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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 9FED4C433E0 for ; Fri, 12 Jun 2020 03:30:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C33020878 for ; Fri, 12 Jun 2020 03:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591932634; bh=LkU0aSGFes8SdfS/64Est12NefN8zfPhEnQa83oS7lk=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=oqthus2Yo0abkCuWDgtPkG+08jaV7FsxUSFJGhV8/2efO0S5X90IONYcLq0mlJMdy 64f7D/a0iQ9EsC4VIMuFgeXUnHK24LW+kyJxHtF2cPha0R7vnHHmueADHG69CwJYlX /1Z1qumUomB4lruADjv5UivwMhI6X9EFj9kdYZRs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726520AbgFLDac (ORCPT ); Thu, 11 Jun 2020 23:30:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:38412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726327AbgFLDac (ORCPT ); Thu, 11 Jun 2020 23:30:32 -0400 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5AF5220878 for ; Fri, 12 Jun 2020 03:30:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591932631; bh=LkU0aSGFes8SdfS/64Est12NefN8zfPhEnQa83oS7lk=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=QCBckqUf+QlzzWculQ/xI3jdcyylkJKJn4Fp55LrgpX39KOdF+ukDyMcQj9+qrw0z dh9JMfWZl2SjIQh+DooIrQyF6bOYFr73y8H7BRbDS0FKvF0BlQq5GgRA+AGemsQW0s 4ioSm9pWEg7Ydcrwych4IgXePuM4sMCfvggWJO1M= Received: by mail-wm1-f48.google.com with SMTP id y20so6923475wmi.2 for ; Thu, 11 Jun 2020 20:30:31 -0700 (PDT) X-Gm-Message-State: AOAM533TU6yJ3ll0FnxVhoAe7p7toqNR33nLgTx5pFkw0Vzy5eQN403U iAufVcWW2umrzclsT62Xipy2Z9eCUPsECBwPZr2IDg== X-Google-Smtp-Source: ABdhPJzsX6f0tjw6qMwpnhb4setFA9eVXwUcrdWDzQL+Oe/A7dX6gpa/YF+7fLsJW7ydpKDV/WohRXRprUqgTb8xibw= X-Received: by 2002:a05:600c:22da:: with SMTP id 26mr11004447wmg.176.1591932629995; Thu, 11 Jun 2020 20:30:29 -0700 (PDT) MIME-Version: 1.0 References: <20200611192518.GA2483@worktop.programming.kicks-ass.net> In-Reply-To: From: Andy Lutomirski Date: Thu, 11 Jun 2020 20:30:18 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Perf: WARNING: arch/x86/entry/common.c:624 idtentry_exit_cond_rcu+0x92/0xc0 To: Andy Lutomirski Cc: Peter Zijlstra , Naresh Kamboju , open list , X86 ML , cj.chengjian@huawei.com, Arnaldo Carvalho de Melo , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Thomas Gleixner , Minchan Kim , Andrew Morton , Michel Lespinasse , lkft-triage@lists.linaro.org, Dave Hansen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 11, 2020 at 4:22 PM Andy Lutomirski wrote: > > On Thu, Jun 11, 2020 at 12:25 PM Peter Zijlstra wrote: > > > > On Thu, Jun 11, 2020 at 12:10:50PM -0700, Andy Lutomirski wrote: > > > On Thu, Jun 11, 2020 at 11:56 AM Naresh Kamboju > > > wrote: > > > > > > > > While running perf test and selftest x86 single_step_syscall_32 on > > > > i386 kernel linux > > > > next 5.7.0-next-20200610 kernel warning noticed. > > > > > > > > steps to reproduce: > > > > -------------------------- > > > > perf test > > > > and > > > > cd /opt/kselftests/default-in-kernel/x86 > > > > ./single_step_syscall_32 > > > > > > > > perf warning log: > > > > ---------------------- > > > > [ 57.260865] ------------[ cut here ]------------ > > > > [ 57.266576] IRQs not disabled as expected > > > > [ 57.270583] WARNING: CPU: 1 PID: 500 at > > > > /usr/src/kernel/arch/x86/entry/common.c:624 > > > > idtentry_exit_cond_rcu+0x92/0xc0 > > > > [ 57.281092] Modules linked in: x86_pkg_temp_thermal fuse > > > > [ 57.286406] CPU: 1 PID: 500 Comm: perf Not tainted 5.7.0-next-20200610 #1 > > > > [ 57.293190] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.2 05/23/2018 > > > > [ 57.300577] EIP: idtentry_exit_cond_rcu+0x92/0xc0 > > > > [ 57.305280] Code: 8b 89 d8 05 00 00 85 c9 74 ae 80 3d b1 64 2c d4 > > > > 00 75 a5 68 94 2d fb d3 89 55 f8 89 45 fc c6 05 b1 64 2c d4 01 e8 8e > > > > f5 2b ff <0f> 0b 58 8b 55 f8 8b 45 fc eb 83 8d 76 00 e8 5b fd ff ff c9 > > > > c3 89 > > > > [ 57.324017] EAX: 0000001d EBX: 0d00022a ECX: 00000027 EDX: f5b9e14c > > > > [ 57.330274] ESI: f2a2ffb4 EDI: ffff0ff4 EBP: f2a2ff8c ESP: f2a2ff80 > > > > [ 57.336531] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010096 > > > > [ 57.343345] CR0: 80050033 CR2: 08700a58 CR3: 14ad7000 CR4: 003406d0 > > > > [ 57.349608] DR0: 080dfb80 DR1: 080dfc00 DR2: 08700a58 DR3: 00000000 > > > > [ 57.355866] DR6: fffe0ff0 DR7: 0d00062a > > > > [ 57.359697] Call Trace: > > > > [ 57.362143] exc_debug+0x84/0x1b0 > > > > [ 57.365487] ? exc_int3+0x1d0/0x1d0 > > > > [ 57.368981] handle_exception+0x145/0x145 > > > > [ 57.372991] EIP: 0x80dfbcd > > > > [ 57.375694] Code: Bad RIP value. > > > > [ 57.378918] EAX: 00000000 EBX: 00000005 ECX: 00002400 EDX: 00000000 > > > > [ 57.385175] ESI: 00000003 EDI: 00000004 EBP: bfd59798 ESP: bfd59770 > > > > [ 57.391431] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000246 > > > > [ 57.398215] irq event stamp: 1896 > > > > > > A regrettable property of the current entry code structure is that we > > > lose any real indication of the vector. Presumably this is #DB, hence > > > exc_debug. I don't know what perf has to do with it. > > > > > > I'll bang on this after lunch if no one beats me to it. > > > > Puzzling, CR3 seems to suggest this is !user_mode(), but either way #DB > > has either idtentry_enter_user() or nmi_enter(). > > > > I just got this splat on 32-bit while running my perf abuser here: > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/misc-tests.git/tree/perf_lots_of_nmi.c > > [ 21.874114] traps: PANIC: double fault, error_code: 0x0 Two bugs here. 1. We had an issue with WARN. Patch sent. 2. idtentry.h has, for x86_32: # define DEFINE_IDTENTRY_IST DEFINE_IDTENTRY This is nonsense. It's getting late over here and I'd rather focus on the more interesting RCU issue, so that's all from me today. --Andy