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=-9.0 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=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 893CAC04AAF for ; Tue, 21 May 2019 07:37:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 664D62173E for ; Tue, 21 May 2019 07:37:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726680AbfEUHhM (ORCPT ); Tue, 21 May 2019 03:37:12 -0400 Received: from mga18.intel.com ([134.134.136.126]:4506 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726006AbfEUHhM (ORCPT ); Tue, 21 May 2019 03:37:12 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 May 2019 00:37:11 -0700 X-ExtLoop1: 1 Received: from allen-box.sh.intel.com ([10.239.159.136]) by orsmga005.jf.intel.com with ESMTP; 21 May 2019 00:37:09 -0700 From: Lu Baolu To: joro@8bytes.org, dwmw2@infradead.org Cc: ashok.raj@intel.com, jacob.jun.pan@linux.intel.com, Kevin Tian , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Dave Jiang Subject: [PATCH 1/2] iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock Date: Tue, 21 May 2019 15:30:15 +0800 Message-Id: <20190521073016.27525-1-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Jiang Lockdep debug reported lock inversion related with the iommu code caused by dmar_insert_one_dev_info() grabbing the iommu->lock and the device_domain_lock out of order versus the code path in iommu_flush_dev_iotlb(). Expanding the scope of the iommu->lock and reversing the order of lock acquisition fixes the issue. [ 76.238180] dsa_bus wq0.0: dsa wq wq0.0 disabled [ 76.248706] [ 76.250486] ======================================================== [ 76.257113] WARNING: possible irq lock inversion dependency detected [ 76.263736] 5.1.0-rc5+ #162 Not tainted [ 76.267854] -------------------------------------------------------- [ 76.274485] systemd-journal/521 just changed the state of lock: [ 76.280685] 0000000055b330f5 (device_domain_lock){..-.}, at: iommu_flush_dev_iotlb.part.63+0x29/0x90 [ 76.290099] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 76.297093] (&(&iommu->lock)->rlock){+.+.} [ 76.297094] [ 76.297094] [ 76.297094] and interrupts could create inverse lock ordering between them. [ 76.297094] [ 76.314257] [ 76.314257] other info that might help us debug this: [ 76.321448] Possible interrupt unsafe locking scenario: [ 76.321448] [ 76.328907] CPU0 CPU1 [ 76.333777] ---- ---- [ 76.338642] lock(&(&iommu->lock)->rlock); [ 76.343165] local_irq_disable(); [ 76.349422] lock(device_domain_lock); [ 76.356116] lock(&(&iommu->lock)->rlock); [ 76.363154] [ 76.366134] lock(device_domain_lock); [ 76.370548] [ 76.370548] *** DEADLOCK *** Fixes: 745f2586e78e ("iommu/vt-d: Simplify function get_domain_for_dev()") Signed-off-by: Dave Jiang Reviewed-by: Lu Baolu --- drivers/iommu/intel-iommu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index a209199f3af6..91f4912c09c6 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2512,6 +2512,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, } } + spin_lock(&iommu->lock); spin_lock_irqsave(&device_domain_lock, flags); if (dev) found = find_domain(dev); @@ -2527,17 +2528,16 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, if (found) { spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock(&iommu->lock); free_devinfo_mem(info); /* Caller must free the original domain */ return found; } - spin_lock(&iommu->lock); ret = domain_attach_iommu(domain, iommu); - spin_unlock(&iommu->lock); - if (ret) { spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock(&iommu->lock); free_devinfo_mem(info); return NULL; } @@ -2547,6 +2547,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, if (dev) dev->archdata.iommu = info; spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock(&iommu->lock); /* PASID table is mandatory for a PCI device in scalable mode. */ if (dev && dev_is_pci(dev) && sm_supported(iommu)) { -- 2.17.1