From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758351AbcLVGSd (ORCPT ); Thu, 22 Dec 2016 01:18:33 -0500 Received: from verein.lst.de ([213.95.11.211]:53633 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751148AbcLVGSb (ORCPT ); Thu, 22 Dec 2016 01:18:31 -0500 Date: Thu, 22 Dec 2016 07:18:27 +0100 From: Christoph Hellwig To: Linus Torvalds Cc: Dave Chinner , Chris Leech , Linux Kernel Mailing List , Lee Duncan , open-iscsi@googlegroups.com, Linux SCSI List , linux-block@vger.kernel.org, Christoph Hellwig Subject: Re: [4.10, panic, regression] iscsi: null pointer deref at iscsi_tcp_segment_done+0x20d/0x2e0 Message-ID: <20161222061827.GA31630@lst.de> References: <20161214222411.GH4326@dastard> <20161214222953.GI4326@dastard> <20161216185906.t2wmrr6wqjdsrduw@straylight.hirudinean.org> <20161221221638.GD4758@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 21, 2016 at 03:19:15PM -0800, Linus Torvalds wrote: > Looking around a bit, the only even halfway suspicious scatterlist > initialization thing I see is commit f9d03f96b988 ("block: improve > handling of the magic discard payload") which used to have a magic > hack wrt !bio->bi_vcnt, and that got removed. See __blk_bios_map_sg(), > now it does __blk_bvec_map_sg() instead. But that check was only for discard (and discard-like) bios which had the maic single page that sometimes was unused attached. For "normal" bios the for_each_segment loop iterates over bi_vcnt, so it will be ignored anyway. That being said both I and the lists got CCed halfway through the thread and I haven't seen the original report, so I'm not really sure what's going on here anyway.