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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 0E342C32750 for ; Tue, 30 Jul 2019 22:01:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DFA69208E3 for ; Tue, 30 Jul 2019 22:01:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387915AbfG3WBG (ORCPT ); Tue, 30 Jul 2019 18:01:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47280 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387630AbfG3WBG (ORCPT ); Tue, 30 Jul 2019 18:01:06 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1E44D4E8AC; Tue, 30 Jul 2019 22:01:06 +0000 (UTC) Received: from localhost (unknown [10.18.25.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 667E719724; Tue, 30 Jul 2019 22:01:03 +0000 (UTC) Date: Tue, 30 Jul 2019 18:01:02 -0400 From: Mike Snitzer To: Dan Williams Cc: Pankaj Gupta , device-mapper development , linux-nvdimm , linux-fsdevel , Linux Kernel Mailing List , Alasdair Kergon , jencce.kernel@gmail.com Subject: Re: dm: fix dax_dev NULL dereference Message-ID: <20190730220102.GA15604@redhat.com> References: <20190730113708.14660-1-pagupta@redhat.com> <2030283543.5419072.1564486701158.JavaMail.zimbra@redhat.com> <20190730190737.GA14873@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 30 Jul 2019 22:01:06 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Jul 30 2019 at 5:38pm -0400, Dan Williams wrote: > On Tue, Jul 30, 2019 at 12:07 PM Mike Snitzer wrote: > > > > I staged the fix (which I tweaked) here: > > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.3&id=95b9ebb78c4c733f8912a195fbd0bc19960e726e > > Thanks for picking this up Mike, but I'd prefer to just teach > dax_synchronous() to return false if the passed in dax_dev is NULL. > Thoughts? I considered that too but I moved away from it because I'm so used to the various block interfaces requiring the caller pass a non-NULL pointer (e.g. request_queue): $ grep -ri return drivers/md/dm-table.c | grep \&\& drivers/md/dm-table.c: return dev->dax_dev && dax_synchronous(dev->dax_dev); drivers/md/dm-table.c: return q && blk_queue_zoned_model(q) == *zoned_model; drivers/md/dm-table.c: return q && blk_queue_zone_sectors(q) == *zone_sectors; drivers/md/dm-table.c: return q && (q->queue_flags & flush); drivers/md/dm-table.c: return q && blk_queue_nonrot(q); drivers/md/dm-table.c: return q && !blk_queue_add_random(q); drivers/md/dm-table.c: return q && !q->limits.max_write_same_sectors; drivers/md/dm-table.c: return q && !q->limits.max_write_zeroes_sectors; drivers/md/dm-table.c: return q && !blk_queue_discard(q); drivers/md/dm-table.c: return q && !blk_queue_secure_erase(q); drivers/md/dm-table.c: return q && bdi_cap_stable_pages_required(q->backing_dev_info); I'm fine with however you'd like to skin this cat though. Just let me know and I'll keep/drop this patch accordingly. Thanks, Mike