From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752185AbeBAPQK (ORCPT ); Thu, 1 Feb 2018 10:16:10 -0500 Received: from foss.arm.com ([217.140.101.70]:51380 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751788AbeBAPQH (ORCPT ); Thu, 1 Feb 2018 10:16:07 -0500 Subject: Re: [PATCH] soc: mediatek: Handle return of of_match_device function To: Geert Uytterhoeven Cc: Himanshu Jha , Matthias Brugger , Ulf Hansson , Weiyi Lu , Geert Uytterhoeven , sean.wang@mediatek.com, Linux Kernel Mailing List , kevin-cw.chen@mediatek.com, Cheng Mars , linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org References: <1517482822-28758-1-git-send-email-himanshujha199640@gmail.com> From: Robin Murphy Message-ID: <5fe8a04b-de13-87fb-2916-f3d26e320c4d@arm.com> Date: Thu, 1 Feb 2018 15:16:03 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/02/18 15:09, Geert Uytterhoeven wrote: > On Thu, Feb 1, 2018 at 4:02 PM, Robin Murphy wrote: >> On 01/02/18 11:00, Himanshu Jha wrote: >>> In scpsys_probe function, return value of of_match_device function which >>> returns null is dereferenced without checking. Therefore, add a check for >>> potential null dereference. >>> >>> Detected by CoverityScan, CID#1424087 "Dereference null return value" >>> >>> Fixes: commit 53fddb1a66dd ("soc: mediatek: reduce code duplication of >>> scpsys_probe across all SoCs") >>> Signed-off-by: Himanshu Jha >>> --- >>> drivers/soc/mediatek/mtk-scpsys.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/drivers/soc/mediatek/mtk-scpsys.c >>> b/drivers/soc/mediatek/mtk-scpsys.c >>> index 435ce5e..6e7f196 100644 >>> --- a/drivers/soc/mediatek/mtk-scpsys.c >>> +++ b/drivers/soc/mediatek/mtk-scpsys.c >>> @@ -981,6 +981,9 @@ static int scpsys_probe(struct platform_device *pdev) >>> int i, ret; >>> match = of_match_device(of_scpsys_match_tbl, &pdev->dev); >>> + if (!match) >>> + return -EINVAL; >>> + >>> soc = (const struct scp_soc_data *)match->data; >> >> You could of course replace the whole sequence with an >> of_device_get_match_data() call, which happens to be inherently safe against >> the no-match case even when that *is* impossible by design. > > +1 > >>> scp = init_scp(pdev, soc->domains, soc->num_domains, &soc->regs, > > ... followed by the static analyser gang complaining we may dereference > NULL pointer soc... Well, if the static analysers can't track the provenance of dev->driver->of_match_table, let's keep ignoring them until they get cleverer :P Robin. > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds >