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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 6C6E4C4332D for ; Thu, 19 Mar 2020 14:16:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4BD032080C for ; Thu, 19 Mar 2020 14:16:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727518AbgCSOQX (ORCPT ); Thu, 19 Mar 2020 10:16:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:45660 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726926AbgCSOQW (ORCPT ); Thu, 19 Mar 2020 10:16:22 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 4919DAE6F; Thu, 19 Mar 2020 14:16:21 +0000 (UTC) Date: Thu, 19 Mar 2020 15:16:19 +0100 From: Joerg Roedel To: Lu Baolu Cc: Qian Cai , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu/vt-d: silence a RCU-list debugging warning Message-ID: <20200319141619.GC611@suse.de> References: <20200317150326.1659-1-cai@lca.pw> <36b9e69b-ee3f-c17d-1788-64448ce8bc14@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <36b9e69b-ee3f-c17d-1788-64448ce8bc14@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 18, 2020 at 01:27:53PM +0800, Lu Baolu wrote: > On 2020/3/17 23:03, Qian Cai wrote: > > 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 > > How about changing the commit subject to > "iommu/vt-d: Silence RCU-list debugging warning in dmar_find_atsr()"? > > Acked-by: Lu Baolu Fixed up the subject and applied it, thanks.