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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 A59E9C38A29 for ; Sat, 18 Apr 2020 14:44:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7BA2422202 for ; Sat, 18 Apr 2020 14:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587221074; bh=7RfogpTkIK5I7EqQCPrEvs26vCxY4C5QUahlumpM6cA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dztukfP20lt8ub0UcywNi/b+HN9JzWf/5ecWHAw88RmHPTlgDZ6uX+NGUH8ai0C60 NjvDvwqIL0s8c4g5RyS9TwJiEN60eMJDjK5RTWJgSF8Pi9NqsWyTXKXCEilgyEv2Ng M4/9+RxvcZMEw/pxLd9v05N6Em/U40KQ+is+i8+g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728835AbgDROod (ORCPT ); Sat, 18 Apr 2020 10:44:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:56118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728803AbgDROo1 (ORCPT ); Sat, 18 Apr 2020 10:44:27 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DB51421D79; Sat, 18 Apr 2020 14:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587221066; bh=7RfogpTkIK5I7EqQCPrEvs26vCxY4C5QUahlumpM6cA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jpIMx1EawXOgU/YtA7SZN+LshWQqlPJxsr/x3rlgInA4nJSZ1YRIWJ/KhmUqaXxoZ +hjDrmkImy+5qWuPeZa29DACGX7GWkbckMee6pYtVv/5/bWc/MHO4Y7dHLgUgNoZv6 U1Urhfi4T44XslKImVTk4J/UJNodrKMMqxKSC8uA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Qian Cai , Lu Baolu , Joerg Roedel , Sasha Levin , iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 4.9 16/23] iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr() Date: Sat, 18 Apr 2020 10:43:58 -0400 Message-Id: <20200418144405.10565-16-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200418144405.10565-1-sashal@kernel.org> References: <20200418144405.10565-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 593a4bfcba428..31691d853a3cd 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4300,7 +4300,8 @@ 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