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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 398B4C2D0C8 for ; Thu, 12 Dec 2019 10:57:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05532227BF for ; Thu, 12 Dec 2019 10:57:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576148279; bh=efVjjQG6UNoj6c0lJ3KZywfrNSIcf/ci6H+eEgtsTEg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=mMH/y1OE5LFWAYni+GoKrST3SV6Hwa4WZjLl0tyW5F/9xSz6x++0QKTM2B23XQNYp a/h7IYORkbOpZI6CdvxoF08Yjf+mpMf5sGiz1DkZvrLEwjBCKiezvxhkKXK8ADCP5r whJ1du9LSRzMEyfd/MqYhVCW0AZmbJ9LhQDYLhdg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728932AbfLLK55 (ORCPT ); Thu, 12 Dec 2019 05:57:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:49512 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728784AbfLLK54 (ORCPT ); Thu, 12 Dec 2019 05:57:56 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A7ED9214D8; Thu, 12 Dec 2019 10:57:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576148276; bh=efVjjQG6UNoj6c0lJ3KZywfrNSIcf/ci6H+eEgtsTEg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qIZUGbB5HlPD3M7fra6t0v3E4z6A2gSNs+Dumsk/xrse3/DeZY82vaPqiZhADE+dH WC1Z5XodnJcXvvoBUdYmPO2tlMtHQKnw6ENXgegzU7YTy7Fm1bCxt4w1h++/yiz6VG 2MwBCnXujAaYG6EHQ8hxaIJ+LVuQ7fskCptM8H9Q= Date: Thu, 12 Dec 2019 11:57:54 +0100 From: Greg KH To: syzbot Cc: andriy.shevchenko@linux.intel.com, asierra@xes-inc.com, corbet@lwn.net, ext-kimmo.rautkoski@vaisala.com, jslaby@suse.com, kai.heng.feng@canonical.com, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, mika.westerberg@linux.intel.com, paulburton@kernel.org, peter@hurleysoftware.com, sr@denx.de, syzkaller-bugs@googlegroups.com, yamada.masahiro@socionext.com, yegorslists@googlemail.com Subject: Re: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out Message-ID: <20191212105754.GC1476206@kroah.com> References: <00000000000044a65205994a7e13@google.com> <00000000000003cc8505994f9036@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00000000000003cc8505994f9036@google.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 09, 2019 at 05:38:01PM -0800, syzbot wrote: > syzbot has bisected this bug to: > > commit bd94c4077a0b2ecc35562c294f80f3659ecd8499 > Author: Masahiro Yamada > Date: Wed Oct 28 03:46:05 2015 +0000 > > serial: support 16-bit register interface for console That would be because that is when this function was added to the kernel :) Again, you are asking the kernel to write to a bad place in memory, and then crash when that happens. That sounds like the correct functionality to me... thanks, greg k-h