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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E6453C7619A for ; Thu, 23 Mar 2023 13:59:10 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pfLSW-0000Bb-Ty; Thu, 23 Mar 2023 09:58:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pfLSV-0000B7-4h for qemu-devel@nongnu.org; Thu, 23 Mar 2023 09:58:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pfLST-00088j-IH for qemu-devel@nongnu.org; Thu, 23 Mar 2023 09:58:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679579904; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=D1W3DHp3xspmY5hdu5czMWy056gRsu9LM5k0US6jbuA=; b=i40YjbkEuxmpxqZCXylCgiwo6/tp6CPUC+8aTE8/UTf6f3JhlctSWldJQrJW2Ybz6gEyJF qEgbfWl0HB1+rixhXz+SKWKP0Vtr/IkhuJDzBK+V9QJwY18Gfs71sZw65CmclXnnqzSVpo QZnJJeHjSgVvvwCEMxR2OvI/mBsdwHs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-45-wFG-vdJQPfCfz51UHQXQUQ-1; Thu, 23 Mar 2023 09:58:22 -0400 X-MC-Unique: wFG-vdJQPfCfz51UHQXQUQ-1 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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id DA5D8830FB0; Thu, 23 Mar 2023 13:58:21 +0000 (UTC) Received: from localhost (unknown [10.39.195.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2CD4718EC7; Thu, 23 Mar 2023 13:58:20 +0000 (UTC) Date: Thu, 23 Mar 2023 09:58:19 -0400 From: Stefan Hajnoczi To: Paolo Bonzini Cc: qemu-devel , "open list:Block layer core" , Fam Zheng , qemu-stable , Qing Wang Subject: Re: [PATCH for-8.0] aio-posix: fix race between epoll upgrade and aio_set_fd_handler() Message-ID: <20230323135819.GA1331422@fedora> References: <20230322145521.1294954-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Trv9uuz69zfZMbP2" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --Trv9uuz69zfZMbP2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 23, 2023 at 06:02:36AM +0100, Paolo Bonzini wrote: > Il mer 22 mar 2023, 15:55 Stefan Hajnoczi ha scritt= o: >=20 > > + /* The list must not change while we add fds to epoll */ > > + if (!qemu_lockcnt_dec_if_lock(&ctx->list_lock)) { > > + return false; > > + } > > + > > + ok =3D fdmon_epoll_try_enable(ctx); > > + > > + qemu_lockcnt_unlock(&ctx->list_lock); > > >=20 > Shouldn't this be inc_and_unlock to balance the change made by dec_if_loc= k? Yes, the caller expects list_lock to still be incremented. Thanks for catching this! Stefan --Trv9uuz69zfZMbP2 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmQcWvsACgkQnKSrs4Gr c8h4HwgAmWR/S40fAci3MOSb8ERlBpNK8/JAZhajCadRSJ/+5DgzIyBM+af3Mx8h TE/lvNaZKVq8wXy4rZEkK0TK3gGXb25mcV6kgL52wBsJpmyIGWhxT9ldZOp+BwKf M276/761+omf697ZWoZJWtkJ0FgkDhpbS2QDF3VbKPiv+V0gea5DDFG7lJCtx4Od hh3/6JTt8JRzpsqF/VOvy62zjt7whVPLxwkH6nkJJauGOnY/rjtJDpQM8GWyslCe 3+ciu/UsqOIDbUdFruqHE5Yn4iZGfySXtFn71gTj3VecC4WOwUSu/kkh2UAOeFq6 xk/SDLOcXva4tYFoxv6QJ8a4tVx9lg== =m9uz -----END PGP SIGNATURE----- --Trv9uuz69zfZMbP2--