From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: BUG: unable to handle kernel NULL pointer dereference in mem16_serial_out Date: Thu, 12 Dec 2019 11:57:54 +0100 Message-ID: <20191212105754.GC1476206@kroah.com> References: <00000000000044a65205994a7e13@google.com> <00000000000003cc8505994f9036@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <00000000000003cc8505994f9036@google.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-api@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