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 E5C85C433F5 for ; Mon, 28 Mar 2022 06:51:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238593AbiC1GxJ (ORCPT ); Mon, 28 Mar 2022 02:53:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238596AbiC1GxG (ORCPT ); Mon, 28 Mar 2022 02:53:06 -0400 Received: from mx1.molgen.mpg.de (mx3.molgen.mpg.de [141.14.17.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D598552B2E; Sun, 27 Mar 2022 23:51:17 -0700 (PDT) Received: from [192.168.0.3] (ip5f5aef5a.dynamic.kabel-deutschland.de [95.90.239.90]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) (Authenticated sender: pmenzel) by mx.molgen.mpg.de (Postfix) with ESMTPSA id CD20D61EA1928; Mon, 28 Mar 2022 08:51:15 +0200 (CEST) Message-ID: <4a49a98a-d958-8e48-10eb-24bb220e24ed@molgen.mpg.de> Date: Mon, 28 Mar 2022 08:51:15 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: BUG: Bad page state in process systemd-udevd (was: [PATCH v9 bpf-next 1/9] x86/Kconfig: select HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP) Content-Language: en-US To: Song Liu , Rick P Edgecombe Cc: Song Liu , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Kernel-team@fb.com, Peter Zijlstra , x86@kernel.org, iii@linux.ibm.com, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , regressions@lists.linux.dev References: <20220204185742.271030-1-song@kernel.org> <20220204185742.271030-2-song@kernel.org> <14444103-d51b-0fb3-ee63-c3f182f0b546@molgen.mpg.de> <7edcd673-decf-7b4e-1f6e-f2e0e26f757a@molgen.mpg.de> <7F597B8E-72B3-402B-BD46-4C7F13A5D7BD@fb.com> From: Paul Menzel In-Reply-To: <7F597B8E-72B3-402B-BD46-4C7F13A5D7BD@fb.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Dear Song, Am 28.03.22 um 08:37 schrieb Song Liu: > Thanks Paul for highlighting the issue. Thank you for getting back to me so quickly. > + Rick, who highlighted some potential issues with this. (also attached > the stack trace). I already had added him, but forgot to document it in the message. Sorry for that. >> On Mar 27, 2022, at 3:36 AM, Paul Menzel wrote: >> Am 26.03.22 um 19:46 schrieb Paul Menzel: >>> #regzbot introduced: fac54e2bfb5be2b0bbf115fe80d45f59fd773048 >>> #regzbot title: BUG: Bad page state in process systemd-udevd >> >>> Am 04.02.22 um 19:57 schrieb Song Liu: >>>> From: Song Liu >>>> >>>> This enables module_alloc() to allocate huge page for 2MB+ requests. >>>> To check the difference of this change, we need enable config >>>> CONFIG_PTDUMP_DEBUGFS, and call module_alloc(2MB). Before the change, >>>> /sys/kernel/debug/page_tables/kernel shows pte for this map. With the >>>> change, /sys/kernel/debug/page_tables/ show pmd for thie map. >>>> >>>> Signed-off-by: Song Liu >>>> --- >>>> arch/x86/Kconfig | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>>> index 6fddb63271d9..e0e0d00cf103 100644 >>>> --- a/arch/x86/Kconfig >>>> +++ b/arch/x86/Kconfig >>>> @@ -159,6 +159,7 @@ config X86 >>>> select HAVE_ALIGNED_STRUCT_PAGE if SLUB >>>> select HAVE_ARCH_AUDITSYSCALL >>>> select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE >>>> + select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP >>>> select HAVE_ARCH_JUMP_LABEL >>>> select HAVE_ARCH_JUMP_LABEL_RELATIVE >>>> select HAVE_ARCH_KASAN if X86_64 >>> Testing Linus’ current master branch, Linux logs critical messages like below: >>> BUG: Bad page state in process systemd-udevd pfn:102e03 >>> I bisected to your commit fac54e2bfb5 (x86/Kconfig: select >>> HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP). >> >> Sorry, I forget to mention, that this is a 32-bit (i686) userspace, >> but a 64-bit Linux kernel, so it might be the same issue as >> mentioned in commit eed1fcee556f (x86: Disable >> HAVE_ARCH_HUGE_VMALLOC on 32-bit x86), but didn’t fix the issue for >> 64-bit Linux kernel and 32-bit userspace. > > I will look more into this tomorrow. To clarify, what is the 32-bit > user space that triggers this? Is it systemd-udevd? Is the systemd > also i686? Yes, everything – also systemd – is i686. You can build a 32-bit VM image with grml-debootstrap [1]: sudo DEBOOTSTRAP=mmdebstrap ~/src/grml-debootstrap/grml-debootstrap --vm --vmfile --vmsize 3G --target /dev/shm/debian-32.img -r sid --arch i686 --filesystem ext4 Then run that with QEMU, but pass the 64-bit Linux kernel to QEMU directly with the switches `-kernel` and `-append`, or install the amd64 Linux kernel into the Debian VM image or the package created with `make bindeb-pkg` with `dpkg -i …`. Kind regards, Paul [1]: https://github.com/grml/grml-debootstrap/