From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32808) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bUXGM-0007vh-Gm for qemu-devel@nongnu.org; Tue, 02 Aug 2016 06:49:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bUXGG-0001NT-GW for qemu-devel@nongnu.org; Tue, 02 Aug 2016 06:49:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46564) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bUXGG-0001NP-Al for qemu-devel@nongnu.org; Tue, 02 Aug 2016 06:49:24 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D68B680082 for ; Tue, 2 Aug 2016 10:49:23 +0000 (UTC) From: Igor Mammedov Date: Tue, 2 Aug 2016 12:49:20 +0200 Message-Id: <1470134960-87851-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v2] qdev: Fix use after free in qdev_init_nofail error path List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: jsnow@redhat.com, ehabkost@redhat.com, famz@redhat.com, pbonzini@redhat.com Since 69382d8b (qdev: Fix object reference leak in case device.realize() fails), object_property_set_bool releases the device object in case realize's failed and device hasn't explicitly assigned parent. It happens due to object_unparent() on error handling path releases not only implicitly set parent but also calls device_unparent() which releases the remaining reference hold buy parent bus. qdev_try_create() created device has only 1 reference hold by parent bus which makes impossible to unparent/re-parent object without destroying it. Fix it by making caller of qdev_try_create()/qdev_init_nofail() own a reference from object_new() until qdev_init_nofail() is successfully executed so that uparenting won't destroy device until caller owns pointer returned by qdev_try_create(). Signed-off-by: Igor Mammedov --- hw/core/qdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/core/qdev.c b/hw/core/qdev.c index ee4a083..0139d67 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -151,7 +151,6 @@ DeviceState *qdev_try_create(BusState *bus, const char *type) } qdev_set_parent_bus(dev, bus); - object_unref(OBJECT(dev)); return dev; } @@ -360,6 +359,7 @@ void qdev_init_nofail(DeviceState *dev) object_get_typename(OBJECT(dev))); exit(1); } + object_unref(OBJECT(dev)); } void qdev_machine_creation_done(void) -- 2.7.4