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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E57AC433F5 for ; Tue, 31 May 2022 01:38:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243434AbiEaBiS (ORCPT ); Mon, 30 May 2022 21:38:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233538AbiEaBiQ (ORCPT ); Mon, 30 May 2022 21:38:16 -0400 Received: from mail.meizu.com (edge07.meizu.com [112.91.151.210]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8393E60D9A for ; Mon, 30 May 2022 18:38:15 -0700 (PDT) Received: from IT-EXMB-1-125.meizu.com (172.16.1.125) by mz-mail11.meizu.com (172.16.1.15) with Microsoft SMTP Server (TLS) id 14.3.487.0; Tue, 31 May 2022 09:38:04 +0800 Received: from [172.16.137.70] (172.16.137.70) by IT-EXMB-1-125.meizu.com (172.16.1.125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Tue, 31 May 2022 09:38:03 +0800 Message-ID: <45fce6db-2e9d-0e0e-3a71-97575d7bb722@meizu.com> Date: Tue, 31 May 2022 09:38:03 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH] drm/nouveau/therm: Fix pointer dereferenced before checking To: Ben Skeggs , Karol Herbst , "Lyude Paul" , David Airlie , Daniel Vetter CC: , , References: <1653880246-23670-1-git-send-email-baihaowen@meizu.com> From: baihaowen In-Reply-To: <1653880246-23670-1-git-send-email-baihaowen@meizu.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [172.16.137.70] X-ClientProxiedBy: IT-EXMB-1-126.meizu.com (172.16.1.126) To IT-EXMB-1-125.meizu.com (172.16.1.125) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/5/30 上午11:10, Haowen Bai 写道: > The fan->base is dereferencing before null checking, so move > it after checking. > > Signed-off-by: Haowen Bai > --- > drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c > index 340f37a299dc..b13ba9b2f6be 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c > @@ -98,10 +98,10 @@ nvkm_fanpwm_create(struct nvkm_therm *therm, struct dcb_gpio_func *func) > return -ENODEV; > > fan = kzalloc(sizeof(*fan), GFP_KERNEL); > - therm->fan = &fan->base; > if (!fan) > return -ENOMEM; > > + therm->fan = &fan->base; > fan->base.type = "PWM"; > fan->base.get = nvkm_fanpwm_get; > fan->base.set = nvkm_fanpwm_set; Sorry, plz ignore this patch. fan->base is dereferenced, &fan->base is just a pointer math for pointer address offset, so it would not cause a bug(dereferencing null pointer). -- Haowen Bai