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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 339C0C10F00 for ; Sat, 7 Mar 2020 11:53:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 105952070A for ; Sat, 7 Mar 2020 11:53:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726276AbgCGLxJ (ORCPT ); Sat, 7 Mar 2020 06:53:09 -0500 Received: from mga17.intel.com ([192.55.52.151]:37913 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbgCGLxI (ORCPT ); Sat, 7 Mar 2020 06:53:08 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Mar 2020 03:53:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,525,1574150400"; d="scan'208";a="388090759" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.211.93]) ([10.254.211.93]) by orsmga004.jf.intel.com with ESMTP; 07 Mar 2020 03:53:06 -0800 Cc: baolu.lu@linux.intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] iommu/dmar: silence RCU-list debugging warnings To: Qian Cai , jroedel@suse.de References: <1583439302-11393-1-git-send-email-cai@lca.pw> From: Lu Baolu Message-ID: Date: Sat, 7 Mar 2020 19:53:05 +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: <1583439302-11393-1-git-send-email-cai@lca.pw> 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 Hi, On 2020/3/6 4:15, Qian Cai wrote: > Similar to the commit 02d715b4a818 ("iommu/vt-d: Fix RCU list debugging > warnings"), there are several other places that call > list_for_each_entry_rcu() outside of an RCU read side critical section > but with dmar_global_lock held. Silence those false positives as well. > > drivers/iommu/intel-iommu.c:4288 RCU-list traversed in non-reader section!! > 1 lock held by swapper/0/1: > #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1ad/0xb97 > > drivers/iommu/dmar.c:366 RCU-list traversed in non-reader section!! > 1 lock held by swapper/0/1: > #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x125/0xb97 > > drivers/iommu/intel-iommu.c:5057 RCU-list traversed in non-reader section!! > 1 lock held by swapper/0/1: > #0: ffffffffa71892c8 (dmar_global_lock){++++}, at: intel_iommu_init+0x61a/0xb13 > > Signed-off-by: Qian Cai Thanks for the fix. Acked-by: Lu Baolu Best regards, baolu > --- > drivers/iommu/dmar.c | 3 ++- > include/linux/dmar.h | 6 ++++-- > 2 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c > index 071bb42bbbc5..7b16c4db40b4 100644 > --- a/drivers/iommu/dmar.c > +++ b/drivers/iommu/dmar.c > @@ -363,7 +363,8 @@ static int dmar_pci_bus_notifier(struct notifier_block *nb, > { > struct dmar_drhd_unit *dmaru; > > - list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list) > + list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list, > + dmar_rcu_check()) > if (dmaru->segment == drhd->segment && > dmaru->reg_base_addr == drhd->address) > return dmaru; > diff --git a/include/linux/dmar.h b/include/linux/dmar.h > index 712be8bc6a7c..d7bf029df737 100644 > --- a/include/linux/dmar.h > +++ b/include/linux/dmar.h > @@ -74,11 +74,13 @@ struct dmar_pci_notify_info { > dmar_rcu_check()) > > #define for_each_active_drhd_unit(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 (drhd->ignored) {} else > > #define for_each_active_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, drhd->ignored) {} else > > #define for_each_iommu(i, drhd) \ >