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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 857A1EB64D7 for ; Wed, 21 Jun 2023 13:27:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230031AbjFUN1l (ORCPT ); Wed, 21 Jun 2023 09:27:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232537AbjFUN1i (ORCPT ); Wed, 21 Jun 2023 09:27:38 -0400 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D74C198D for ; Wed, 21 Jun 2023 06:27:37 -0700 (PDT) Received: by mail-ed1-x52f.google.com with SMTP id 4fb4d7f45d1cf-51bdca52424so767180a12.3 for ; Wed, 21 Jun 2023 06:27:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1687354055; x=1689946055; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=967DLvqkZucBWYuQQC7ZvvfSLYp3m3iK1g1tSsAsumo=; b=b0O4xEb9ZgvBDfAGPENTwzAsvbIfPfAXPyywF1IvFaK7E4iAFAOsT2rVj59NMabncB RYlmwz8b04PN+WED8HMqotadj13ih5Ho5ynizGWLKuMo3klYbYiIEwprcLLKmDi2jA7F qZlO8XOO/CSBDsQeIni4i23JZIDiLXzH+kvPykMnj9g9p8NaGhUBUN2RL0LYRoHvQWi6 MtRaq3EgXDLB3cj+OWIYtHp2TGvwHxrgq/6TStVM3mfuY7Cd0Krb1G7OXkdLvCSel85k NihN7lEvlw0uh3LJTly0wKnOWFudJ7N9hv07OJ+TnIeN4/0VWSoCbSC7OFqUSCu6Nh1E hl/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687354055; x=1689946055; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=967DLvqkZucBWYuQQC7ZvvfSLYp3m3iK1g1tSsAsumo=; b=Mpa3O0aqFkq8vDgAC9qH9niOTjKkX/4QCy3tBBwC85E9mcwhpToOGuvaHjjFD5tzbs XcI5SB5N8vOZJrj2+Wyshw+CS5GXZhYS96+Synds+XqRiCQF3+FiGJjQ5ahvSTYiVNjo K7DpBDzo9Z642PWgZ0H0iUL+Jg/u80OVv2RMAb851HKgluq0mNtGELMJ23xww1md/sKs oxDdsfA4JOUQCKrK0Dufayikca3rk7ChKatO73LzxcsCLe3NwpcYes9SHTh2ySzYjblX DGp+Mgt9ev8EfWRX/xTjxdgAZFHVt5AOWUu0netE4Fyu78GmaFOoFV3fM2DQPhDMiCZH b4rw== X-Gm-Message-State: AC+VfDwrEv4R1cJoBsJeWqj+2LMxtH+2AwVt4u810szDfPyWBhwmWCmL w0M7jKZwpZFAwLnKxnJZPO6Pyg== X-Google-Smtp-Source: ACHHUZ79KyX8mAuWiGAGoUg3ClcvXNY78P0aSXypVeZrGzKCSfDscpmx6uPTblSOyPq98SOb0CnADQ== X-Received: by 2002:a05:6402:6d8:b0:514:9e2c:90c6 with SMTP id n24-20020a05640206d800b005149e2c90c6mr10332144edy.38.1687354055724; Wed, 21 Jun 2023 06:27:35 -0700 (PDT) Received: from [192.168.1.20] ([178.197.219.26]) by smtp.gmail.com with ESMTPSA id w1-20020aa7da41000000b005163c11700csm2621598eds.74.2023.06.21.06.27.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 Jun 2023 06:27:35 -0700 (PDT) Message-ID: Date: Wed, 21 Jun 2023 15:27:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: Regression: NULL pointer dereference after NFS_V4_2_READ_PLUS (commit 7fd461c47) Content-Language: en-US To: Anna Schumaker Cc: Trond Myklebust , Anna Schumaker , linux-nfs , Linux Kernel Mailing List , "regressions@lists.linux.dev" References: <4fe39d77-eb7c-a578-aefa-45b76e2247c2@linaro.org> <86d8e252-975f-5d48-4567-0911d5ef9a44@linaro.org> <85851031-cf43-07d2-8ec7-b40c8c00be91@linaro.org> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/06/2023 14:49, Anna Schumaker wrote: > On Sat, Jun 17, 2023 at 6:09 AM Krzysztof Kozlowski > wrote: >> >> On 15/06/2023 21:38, Anna Schumaker wrote: >>> On Thu, Jun 15, 2023 at 1:16 PM Anna Schumaker wrote: >>>> >>>> On Thu, Jun 15, 2023 at 1:04 PM Anna Schumaker wrote: >>>>> >>>>> On Thu, Jun 15, 2023 at 9:01 AM Anna Schumaker wrote: >>>>>> >>>>>> On Thu, Jun 15, 2023 at 4:55 AM Krzysztof Kozlowski >>>>>> wrote: >>>>>>> >>>>>>> On 15/06/2023 10:52, Krzysztof Kozlowski wrote: >>>>>>>> On 14/06/2023 22:55, Anna Schumaker wrote: >>>>>>>>>>>> Still null ptr (built on 420b2d4 with your patch): >>>>>>>>>>> >>>>>>>>>>> We're through the merge window and at rc1 now, so I can spend more >>>>>>>>>>> time scratching my head over your bug again. We've come up with a >>>>>>>>>>> patch (attached) that adds a bunch of printks to show us what the >>>>>>>>>>> kernel thinks is going on. Do you mind trying it out and letting us >>>>>>>>>>> know what gets printed out? You'll need to make sure >>>>>>>>>>> CONFIG_NFS_V4_2_READ_PLUS is enabled when compiling the kernel. >>>>>>>>>> >>>>>>>>>> The patch does not apply. I tried: v6.4-rc1, v6.4-rc5, next-20230609. >>>>>>>>> >>>>>>>>> Can you try the attached patch on top of my 3-patch series from the >>>>>>>>> other day, and let me know what gets printed out? It adds a bunch of >>>>>>>>> printk()s at strategic points to print out what is going on with the >>>>>>>>> xdr scratch buffer since it's suddenly a bad memory address after >>>>>>>>> working for a bit on your machine. >>>>>>>>> >>>>>>>> >>>>>>>> Here you have entire log - attached (113 kB, I hope goes past mailing >>>>>>>> lists/spam filters). >>>>>>> >>>>>>> As expected this bounced from the mailing lists, but I hope you got it. >>>>>>> If not, let me know. >>>>>> >>>>>> I did still receive it. Thanks! >>>>> >>>>> Can you swap out yesterday's patch with this patch? I've adjusted what >>>>> gets printed out, and added printk()s to xdr_copy_to_scratch(). I'm >>>>> starting to think that the xdr scratch buffer is fine, and that it's >>>>> the other pointer passed to memcpy() in that function that's the >>>>> problem, and the output from this patch will confirm for me. >>>> >>>> Oh, and can you add this one on top of the v2 patch as well? >>> >>> Sorry about the noise today. Can you use this patch instead of the two >>> I attached earlier? I cleaned up the output and cut down on extra >>> output.. >>> >> >> Here you have - attached. > > This is good, thanks! I was finally able to figure out how to hit the > bug using a 32bit x86 VM, so hopefully the next thing you hear from me > is a patch fixing the bug! QEMU also has 32-bit ARM and x86... Best regards, Krzysztof