From patchwork Fri Jul 13 08:27:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 943331 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41RmDL0Lszz9s2M for ; Fri, 13 Jul 2018 18:28:50 +1000 (AEST) Received: from localhost ([::1]:35861 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdtRX-0002Jq-Cx for incoming@patchwork.ozlabs.org; Fri, 13 Jul 2018 04:28:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40336) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdtQp-0002Gi-0a for qemu-devel@nongnu.org; Fri, 13 Jul 2018 04:28:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fdtQn-0004OU-Vm for qemu-devel@nongnu.org; Fri, 13 Jul 2018 04:28:03 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:58124 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 1fdtQj-0004IS-DU; Fri, 13 Jul 2018 04:27:57 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 033DA72632; Fri, 13 Jul 2018 08:27:57 +0000 (UTC) Received: from thh440s.redhat.com (ovpn-116-70.ams2.redhat.com [10.36.116.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4F6EA2026D6B; Fri, 13 Jul 2018 08:27:54 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Peter Maydell , Paolo Bonzini Date: Fri, 13 Jul 2018 10:27:31 +0200 Message-Id: <1531470464-21522-4-git-send-email-thuth@redhat.com> In-Reply-To: <1531470464-21522-1-git-send-email-thuth@redhat.com> References: <1531470464-21522-1-git-send-email-thuth@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 13 Jul 2018 08:27:57 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 13 Jul 2018 08:27:57 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.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 v2 03/16] 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_F?= =?utf-8?b?w6RyYmVy?= Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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=qtest -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 devices 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. Signed-off-by: Thomas Huth Reviewed-by: Eduardo Habkost --- 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..af97b2f 100644 --- a/hw/arm/bcm2836.c +++ b/hw/arm/bcm2836.c @@ -51,25 +51,19 @@ static void bcm2836_init(Object *obj) int n; for (n = 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); } - object_initialize(&s->control, sizeof(s->control), TYPE_BCM2836_CONTROL); - 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); - 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()); } static void bcm2836_realize(DeviceState *dev, Error **errp)