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=-4.0 required=3.0 tests=BAYES_00, 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 3755DC433E6 for ; Mon, 31 Aug 2020 17:16:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AB8F206FA for ; Mon, 31 Aug 2020 17:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728829AbgHaRQz (ORCPT ); Mon, 31 Aug 2020 13:16:55 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:33968 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726791AbgHaRQz (ORCPT ); Mon, 31 Aug 2020 13:16:55 -0400 Received: from ibmpc.myhome.or.jp (server.parknet.ne.jp [210.171.168.39]) by mail.parknet.co.jp (Postfix) with ESMTPSA id 5471F1B44DF; Tue, 1 Sep 2020 02:16:54 +0900 (JST) Received: from devron.myhome.or.jp (foobar@devron.myhome.or.jp [192.168.0.3]) by ibmpc.myhome.or.jp (8.15.2/8.15.2/Debian-20) with ESMTPS id 07VHGr4D366255 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 1 Sep 2020 02:16:54 +0900 Received: from devron.myhome.or.jp (foobar@localhost [127.0.0.1]) by devron.myhome.or.jp (8.15.2/8.15.2/Debian-20) with ESMTPS id 07VHGquF3463679 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 1 Sep 2020 02:16:52 +0900 Received: (from hirofumi@localhost) by devron.myhome.or.jp (8.15.2/8.15.2/Submit) id 07VHGqsu3463678; Tue, 1 Sep 2020 02:16:52 +0900 From: OGAWA Hirofumi To: Jens Axboe Cc: Andrew Morton , linux-kernel , fsdevel Subject: Re: [PATCH] fat: Avoid oops when bdi->io_pages==0 References: <87ft85osn6.fsf@mail.parknet.co.jp> <87o8mq6aao.fsf@mail.parknet.co.jp> <4010690f-20ad-f7ba-b595-2e07b0fa2d94@kernel.dk> Date: Tue, 01 Sep 2020 02:16:52 +0900 In-Reply-To: <4010690f-20ad-f7ba-b595-2e07b0fa2d94@kernel.dk> (Jens Axboe's message of "Mon, 31 Aug 2020 10:39:26 -0600") Message-ID: <87h7si68hn.fsf@mail.parknet.co.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe writes: > On 8/31/20 10:37 AM, OGAWA Hirofumi wrote: >> Jens Axboe writes: >> >>> I don't think we should work-around this here. What device is this on? >>> Something like the below may help. >> >> The reported bug is from nvme stack, and the below patch (I submitted >> same patch to you) fixed the reported case though. But I didn't verify >> all possible path, so I'd liked to use safer side. >> >> If block layer can guarantee io_pages!=0 instead, and can apply to >> stable branch (5.8+). It would work too. > > We really should ensure that ->io_pages is always set, imho, instead of > having to work-around it in other spots. I think it is good too. However, the issue would be how to do it for stable branch. If you think that block layer patch is enough and submit to stable (5.8+) branch instead, I'm fine without fatfs patch. (Or removing workaround in fatfs with block layer patch later?) Thanks. -- OGAWA Hirofumi