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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 3102FC35670 for ; Sun, 23 Feb 2020 23:37:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0426C206E0 for ; Sun, 23 Feb 2020 23:37:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727166AbgBWXhw (ORCPT ); Sun, 23 Feb 2020 18:37:52 -0500 Received: from mga05.intel.com ([192.55.52.43]:65515 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726534AbgBWXhw (ORCPT ); Sun, 23 Feb 2020 18:37:52 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Feb 2020 15:34:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,477,1574150400"; d="scan'208";a="349801062" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.212.230]) ([10.254.212.230]) by fmsmga001.fm.intel.com with ESMTP; 23 Feb 2020 15:34:48 -0800 Cc: baolu.lu@linux.intel.com, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, Joel Fernandes , Madhuparna Bhowmik , "Paul E . McKenney" Subject: Re: [PATCH RESEND] iommu: dmar: Fix RCU list debugging warnings To: Amol Grover , Allison Randal , Greg Kroah-Hartman , Andrew Morton , Thomas Gleixner , Qian Cai , Deepa Dinamani , Joerg Roedel References: <20200223165538.29870-1-frextrite@gmail.com> From: Lu Baolu Message-ID: Date: Mon, 24 Feb 2020 07:34:27 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200223165538.29870-1-frextrite@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/2/24 0:55, Amol Grover wrote: > dmar_drhd_units is traversed using list_for_each_entry_rcu() > outside of an RCU read side critical section but under the > protection of dmar_global_lock. Hence add corresponding lockdep > expression to silence the following false-positive warnings: > > [ 1.603975] ============================= > [ 1.603976] WARNING: suspicious RCU usage > [ 1.603977] 5.5.4-stable #17 Not tainted > [ 1.603978] ----------------------------- > [ 1.603980] drivers/iommu/intel-iommu.c:4769 RCU-list traversed in non-reader section!! > > [ 1.603869] ============================= > [ 1.603870] WARNING: suspicious RCU usage > [ 1.603872] 5.5.4-stable #17 Not tainted > [ 1.603874] ----------------------------- > [ 1.603875] drivers/iommu/dmar.c:293 RCU-list traversed in non-reader section!! > > Tested-by: Madhuparna Bhowmik > Signed-off-by: Amol Grover Thanks for the fix. Cc: stable@vger.kernel.org Acked-by: Lu Baolu Best regards, baolu