From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225JRBPSd4RLd7FbFRhyqt1JSOPYnZ9JAZlinYGQp7Hw9cwcGOwEdtDueRrAYAw5JztNkDO0 ARC-Seal: i=1; a=rsa-sha256; t=1516811243; cv=none; d=google.com; s=arc-20160816; b=RQPj/V8N9JnpauD6+3fBfwRM+wuQ/ILqdYSZnfELl+pcR+vK2WxpisruRr2KxCvFjU MUJqecv7uTqY670QyxZbgZ0j+8zTuunAjE0rMoIIgRmBVtL8KR8FE2kfIghIE12JvlrY 3jVKYJJLNy/DUylBrCpu0GcEh5RJeCKuaHJmePzW1mK6bh/6GqXJZd2W7KY0yZRX5XEb J79rk2ABNUZVvCcbv2mW8YKIz0/+fkz/NXC7HorpQMIqtWx/kP3B9QK/3sgKE++RyRh0 +4BQ6cqiXn7CwlR+SruDRnes7a7UWOZ52MaZNx9cIzkMddbgejfaM/yDMjMnyX2oXiZf MouA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :dkim-signature:arc-authentication-results; bh=D5iyi60FUguZW597ibRW7tMvKHrLd5yO1GF9M+VAohA=; b=Vq7uK+jnvMCe/6VBF33igtyjw3jmMHu6VtxqMy4hk/Z1OQ8AQMc51qiF7fSQ9adf5V QZVwtcR8e0NuBikuSjtRebm6h1IMaH09NZUdA0lDY0xCOkXjjUleQegfp917yQo/nvma vCw5pUS8sdWhthVD5g5bgNnB8e/z0uwuyzqpD5MvocO+TnMm2X+ydQKDPF6Pja7pJIVK a1ou5HreH27ZLxPwFJy4ajDvn8kaaCXnEwyFNZCjGs4kYoy/+ILkoHtevxSfXoXIE+zd w0zX5i7aEZf6LHzn4aTo8u+nJj7JlRs0MaNFbak+qthlKHZ4S155TSrit6l9Uz5mfvgo shcA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@lechnology.com header.s=default header.b=B+gGMzSK; spf=pass (google.com: domain of david@lechnology.com designates 206.190.152.46 as permitted sender) smtp.mailfrom=david@lechnology.com Authentication-Results: mx.google.com; dkim=pass header.i=@lechnology.com header.s=default header.b=B+gGMzSK; spf=pass (google.com: domain of david@lechnology.com designates 206.190.152.46 as permitted sender) smtp.mailfrom=david@lechnology.com Subject: Re: [PATCH 1/2] regmap: fix NULL pointer dereference in regmap_name_read_file() To: Mark Brown , Lars-Peter Clausen Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman References: <1516748023-17235-1-git-send-email-david@lechnology.com> <1516748023-17235-2-git-send-email-david@lechnology.com> <20180124161941.GI9366@sirena.org.uk> From: David Lechner Message-ID: <5920ae0a-bdb7-7819-8e3f-32b20368a20f@lechnology.com> Date: Wed, 24 Jan 2018 10:27:22 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180124161941.GI9366@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - linuxfoundation.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590425592886901979?= X-GMAIL-MSGID: =?utf-8?q?1590491866457461964?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 01/24/2018 10:19 AM, Mark Brown wrote: > On Wed, Jan 24, 2018 at 05:14:50PM +0100, Lars-Peter Clausen wrote: >> On 01/23/2018 11:53 PM, David Lechner wrote: >>> This fixes a possible NULL pointer dereference oops in >>> regmap_name_read_file() when the regmap does not have a device >>> associated with it. > >>> - ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name); >>> + if (map->dev && map->dev->driver) >>> + name = map->dev->driver->name; >>> + >>> + ret = snprintf(buf, PAGE_SIZE, "%s\n", name); > >> Won't this print "(null)" now? Not sure if that is the best approach. > > Indeed. It is an improvement but not exactly helpful. > Would it be better if it said "this regmap does not have driver" instead of "(null)"?