From patchwork Tue Mar 17 10:55:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 229320 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 E6489C2BB1D for ; Tue, 17 Mar 2020 11:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB1B02073E for ; Tue, 17 Mar 2020 11:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584443100; bh=bqm0Y8tO/dFhUHmulnxoCqYXix/ToV0sUlKmOmGJm5M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Zom1wKbdCJ4vOxp+j+Re7qAX2kDTEaWwlHLr96nQ71dSwIkJlszvUDGoukkMYm3iR 1ElA/o/xJ9l9+3s7qtnHt94jYi7lOoKiTo7pQTpQIoJP5n945GMhmllCwdPNNJAXBy j3H5MWtrS49j3BOGtpEmZ+if1dOvnpZ3Pn8VlTW0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728338AbgCQLE7 (ORCPT ); Tue, 17 Mar 2020 07:04:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:45538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728344AbgCQLE5 (ORCPT ); Tue, 17 Mar 2020 07:04:57 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EB88720771; Tue, 17 Mar 2020 11:04:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584443097; bh=bqm0Y8tO/dFhUHmulnxoCqYXix/ToV0sUlKmOmGJm5M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Aj4f8b3xiFeDE/2s5XGsJ/5b4ReGhfjfcv1jrgoY4F7R0lDMQEXONDCDjuBWgSgLl DivMX+k0+uwSX1u8heg64nkPY5niWqt1izMvpTSjMBWCnBmblgL+ACPN9CTT4rCjKx txjfV2bqm2rZ6n/I4VmRHV0EbPsHJNWs2ZIrxgUk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhuparna Bhowmik , Amol Grover , Lu Baolu , Joerg Roedel Subject: [PATCH 5.4 095/123] iommu/vt-d: Fix RCU list debugging warnings Date: Tue, 17 Mar 2020 11:55:22 +0100 Message-Id: <20200317103317.500427525@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200317103307.343627747@linuxfoundation.org> References: <20200317103307.343627747@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Amol Grover commit 02d715b4a8182f4887d82df82a7b83aced647760 upstream. 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 Cc: stable@vger.kernel.org Acked-by: Lu Baolu Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- include/linux/dmar.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -69,8 +69,9 @@ struct dmar_pci_notify_info { extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; -#define for_each_drhd_unit(drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) +#define for_each_drhd_unit(drhd) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) #define for_each_active_drhd_unit(drhd) \ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ @@ -81,7 +82,8 @@ extern struct list_head dmar_drhd_units; if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, 0) {} else static inline bool dmar_rcu_check(void)