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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 1FA2AC31E44 for ; Wed, 12 Jun 2019 00:38:49 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F3648208C2 for ; Wed, 12 Jun 2019 00:38:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3648208C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 9A0CC148E; Wed, 12 Jun 2019 00:38:21 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id B1D22146E for ; Wed, 12 Jun 2019 00:36:17 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 466AE775 for ; Wed, 12 Jun 2019 00:36:17 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Jun 2019 17:36:17 -0700 X-ExtLoop1: 1 Received: from allen-box.sh.intel.com ([10.239.159.136]) by orsmga001.jf.intel.com with ESMTP; 11 Jun 2019 17:36:15 -0700 From: Lu Baolu To: Joerg Roedel , David Woodhouse Subject: [PATCH v2 5/7] iommu/vt-d: Fix suspicious RCU usage in probe_acpi_namespace_devices() Date: Wed, 12 Jun 2019 08:28:49 +0800 Message-Id: <20190612002851.17103-6-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190612002851.17103-1-baolu.lu@linux.intel.com> References: <20190612002851.17103-1-baolu.lu@linux.intel.com> Cc: kevin.tian@intel.com, ashok.raj@intel.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, cai@lca.pw, jacob.jun.pan@intel.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org The drhd and device scope list should be iterated with the iommu global lock held. Otherwise, a suspicious RCU usage message will be displayed. [ 3.695886] ============================= [ 3.695917] WARNING: suspicious RCU usage [ 3.695950] 5.2.0-rc2+ #2467 Not tainted [ 3.695981] ----------------------------- [ 3.696014] drivers/iommu/intel-iommu.c:4569 suspicious rcu_dereference_check() usage! [ 3.696069] other info that might help us debug this: [ 3.696126] rcu_scheduler_active = 2, debug_locks = 1 [ 3.696173] no locks held by swapper/0/1. [ 3.696204] stack backtrace: [ 3.696241] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc2+ #2467 [ 3.696370] Call Trace: [ 3.696404] dump_stack+0x85/0xcb [ 3.696441] intel_iommu_init+0x128c/0x13ce [ 3.696478] ? kmem_cache_free+0x16b/0x2c0 [ 3.696516] ? __fput+0x14b/0x270 [ 3.696550] ? __call_rcu+0xb7/0x300 [ 3.696583] ? get_max_files+0x10/0x10 [ 3.696631] ? set_debug_rodata+0x11/0x11 [ 3.696668] ? e820__memblock_setup+0x60/0x60 [ 3.696704] ? pci_iommu_init+0x16/0x3f [ 3.696737] ? set_debug_rodata+0x11/0x11 [ 3.696770] pci_iommu_init+0x16/0x3f [ 3.696805] do_one_initcall+0x5d/0x2e4 [ 3.696844] ? set_debug_rodata+0x11/0x11 [ 3.696880] ? rcu_read_lock_sched_held+0x6b/0x80 [ 3.696924] kernel_init_freeable+0x1f0/0x27c [ 3.696961] ? rest_init+0x260/0x260 [ 3.696997] kernel_init+0xa/0x110 [ 3.697028] ret_from_fork+0x3a/0x50 Fixes: fa212a97f3a36 ("iommu/vt-d: Probe DMA-capable ACPI name space devices") Signed-off-by: Lu Baolu --- drivers/iommu/intel-iommu.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 19c4c387a3f6..84e650c6a46d 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4793,8 +4793,10 @@ int __init intel_iommu_init(void) cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL, intel_iommu_cpu_dead); + down_read(&dmar_global_lock); if (probe_acpi_namespace_devices()) pr_warn("ACPI name space devices didn't probe correctly\n"); + up_read(&dmar_global_lock); /* Finally, we enable the DMA remapping hardware. */ for_each_iommu(iommu, drhd) { -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu