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=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 5F3B0C10F00 for ; Sat, 7 Mar 2020 11:52:35 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 24EEE2070A for ; Sat, 7 Mar 2020 11:52:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24EEE2070A 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 localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id E9007203B1; Sat, 7 Mar 2020 11:52:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SROvzx7jBfCR; Sat, 7 Mar 2020 11:52:33 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 2A1292034F; Sat, 7 Mar 2020 11:52:33 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 1E882C08A0; Sat, 7 Mar 2020 11:52:33 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id B76D4C013E for ; Sat, 7 Mar 2020 11:52:31 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id A216986CDD for ; Sat, 7 Mar 2020 11:52:31 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bx4JL8xmyHjh for ; Sat, 7 Mar 2020 11:52:31 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 022FB86CC9 for ; Sat, 7 Mar 2020 11:52:30 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Mar 2020 03:52:30 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,525,1574150400"; d="scan'208";a="388090627" 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 03:52:28 -0800 Subject: Re: [PATCH] iommu/vt-d: fix RCU-list bugs in intel_iommu_init To: Qian Cai , jroedel@suse.de References: <1583438446-9959-1-git-send-email-cai@lca.pw> From: Lu Baolu Message-ID: <4d2297b6-f719-68d5-973b-df9405caa7a0@linux.intel.com> Date: Sat, 7 Mar 2020 19:52:27 +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: <1583438446-9959-1-git-send-email-cai@lca.pw> Content-Language: en-US Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi, On 2020/3/6 4:00, Qian Cai wrote: > There are several places traverse RCU-list without holding any lock in > intel_iommu_init(). Fix them by acquiring dmar_global_lock. > > WARNING: suspicious RCU usage > ----------------------------- > drivers/iommu/intel-iommu.c:5216 RCU-list traversed in non-reader section!! > > other info that might help us debug this: > > rcu_scheduler_active = 2, debug_locks = 1 > no locks held by swapper/0/1. > > Call Trace: > dump_stack+0xa0/0xea > lockdep_rcu_suspicious+0x102/0x10b > intel_iommu_init+0x947/0xb13 > pci_iommu_init+0x26/0x62 > do_one_initcall+0xfe/0x500 > kernel_init_freeable+0x45a/0x4f8 > kernel_init+0x11/0x139 > ret_from_fork+0x3a/0x50 > DMAR: Intel(R) Virtualization Technology for Directed I/O > > Fixes: d8190dc63886 ("iommu/vt-d: Enable DMA remapping after rmrr mapped") > Signed-off-by: Qian Cai Thanks for the fix. Acked-by: Lu Baolu Best regards, baolu > --- > drivers/iommu/intel-iommu.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 6fa6de2b6ad5..bc138ceb07bc 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -5193,6 +5193,7 @@ int __init intel_iommu_init(void) > > init_iommu_pm_ops(); > > + down_read(&dmar_global_lock); > for_each_active_iommu(iommu, drhd) { > iommu_device_sysfs_add(&iommu->iommu, NULL, > intel_iommu_groups, > @@ -5200,6 +5201,7 @@ int __init intel_iommu_init(void) > iommu_device_set_ops(&iommu->iommu, &intel_iommu_ops); > iommu_device_register(&iommu->iommu); > } > + up_read(&dmar_global_lock); > > bus_set_iommu(&pci_bus_type, &intel_iommu_ops); > if (si_domain && !hw_pass_through) > @@ -5210,7 +5212,6 @@ int __init intel_iommu_init(void) > 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) { > @@ -5219,6 +5220,8 @@ int __init intel_iommu_init(void) > > iommu_disable_protect_mem_regions(iommu); > } > + up_read(&dmar_global_lock); > + > pr_info("Intel(R) Virtualization Technology for Directed I/O\n"); > > intel_iommu_enabled = 1; > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu