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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 DAA87C433E6 for ; Tue, 2 Feb 2021 09:26:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97E1260C3E for ; Tue, 2 Feb 2021 09:26:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232930AbhBBJ0h (ORCPT ); Tue, 2 Feb 2021 04:26:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229975AbhBBJ00 (ORCPT ); Tue, 2 Feb 2021 04:26:26 -0500 Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF99DC0613D6 for ; Tue, 2 Feb 2021 01:25:45 -0800 (PST) Received: by mail-wr1-x436.google.com with SMTP id b3so1507195wrj.5 for ; Tue, 02 Feb 2021 01:25:45 -0800 (PST) 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:in-reply-to; bh=a1OCFu7h0TcIowMDv7zHkZMNSiLVb4YwniBrbKA3xlU=; b=uF0X2tH0q3rC8OeRvULloT49lCKeBEQIIw6QI9tlhujC4RF3Y6JwL4phRurV64uvih vIy/Bkwwwa+OwUknuhm87RzJbo3TmKLf4F4bTWnWohj0xvbesjcgJf0vvzfBB/IuDpr2 T5sGY0IN4mRqFiNIkf4AjHGbM1BMcLte31RgDWX4v3q3MchbIgY1ke2jBZT8K57WRNa5 pIM1hekoQS2WUKBuoyDGNSrnzcifBgBLcCwgYgsxQpKhEok5Eamv5Ksvda7NJQk69CUw d2ITCAYRN0sV3AErdVtbrN7+deweE3u94fcS9QmF00PXgEkmZJ1YQlK7NALcXBFTO2LM R6bg== 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:in-reply-to; bh=a1OCFu7h0TcIowMDv7zHkZMNSiLVb4YwniBrbKA3xlU=; b=Y4Q4GvXfAICVGGq5KikDgNxK7E91B92nm+334A14TlJW2t/jDqxSIoDkyrF1pMso7a rXVmOW1U9j8pYNC8/kn4fBbldj3NQdzY8WUiR9ssJd4Q2gyrdYl6dv27OvKtyATpYq1y v3qyGIvscnFJa1HH/QzSdaHDzYezOsvq4RHP4rRGUjklVYUcnNRIsu5NHY7yerrgSaq1 zXKYgpfx5YLL+5ynw0sUV5FrA9BlloTupZzjhzbN8H5mUceFnGTeMn6l+LWMcYfckK8t ISv1q7dEvS9f0rSF7YENZVb3TZM8DExSEcpk6lWChMZ/+h0Kp+mjLEEwAFlVbCiGbsu3 jsJg== X-Gm-Message-State: AOAM532bUPRbey1xuTDiPmxBAUEQXeW5ChJ2gh0adVy/KqQtyVERipCZ HU4DA/R3fQyub5eJscdgWisDrg== X-Google-Smtp-Source: ABdhPJy7kfZ4o7WstsegOSMCSFJFOfW1Ibzofjf5AFjyCjsHJFeZ5+FIwpQN0elV9b07P6x7DgPmdw== X-Received: by 2002:adf:fc8a:: with SMTP id g10mr23343632wrr.189.1612257944619; Tue, 02 Feb 2021 01:25:44 -0800 (PST) Received: from maple.lan (cpc141216-aztw34-2-0-cust174.18-1.cable.virginm.net. [80.7.220.175]) by smtp.gmail.com with ESMTPSA id q24sm2040048wmq.24.2021.02.02.01.25.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Feb 2021 01:25:43 -0800 (PST) Date: Tue, 2 Feb 2021 09:25:41 +0000 From: Daniel Thompson To: Wenjia Zhao Cc: Lee Jones , Jingoo Han , Bartlomiej Zolnierkiewicz , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] backlight: pcf50633: pdata may be a null pointer, null pointer dereference cause crash Message-ID: <20210202092541.2wvzpe53mavrd47x@maple.lan> References: <1612190499-73818-1-git-send-email-driverfuzzing@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1612190499-73818-1-git-send-email-driverfuzzing@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 01, 2021 at 08:41:38AM -0600, Wenjia Zhao wrote: > Signed-off-by: Wenjia Zhao There should be a patch description here explaining why the patch is needed and how it works. > --- > drivers/video/backlight/pcf50633-backlight.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/video/backlight/pcf50633-backlight.c b/drivers/video/backlight/pcf50633-backlight.c > index 540dd338..43267af 100644 > --- a/drivers/video/backlight/pcf50633-backlight.c > +++ b/drivers/video/backlight/pcf50633-backlight.c > @@ -127,7 +127,8 @@ static int pcf50633_bl_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, pcf_bl); > > - pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time); > + if (pdata) > + pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time); Assuming you found this issue using a static analyzer then I think it might be better to if an "if (!pdata) return -EINVAL" further up the file instead. In other words it is better to "document" (via the return code) that the code does not support pdata == NULL than to add another untested code path. Daniel.