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=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 187A1CA9EAF for ; Mon, 21 Oct 2019 12:40:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD0BD20882 for ; Mon, 21 Oct 2019 12:40:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="m6pK6vuf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728554AbfJUMkc (ORCPT ); Mon, 21 Oct 2019 08:40:32 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:39627 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727322AbfJUMkc (ORCPT ); Mon, 21 Oct 2019 08:40:32 -0400 Received: by mail-wm1-f65.google.com with SMTP id r141so3048805wme.4 for ; Mon, 21 Oct 2019 05:40:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=R5D7lr/7jPesG94tDWWwewjuwTYhPDAmBpCs+r4T4K4=; b=m6pK6vuf3zpfjYZiGwMjh4xEQNU8Jky+3d+vqNeRRo4QNKGmDjFmsXBFb1dsmCDt1j B4qQwOXFYqtnP6AEwzy0FmeUmbpZw2XOh6hLGKvtykf2EH3bg1xs5lsviBNA6AlfDTf5 KIq57yciKs6q4t7U2tRyWO+Yi1esIUmAFcOD28xFbEpOlDcbdMAxWrxChRzgWuqpNH2o BFKLudO/cihRDU+AeqZxue7IUaxBbsYA6l+NrebQm/GxybCbqZ2Hk+yINyEoNzgoJNFx 9/w3pGmCOWz61kvGWNHDL5RRk4s3n6H0dT9eVKYahC4yQdQEu0wXYoHgT71VAT+pWhaA V2+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=R5D7lr/7jPesG94tDWWwewjuwTYhPDAmBpCs+r4T4K4=; b=N/pzSk9Z/9+Ji2J4lXOMQFXlN49L5n29V3gKko+W9NBT6PZ3HI/IkejkhHhzoErOaW p2sgIRl7zRJEuG2JphD/LR40ibWgDl1iH/v8Zms1d6xih9tdluB98KnO42dIH+negFie D0FAD76jWpIfdxuwDFTKiTsJphizsUsyqX/pfGETpEvnADMK4jWgt9ewASlhNunNF4ok 8QkBZUZNwlw6EH2UMoXP0vp6R4JqlbIGOQUBdNZ+Qi2ywfpugx9GILL2yC7kEYfmT46T o3Vdd/Jux/ybUHTZXduBlVIaVmKJFkPSaehrvjoq8ELQnd6oOx4HFH9hn/05OukeBjjA pfDw== X-Gm-Message-State: APjAAAU89TGSrLRx9VVC6imlHDMmMVIR18hBdTUrvhV1qNWHprUJLHNK SdpnjbqfliUVlJfCKWw+SJj2Jg== X-Google-Smtp-Source: APXvYqygSkjRPrINjQ872Z7i/CXf6swgTY/j+zBGNLsSdX512ZbOY6uNqpviRydt4/B1X1h1jhbOlQ== X-Received: by 2002:a1c:c90f:: with SMTP id f15mr19843498wmb.125.1571661629651; Mon, 21 Oct 2019 05:40:29 -0700 (PDT) Received: from dell ([95.149.164.99]) by smtp.gmail.com with ESMTPSA id s14sm1100012wmh.18.2019.10.21.05.40.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 21 Oct 2019 05:40:29 -0700 (PDT) Date: Mon, 21 Oct 2019 13:40:27 +0100 From: Lee Jones To: Daniel Thompson Cc: arnd@arndb.de, broonie@kernel.org, linus.walleij@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, baohua@kernel.org, stephan@gerhold.net Subject: Re: [PATCH v2 7/9] mfd: mfd-core: Protect against NULL call-back function pointer Message-ID: <20191021124027.GG4365@dell> References: <20191021105822.20271-1-lee.jones@linaro.org> <20191021105822.20271-8-lee.jones@linaro.org> <20191021123235.royyfp4mxrvsgioh@holly.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191021123235.royyfp4mxrvsgioh@holly.lan> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Oct 2019, Daniel Thompson wrote: > On Mon, Oct 21, 2019 at 11:58:20AM +0100, Lee Jones wrote: > > If a child device calls mfd_cell_{en,dis}able() without an appropriate > > call-back being set, we are likely to encounter a panic. Avoid this > > by adding suitable checking. > > > > Signed-off-by: Lee Jones > > --- > > drivers/mfd/mfd-core.c | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c > > index 8126665bb2d8..90b43b44a15a 100644 > > --- a/drivers/mfd/mfd-core.c > > +++ b/drivers/mfd/mfd-core.c > > @@ -28,6 +28,11 @@ int mfd_cell_enable(struct platform_device *pdev) > > const struct mfd_cell *cell = mfd_get_cell(pdev); > > int err = 0; > > > > + if (!cell->enable) { > > + dev_dbg(&pdev->dev, "No .enable() call-back registered\n"); > > + return 0; > > + } > > + > > /* only call enable hook if the cell wasn't previously enabled */ > > if (atomic_inc_return(cell->usage_count) == 1) > > err = cell->enable(pdev); > > @@ -45,6 +50,11 @@ int mfd_cell_disable(struct platform_device *pdev) > > const struct mfd_cell *cell = mfd_get_cell(pdev); > > int err = 0; > > > > + if (!cell->enable) { > > Oops. > > Cancel the R-B: ;-). Shouldn't this be !cell->disable() ? Yes. Looks like a C/P error. Will fix and add your R-b. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog