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=-9.1 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 046ADC48BD3 for ; Wed, 26 Jun 2019 03:41:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D3CBF216C8 for ; Wed, 26 Jun 2019 03:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561520502; bh=zBEPaQqOj3fGcLAaqSuufXrZfsGV2qN2uatpayqbZSk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ybhZXSSreLsp114KJxLU3lx6Ea186SVNDuYbhjsvYh2rPMwSu1Grm3QUfstVP/OEa Mzaon8obpDQv1m3mNwHSFsSOmxSMQPS+z+XGxEqMAux1G0I3H/VMUaDEV0lHtAtJiO SDfT5dsooKD1c4bVxRxWi3Re7Omdtwt3Ep9/FFEY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726865AbfFZDll (ORCPT ); Tue, 25 Jun 2019 23:41:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:52060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726819AbfFZDlj (ORCPT ); Tue, 25 Jun 2019 23:41:39 -0400 Received: from sasha-vm.mshome.net (mobile-107-77-172-74.mobile.att.net [107.77.172.74]) (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 F35F920659; Wed, 26 Jun 2019 03:41:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561520498; bh=zBEPaQqOj3fGcLAaqSuufXrZfsGV2qN2uatpayqbZSk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L94tbbewMH46tmZ3rMBTEslETwZ8lNcVAmaQFJ/BeLY2jFWw0I2hkwMBzbvRkEFN/ M7pwZVTSUdDnqpcc/o40lLl5QBHnsva4DtzWf9CvlUzF9sMZPOFVlrymPn6XMhaRFc iAYlgohaMqJBoQaQ1SW86DHZi9z8br7lcI8+Qysw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dave Jiang , Lu Baolu , Joerg Roedel , Sasha Levin , iommu@lists.linux-foundation.org Subject: [PATCH AUTOSEL 5.1 09/51] iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock Date: Tue, 25 Jun 2019 23:40:25 -0400 Message-Id: <20190626034117.23247-9-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190626034117.23247-1-sashal@kernel.org> References: <20190626034117.23247-1-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: Dave Jiang [ Upstream commit 7560cc3ca7d9d11555f80c830544e463fcdb28b8 ] 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 Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- 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 0feb3f70da16..c82d5f1bd306 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2509,6 +2509,7 @@ 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); @@ -2524,17 +2525,16 @@ 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; } @@ -2544,6 +2544,7 @@ 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)) { -- 2.20.1