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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 B068AC55186 for ; Wed, 22 Apr 2020 10:30:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7FC052073A for ; Wed, 22 Apr 2020 10:30:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587551425; bh=fGz7a64lWYFN33TvpNVh9lbizXvizlbW6RS4o/D26oI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PACs7SYv7uMNcY59mPu+jd+h898Lu7RrDN94DJwmw/HfSZogaTlYAP9iFQZiaQ5G9 itPt6Js9yLnynKwp9zZREztssn4+9GfEkeqilZPZa3JQV1W6lpTHf1J5S8ZWF05W3I s9UruRiMh7kDehnxdvIs5qv3ssFec3Q4n9y9i1EM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731045AbgDVKaW (ORCPT ); Wed, 22 Apr 2020 06:30:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:35250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730722AbgDVK0X (ORCPT ); Wed, 22 Apr 2020 06:26:23 -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 491F42075A; Wed, 22 Apr 2020 10:26:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587551182; bh=fGz7a64lWYFN33TvpNVh9lbizXvizlbW6RS4o/D26oI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fcj9RF3Yuk1qWYCkIYRZa84LxB2oIArh8FxoYaloLMXuPm9JZ8bUB8WdTBuDnqB5S h5aU7slLfxEnQkMBa40gNkC8flCJAwKtPDr3KDK9pUwks3gnVgDAaazpL0XRzaX1gt yC88SNi0UBIkNUBNM+8S/pHGK9EBWNCLHCHFr9Cc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qian Cai , Lu Baolu , Joerg Roedel , Sasha Levin Subject: [PATCH 5.6 134/166] iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr() Date: Wed, 22 Apr 2020 11:57:41 +0200 Message-Id: <20200422095103.005670022@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095047.669225321@linuxfoundation.org> References: <20200422095047.669225321@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qian Cai [ Upstream commit c6f4ebdeba4cff590594df931ff1ee610c426431 ] dmar_find_atsr() calls list_for_each_entry_rcu() outside of an RCU read side critical section but with dmar_global_lock held. Silence this false positive. drivers/iommu/intel-iommu.c:4504 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff9755bee8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1a6/0xe19 Call Trace: dump_stack+0xa4/0xfe lockdep_rcu_suspicious+0xeb/0xf5 dmar_find_atsr+0x1ab/0x1c0 dmar_parse_one_atsr+0x64/0x220 dmar_walk_remapping_entries+0x130/0x380 dmar_table_init+0x166/0x243 intel_iommu_init+0x1ab/0xe19 pci_iommu_init+0x1a/0x44 do_one_initcall+0xae/0x4d0 kernel_init_freeable+0x412/0x4c5 kernel_init+0x19/0x193 Signed-off-by: Qian Cai Acked-by: Lu Baolu Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 4be5494786918..ef0a5246700e5 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4501,7 +4501,8 @@ static struct dmar_atsr_unit *dmar_find_atsr(struct acpi_dmar_atsr *atsr) struct dmar_atsr_unit *atsru; struct acpi_dmar_atsr *tmp; - list_for_each_entry_rcu(atsru, &dmar_atsr_units, list) { + list_for_each_entry_rcu(atsru, &dmar_atsr_units, list, + dmar_rcu_check()) { tmp = (struct acpi_dmar_atsr *)atsru->hdr; if (atsr->segment != tmp->segment) continue; -- 2.20.1