set nr_threads + * in this case since it isn't used afterwards. + */ + if (current_machine) { + core->nr_threads =3D current_machine->smp.threads; + } } =20 static void cpu_core_class_init(ObjectClass *oc, void *data) --=20 2.26.3