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 ACA8FC28D13 for ; Thu, 25 Aug 2022 05:50:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234467AbiHYFuC (ORCPT ); Thu, 25 Aug 2022 01:50:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230016AbiHYFuB (ORCPT ); Thu, 25 Aug 2022 01:50:01 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0680C15A3B; Wed, 24 Aug 2022 22:50:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AAF3FB826B6; Thu, 25 Aug 2022 05:49:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD9A1C433D6; Thu, 25 Aug 2022 05:49:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661406597; bh=BTJENEVz3AP5yUTbFEI+Q8qyw7FbItjgGfz5IPPlGT4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dimoFRHoNPfm8jJBOl6cE00YTr4K27Ssa/MTZJil/IQ8gyoJ3NG5+vmGdSET+xkfZ D6bT2Qz9gRX40y+5Obukv8orLHoPYtpxx/AFH/6CPIWcJkBfAuMgzS+qAz21zPGomF cpf2ewOap3mW1TJBdlTR7FrOUxg4BBF4WrVdqYCK1VNzFvP5XHK07X/K8Y5J22VD0k I7chndpTlmGw/Xt6Qeb62c6Jrid1+Hwp38nQv3KZNHaeYW7ZdVpnSumc4MU7KImxxS I6KsiCKdfZxiEEgnWY23F9+zrLRCreb683J/vOG23AJ+ltPyIISFsBMRrhpO/h6vdd V2AVvZTGVF1ew== Date: Thu, 25 Aug 2022 08:49:50 +0300 From: Jarkko Sakkinen To: Haitao Huang Cc: Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Reinette Chatre , Paul Menzel , linux-sgx@vger.kernel.org, LKML Subject: Re: WARNING: CPU: 1 PID: 83 at arch/x86/kernel/cpu/sgx/main.c:446 ksgxd+0x1b7/0x1d0 Message-ID: References: <4253695b-85aa-a2fb-fbf6-718db8b6c20c@molgen.mpg.de> <46e3483b-a5ab-2a05-8a28-f9ea87e881c3@intel.com> <04c9d5fa-5861-bbc3-3e2f-e18a73866645@molgen.mpg.de> <63a60042-4a4a-3bc3-5fa1-4495d80cc06c@molgen.mpg.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Wed, Aug 24, 2022 at 09:12:06PM -0500, Haitao Huang wrote: > Hi Paul > > On Tue, 23 Aug 2022 08:48:52 -0500, Paul Menzel > wrote: > > > Dear Dave, > > > > > > Am 20.08.22 um 08:13 schrieb Paul Menzel: > > > > > Am 19.08.22 um 20:28 schrieb Dave Hansen: > > > > On 8/19/22 09:02, Paul Menzel wrote: > > > > > On the Dell XPS 13 9370, Linux 5.18.16 prints the warning below: > > > > > > > > > > ``` > > > > > [ 0.000000] Linux version 5.18.0-4-amd64 > > > > > (debian-kernel@lists.debian.org) (gcc-11 (Debian 11.3.0-5) > > > > > 11.3.0, GNU ld (GNU Binutils for Debian) 2.38.90.20220713) > > > > > #1 SMP PREEMPT_DYNAMIC Debian 5.18.16-1 (2022-08-10) > > > > > [ 0.000000] Command line: > > > > > BOOT_IMAGE=/vmlinuz-5.18.0-4-amd64 > > > > > root=UUID=56f398e0-1e25-4fda-aa9f-611dece4b333 ro quiet > > > > > […] > > > > > [ 0.000000] DMI: Dell Inc. XPS 13 9370/0RMYH9, BIOS > > > > > 1.21.0 07/06/2022 > > > > > […] > > > > > [ 0.235418] sgx: EPC section 0x40200000-0x45f7ffff > > > > > > > Would you be able to send the entire dmesg, along with: > > > The log message are attached to the first message, where I missed > > > to carbon-copy linux-sgx@ [1]. > > > > > > > cat /proc/iomem # (as root) > > > > and > > > > cpuid -1 --raw > > > I am going to provide that next week. (Side note, Intel might have > > > some Dell XPS 9370 test machines in some QA lab.) > > > > Please find both outputs at the end of the file. > > > > Could you also check output of "sudo rdmsr -x 0x3a"? > Also was CONFIG_X86_SGX_KVM set? > > If CONFIG_X86_SGX_KVM is not set and bit 17 (SGX_LC) of the MSR 3A not set, > then I think following sequence during sgx_init is possible: > > sgx_page_cache_init -> sgx_setup_epc_section > ->put all physical EPC pages in sgx_dirty_page_list. > Kick off ksgxd. > Later, sgx_drv_init returns none-zero due to this check: > if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) > return -ENODEV; > sgx_vepc_init also returns none-zero if CONFIG_X86_SGX_KVM was not set. > > And sgx_init will call kthread_stop(ksgxd_tsk): > ret = sgx_drv_init(); > > if (sgx_vepc_init() && ret) > goto err_provision; > ... > err_provision: > misc_deregister(&sgx_dev_provision); > > err_kthread: > kthread_stop(ksgxd_tsk); > > > That triggers __sgx_sanitize_pages return early due to these lines: > /* dirty_page_list is thread-local, no need for a lock: */ > while (!list_empty(dirty_page_list)) { > if (kthread_should_stop()) > return; > > And that would trigger (depends on timing?) the warning in ksgxd due to > non-empty sgx_dirty_page_list > at that moment. You're correct, and it's not a bug but completely legit behaviour. And given that non-empty dirty page list is legit behavior WARN_ON() is not what should be used in here. Fix coming in a bit. BR, Jarkko