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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 08063C2BA19 for ; Wed, 15 Apr 2020 16:54:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D690C208E4 for ; Wed, 15 Apr 2020 16:54:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="rH/1dp3D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1416328AbgDOQyp (ORCPT ); Wed, 15 Apr 2020 12:54:45 -0400 Received: from hqnvemgate25.nvidia.com ([216.228.121.64]:9536 "EHLO hqnvemgate25.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2410503AbgDOQyk (ORCPT ); Wed, 15 Apr 2020 12:54:40 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 15 Apr 2020 09:53:41 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 15 Apr 2020 09:54:39 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 15 Apr 2020 09:54:39 -0700 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 15 Apr 2020 16:54:39 +0000 Received: from [10.2.171.241] (10.124.1.5) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 15 Apr 2020 16:54:36 +0000 Subject: Re: [RFC PATCH v7 6/9] media: tegra: Add Tegra210 Video input driver To: Dmitry Osipenko , , , , , , CC: , , , , , References: <1586919463-30542-1-git-send-email-skomatineni@nvidia.com> <1586919463-30542-7-git-send-email-skomatineni@nvidia.com> <4118112f-f865-5460-6319-d71271fd78d1@gmail.com> From: Sowjanya Komatineni Message-ID: Date: Wed, 15 Apr 2020 09:54:35 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <4118112f-f865-5460-6319-d71271fd78d1@gmail.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To DRHQMAIL107.nvidia.com (10.27.9.16) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1586969621; bh=qoQMVbOMXWlnzPj6qRnxRISwVee7/CHgjWqtqRqD2To=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Transfer-Encoding: Content-Language; b=rH/1dp3DfCTqvWOIb14CzYUIoOBvbHu6es5/YeDMq1vuUKzUsaP0ZogLcKxkaCTAK siGgltClP2My3W8nCnSEhAz2rKh7Ms+MCFFBzBAy3OIcIYBeFcdNM+YC1jUfChofDV 6tGaIcsi5WiscfbsyhITxWJ+y7CFhtsNYhNwHJpK5t8kMyRTEz1wd0SI+elcl9Oroa KnIx9MhujgyDZa6x4zPTCoFNAkUYJY6l6UpKddVaY2VSI/igFIy8JwN5iUujfLIGOo DV1m9qtkcf53op6YPF9MvP0x84DSESxCuVxJftskbTv74WWeziFineswTyvu6iVHiD Jy32J1en+B5eg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/15/20 7:22 AM, Dmitry Osipenko wrote: > External email: Use caution opening links or attachments > > > 15.04.2020 05:57, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> +static int tegra_csi_remove(struct platform_device *pdev) >> +{ >> + struct tegra_csi *csi =3D platform_get_drvdata(pdev); >> + int err; >> + >> + err =3D host1x_client_unregister(&csi->client); >> + if (err < 0) { >> + dev_err(csi->dev, >> + "failed to unregister host1x client: %d\n", err); >> + return err; >> + } >> + >> + pm_runtime_disable(csi->dev); >> + kfree(csi); > IIRC, the driver removal is invoked on the unbinding. Hence, I'm not > sure how moving away from the resource-managed API helps here. Could you > please explain in a more details? > > Have you tried to test this driver under KASAN? I suspect that you just > masked the problem, instead of fixing it. Using devm_kzalloc for vi/csi structures based on prior feedback request=20 to switch to use kzalloc all over this driver. Hi Hans, video devices lifetime is till video device nodes are released. So, v4l2=20 device release callback does the release of tegra channel allocation=20 which hold video device. Below are the 3 possible cases of unbind/unload, 1. during tegra-video module unload, if v4l2 device refcnt is not 0=20 which is the case when any of video device node handle is kept opened=20 then unloading module will not happen and module refcnt is also non-zero=20 and unloading tegra-video module reports module in use. 2. during tegra-video driver unbind, tegra-video driver removal will do=20 vi/csi clients exit ops which unregisters video device allocated memory=20 during release callback of v4l2 device. vi/csi structure allocation=20 remains same as vi/csi driver removal will not happen in this case. 3. during direct host1x client drivers vi/csi unbind, both=20 host1x_clients vi/csi gets unregistered, deletes host1x logical device=20 which executes tegra-video driver removal() -> vi/csi exit() before=20 vi/csi memory gets freed in vi/csi driver remove(). So, any active streaming will stop and video devices are unregistered=20 during direct client driver unbind prior to freeing vi/csi memory. Also vi/csi driver remove does explicit free vi/csi as its allocated=20 with kzalloc. So not sure how using kzalloc is different to devm_kzalloc=20 for vi/csi structure in terms of when vi/csi memory gets freed? Except for channel allocation which holds video device and as video=20 device life time is beyond tegra-video module unbind->vi exit(), looks=20 like we can use devm_kzalloc for vi/csi. Can you please comment if you still think we need to use kzalloc rather=20 than devm_kzalloc for vi/csi structure allocation? Thanks Sowjanya