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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 98282C2BA2B for ; Thu, 16 Apr 2020 20:41:05 +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 61EFC221F4 for ; Thu, 16 Apr 2020 20:41:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Z20H8sUG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61EFC221F4 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 ([::1]:39128 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jPBJo-0004wf-Ju for qemu-devel@archiver.kernel.org; Thu, 16 Apr 2020 16:41:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60524) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jPBFh-0008FD-NU for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jPBFg-000487-Ps for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:49 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:44903 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jPBFg-00047l-Mp for qemu-devel@nongnu.org; Thu, 16 Apr 2020 16:36:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587069408; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2RHcLfzv/AHZUi5OBodeG6jtQjhpZVEt+eRcfP9lsEw=; b=Z20H8sUGQBZuPRqNv/tKe6PR5Qj5rCRxxyxN8Q9HzS4CHsjPaQTgSE0CtBXi2Myvy00niJ Ih/4Krfaw4+JeDhoPE/rZ5KESigzZLr/Atq9VNhF6XxiSvU3py1fPB1b+Jb2vpHoVeFN67 yicGyMcHsmhIibijH37d/c0pvc3nncw= 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-141-d8kh3UcoPWaZFPyePOHkqg-1; Thu, 16 Apr 2020 16:36:39 -0400 X-MC-Unique: d8kh3UcoPWaZFPyePOHkqg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7124B18C43C1; Thu, 16 Apr 2020 20:36:38 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8F8DAA099C; Thu, 16 Apr 2020 20:36:36 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH 3/4] device-core: use atomic_set on .realized property Date: Thu, 16 Apr 2020 23:36:23 +0300 Message-Id: <20200416203624.32366-4-mlevitsk@redhat.com> In-Reply-To: <20200416203624.32366-1-mlevitsk@redhat.com> References: <20200416203624.32366-1-mlevitsk@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: Fam Zheng , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , "Michael S. Tsirkin" , Maxim Levitsky , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Some code might race with placement of new devices on a bus. We currently first place a (unrealized) device on the bus and then realize it. As a workaround, users that scan the child device list, can check the realized property to see if it is safe to access such a device. Use an atomic write here too to aid with this. A separate discussion is what to do with devices that are unrealized: It looks like for this case we only call the hotplug handler's unplug callback and its up to it to unrealize the device. An atomic operation doesn't cause harm for this code path though. Signed-off-by: Maxim Levitsky --- 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 f0c87e582e..bbb1ae3eb3 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -983,7 +983,7 @@ static void device_set_realized(Object *obj, bool value= , Error **errp) } =20 assert(local_err =3D=3D NULL); - dev->realized =3D value; + atomic_set(&dev->realized, value); return; =20 child_realize_fail: --=20 2.17.2