From nobody Tue Nov 4 23:31:01 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 153174614973649.61310420495056; Mon, 16 Jul 2018 06:02:29 -0700 (PDT) Received: from localhost ([::1]:51259 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ff392-0002hZ-64 for importer@patchew.org; Mon, 16 Jul 2018 09:02:28 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43344) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ff36Q-000167-Mk for qemu-devel@nongnu.org; Mon, 16 Jul 2018 08:59:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ff36P-00023J-NW for qemu-devel@nongnu.org; Mon, 16 Jul 2018 08:59:46 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35414 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ff36N-000215-4E; Mon, 16 Jul 2018 08:59:43 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8BFF37C6A9; Mon, 16 Jul 2018 12:59:42 +0000 (UTC) Received: from thh440s.str.redhat.com (dhcp-200-180.str.redhat.com [10.33.200.180]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB6101C589; Mon, 16 Jul 2018 12:59:40 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Peter Maydell , Paolo Bonzini Date: Mon, 16 Jul 2018 14:59:20 +0200 Message-Id: <1531745974-17187-4-git-send-email-thuth@redhat.com> In-Reply-To: <1531745974-17187-1-git-send-email-thuth@redhat.com> References: <1531745974-17187-1-git-send-email-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 16 Jul 2018 12:59:42 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Mon, 16 Jul 2018 12:59:42 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'thuth@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v3 03/17] hw/arm/bcm2836: Fix crash with device_add bcm2837 on unsupported machines 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: Eduardo Habkost , Alistair Francis , Markus Armbruster , Subbaraya Sundeep , Beniamino Galvani , qemu-arm@nongnu.org, "Edgar E. Iglesias" , =?UTF-8?q?Andreas=20F=C3=A4rber?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When trying to "device_add bcm2837" on a machine that is not suitable for this device, you can quickly crash QEMU afterwards, e.g. with "info qtree": echo "{'execute':'qmp_capabilities'} {'execute':'device_add', " \ "'arguments':{'driver':'bcm2837'}} {'execute': 'human-monitor-command', " \ "'arguments': {'command-line': 'info qtree'}}" | \ aarch64-softmmu/qemu-system-aarch64 -M integratorcp,accel=3Dqtest -S -qmp = stdio {"QMP": {"version": {"qemu": {"micro": 50, "minor": 12, "major": 2}, "package": "build-all"}, "capabilities": []}} {"return": {}} {"error": {"class": "GenericError", "desc": "Device 'bcm2837' can not be hotplugged on this machine"}} Segmentation fault (core dumped) The qdev_set_parent_bus() from instance_init adds a link to the child devic= es which is not valid anymore after the bcm2837 instance has been destroyed. Unfortunately, the child devices do not get destroyed / unlinked correctly because both object_initialize() and object_property_add_child() increase the reference count of the child objects by one, but only one reference is dropped when the parent gets removed. So let's use the new functions object_initialize_child() and sysbus_init_child_obj() instead to create the objects, which will take care of creating the child objects with the correct reference count of one. Reviewed-by: Richard Henderson Reviewed-by: Paolo Bonzini Reviewed-by: Eduardo Habkost Signed-off-by: Thomas Huth --- hw/arm/bcm2836.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/hw/arm/bcm2836.c b/hw/arm/bcm2836.c index 6805a7d..2595d93 100644 --- a/hw/arm/bcm2836.c +++ b/hw/arm/bcm2836.c @@ -51,25 +51,19 @@ static void bcm2836_init(Object *obj) int n; =20 for (n =3D 0; n < BCM283X_NCPUS; n++) { - object_initialize(&s->cpus[n], sizeof(s->cpus[n]), - info->cpu_type); - object_property_add_child(obj, "cpu[*]", OBJECT(&s->cpus[n]), - &error_abort); + object_initialize_child(obj, "cpu[*]", &s->cpus[n], sizeof(s->cpus= [n]), + info->cpu_type, &error_abort, NULL); } =20 - object_initialize(&s->control, sizeof(s->control), TYPE_BCM2836_CONTRO= L); - object_property_add_child(obj, "control", OBJECT(&s->control), NULL); - qdev_set_parent_bus(DEVICE(&s->control), sysbus_get_default()); + sysbus_init_child_obj(obj, "control", &s->control, sizeof(s->control), + TYPE_BCM2836_CONTROL); =20 - object_initialize(&s->peripherals, sizeof(s->peripherals), - TYPE_BCM2835_PERIPHERALS); - object_property_add_child(obj, "peripherals", OBJECT(&s->peripherals), - &error_abort); + sysbus_init_child_obj(obj, "peripherals", &s->peripherals, + sizeof(s->peripherals), TYPE_BCM2835_PERIPHERALS= ); object_property_add_alias(obj, "board-rev", OBJECT(&s->peripherals), "board-rev", &error_abort); object_property_add_alias(obj, "vcram-size", OBJECT(&s->peripherals), "vcram-size", &error_abort); - qdev_set_parent_bus(DEVICE(&s->peripherals), sysbus_get_default()); } =20 static void bcm2836_realize(DeviceState *dev, Error **errp) --=20 1.8.3.1