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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 719C1C433DB for ; Fri, 8 Jan 2021 15:50:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3162A23888 for ; Fri, 8 Jan 2021 15:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727824AbhAHPul (ORCPT ); Fri, 8 Jan 2021 10:50:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727570AbhAHPuk (ORCPT ); Fri, 8 Jan 2021 10:50:40 -0500 Received: from cc-smtpout3.netcologne.de (cc-smtpout3.netcologne.de [IPv6:2001:4dd0:100:1062:25:2:0:3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39754C061380 for ; Fri, 8 Jan 2021 07:50:00 -0800 (PST) Received: from cc-smtpin2.netcologne.de (cc-smtpin2.netcologne.de [89.1.8.202]) by cc-smtpout3.netcologne.de (Postfix) with ESMTP id 5585D12704; Fri, 8 Jan 2021 16:49:58 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by cc-smtpin2.netcologne.de (Postfix) with ESMTP id 5206811E94; Fri, 8 Jan 2021 16:49:58 +0100 (CET) Received: from [213.196.221.66] (helo=cc-smtpin2.netcologne.de) by localhost with ESMTP (eXpurgate 4.11.6) (envelope-from ) id 5ff87f26-024d-7f0000012729-7f000001ce8a-1 for ; Fri, 08 Jan 2021 16:49:58 +0100 Received: from nas2.garloff.de (xdsl-213-196-221-66.nc.de [213.196.221.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by cc-smtpin2.netcologne.de (Postfix) with ESMTPSA; Fri, 8 Jan 2021 16:49:54 +0100 (CET) Received: from [192.168.155.24] (ap4.garloff.de [192.168.155.15]) by nas2.garloff.de (Postfix) with ESMTPSA id A2510B3B13A5; Fri, 8 Jan 2021 16:49:53 +0100 (CET) Subject: Re: NFS 4.2 client support broken on 5.10.5 From: Kurt Garloff To: Trond Myklebust , "NeilB@suse.de" , "Anna.Schumaker@Netapp.com" Cc: "linux-kernel@vger.kernel.org" References: <2f401e0a738b7acb926bd2375012e6384a2cd9b6.camel@hammerspace.com> <927fcf61-7992-1b9f-ae39-c71d96323fbc@garloff.de> Message-ID: <85cd2357-b835-c8b4-ef98-e6b486abbbdc@garloff.de> Date: Fri, 8 Jan 2021 16:49:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <927fcf61-7992-1b9f-ae39-c71d96323fbc@garloff.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Trond, Am 08.01.21 um 15:39 schrieb Kurt Garloff: > Hi Trond, > > On 08/01/2021 12:58, Trond Myklebust wrote: >> On Fri, 2021-01-08 at 12:41 +0100, Kurt Garloff wrote: >>> [...] >>> The kernel tree is on an NFS share, and I run 5.10.5 client kernel >>> against the kernel NFS (4.2) server, running a 5.10.3 kernel. >>> >>> The issue does NOT occur on a 5.10.3 client kernel, but is easily >>> reproducible on 5.10.5. Note that 5.10.5 on a local file system or >>> against an NFSv3 server does not show the issue. >>> >>> Test program that reproduces this on the first pwrite64() is >>> attached. >>> Note that the call to ftruncate() is required to make the problem >>> happen. >>> >>> I could go on bisecting this to a particular patch, but you'll >>> probably be able to see right away what's wrong. >>> >> Hmm... If this is NFSv4.2 do you have READ_PLUS turned on or off in >> .config? It really is not safe to enable READ_PLUS on 5.10 kernels >> since that can cause random memory corruption. > OK, it is turned on in my kernel -- looks like I have not read the > warning in the config option help text carefully enough ... > > I'll test what happens if I switch it off and report back. OK, I compiled a kernel without support for READ_PLUS and the test program magically succeeds. So take my report as input to the developers that work on making READ_PLUS work. Maybe they want to add my little program to their CI suite. Thanks, -- Kurt Garloff , Cologne, Germany