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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 94EEAC433E1 for ; Sat, 25 Jul 2020 10:38:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DD8D206C1 for ; Sat, 25 Jul 2020 10:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595673536; bh=ugfaCdOmsh+SINTvVJocI7HdQFsBVqnfcacYCEu4+UQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=wWQxtLshofvPtK18geBpg7I6njb0wQKVYuU+fzu8beH4u0jiocw3SAz7PIw1wWOVO 1PnNjtUdb4E9CRFkNzydRLPkmX5xl52iG9+sLqrXhqOx0Lz5nvzGZXSRrV8nypASIL XZLcQ+w/JkTajY17ZNeFotkp2jP6/+KzFi3eyIDA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726994AbgGYKiz (ORCPT ); Sat, 25 Jul 2020 06:38:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726694AbgGYKiy (ORCPT ); Sat, 25 Jul 2020 06:38:54 -0400 Received: from mail-ed1-x542.google.com (mail-ed1-x542.google.com [IPv6:2a00:1450:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54487C0619D3 for ; Sat, 25 Jul 2020 03:38:54 -0700 (PDT) Received: by mail-ed1-x542.google.com with SMTP id a8so8733941edy.1 for ; Sat, 25 Jul 2020 03:38:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Abyy2Er/XsCBrdFLrMSrl7iTqnBYYPdm4277heekMEY=; b=EF7EvHSzrz8fBp+uinEBiF5rMEKU+b/MqvCBYhOvAzK9laJbUZ4Qo5BwKXbrWjHP4f miaAF7u1TvS5MDKzlEf9iRr4RkDEB5PpNCO4xrMmJ19Z9P4QIZ52DHh+O5O2/TqtENnA e0J77O5ZezxnvGPacwQHlqOB2Vo9hLTGpk6SSVZ1WO7O3qgHQ5AfIqa/LUKQWmEWz8V6 9CFiKJVf6AnGZcMhHipH3izJlfiBFTTbCo8LgXx49a4l41WgpoANGnsGjn91euAx5Cdd V90L8DOVJs6q0woZr+HpwB5ybnObW24shG/xQEcx6Zwgi+lBnLdG0499Nv8bjWNNnvlc Zqdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=Abyy2Er/XsCBrdFLrMSrl7iTqnBYYPdm4277heekMEY=; b=C6wOQ66PfcKKPKKtpCpwFYhRNCpSBL15HhHWr0ZM1qi4qY0E2YelqitURS1kzmlJP9 UEqVsWkVi6eX3x8hWtNAWzQphN9lyCvGDKLfHBYttszaCqD1btv4fakM9f+9i6qzaXck eme2nGj1CMsLPdEZNUWEGcyR9YK3rz5KmXLJlKdfPyduttxDCFRXAnAOkr6MZU8qojJT YIP6doQmBGv9NocsI9DLfwn0CJOPKs+n8NHZ9kwXybeBJCJk0fe89VVIDuIFsMTpaGIn dE7zLcK2dffIfS876DMckS/OtZT2noT2K8q9om8SUVHFdMC8gnrTh+3yj/7MIb1Q5Znk ujOQ== X-Gm-Message-State: AOAM532SlYPpK/mqkmGil2FJqC2YwhKD9JmcKDZ8X4Qwbs2trQ/ZJeK5 cYm3eJTWEYjQO+3IRcbKBJQ= X-Google-Smtp-Source: ABdhPJz5Y0QHB+pK2pUF/HVuG2dJPXyVFpIL6Z2EnqoCsfk00LhMv+FxGuBeVbytWZx8S4mBMsf/QA== X-Received: by 2002:a05:6402:1841:: with SMTP id v1mr12914069edy.198.1595673533056; Sat, 25 Jul 2020 03:38:53 -0700 (PDT) Received: from gmail.com (54033286.catv.pool.telekom.hu. [84.3.50.134]) by smtp.gmail.com with ESMTPSA id mj22sm2599772ejb.118.2020.07.25.03.38.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 25 Jul 2020 03:38:52 -0700 (PDT) Date: Sat, 25 Jul 2020 12:38:50 +0200 From: Ingo Molnar To: Joerg Roedel Cc: Thomas Gleixner , x86@kernel.org, Peter Zijlstra , Arnaldo Carvalho de Melo , Andy Lutomirski , Dave Hansen , linux-kernel@vger.kernel.org Subject: Re: Regression on todays tip/master (commit 16f70beccf43) Message-ID: <20200725103850.GA823877@gmail.com> References: <20200723133743.GA30716@8bytes.org> <871rl2xpar.fsf@nanos.tec.linutronix.de> <20200723145219.GP27672@8bytes.org> <20200724132802.GA640628@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200724132802.GA640628@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > * Joerg Roedel wrote: > > > On Thu, Jul 23, 2020 at 04:46:04PM +0200, Thomas Gleixner wrote: > > > Joerg Roedel writes: > > > > while testing the SEV-ES patches on todays tip/master I triggered the BUG > > > > below: > > > > > > > > [ 137.629660] ------------[ cut here ]------------ > > > > [ 137.630769] kernel BUG at kernel/signal.c:1917! > > > > [ 137.631796] invalid opcode: 0000 [#1] SMP NOPTI > > > > [ 137.632822] CPU: 3 PID: 28596 Comm: test_syscall_vd Not tainted 5.8.0-rc6-tip+ #3 > > > > [ 137.634495] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 > > > > [ 137.636236] RIP: 0010:do_notify_parent+0x25c/0x290 > > > > The guest had 4 VCPUs and ran 4 instances of the in-kernel x86-selftests > > > > in a loop, together with 'perf top -e cycles:k'. As you can see in the > > > > time-stamps, the issue triggered pretty quickly. > > > > > > > > Please let me know if you need more information or testing from my side. > > > > > > Any chance to bisect this? > > > > Yes, will try. I am currently testing plain -rc6, it seems to be fine. > > Bisecting is next. > > Given that you are perf stress-testing the box, some recent perf > commit would be the primary suspect - before doing a full bisect you > might want to try current perf/core (2ac5413e5edc) and its upstream > base: v5.8-rc3, to narrow it down. > > But in principle any other commit could be the cause as well, the > assert suggests memory corruption - I don't think we changed anything > in the signal code. On a second thought, I think this recent bug might have been the culprit: d136122f5845: ("sched: Fix race against ptrace_freeze_trace()") Fixed in tip:sched/urgent - this is why it went away in your testing perhaps? I'm sending this fix to Linus today. Thanks, Ingo