Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752068AbdHHK0p (ORCPT ); Tue, 8 Aug 2017 06:26:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58472 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751464AbdHHK0o (ORCPT ); Tue, 8 Aug 2017 06:26:44 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A95A2C057FA6 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=asavkov@redhat.com From: Artem Savkov To: Will Deacon Cc: Vivek Gautam , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Artem Savkov Subject: [PATCH v2] iommu/arm-smmu: fix null-pointer dereference in arm_smmu_add_device Date: Tue, 8 Aug 2017 12:26:02 +0200 Message-Id: <1502187962-16861-1-git-send-email-asavkov@redhat.com> In-Reply-To: <20170808092614.GB12887@arm.com> References: <20170808092614.GB12887@arm.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 08 Aug 2017 10:26:44 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1109 Lines: 31 Commit c54451a "iommu/arm-smmu: Fix the error path in arm_smmu_add_device" removed fwspec assignment in legacy_binding path as redundant which is wrong. It needs to be updated after fwspec initialisation in arm_smmu_register_legacy_master() as it is dereferenced later. Without this there is a NULL-pointer dereference panic during boot on some hosts. Signed-off-by: Artem Savkov --- drivers/iommu/arm-smmu.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index b97188a..2d80fa8 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1519,6 +1519,13 @@ static int arm_smmu_add_device(struct device *dev) if (using_legacy_binding) { ret = arm_smmu_register_legacy_master(dev, &smmu); + + /* + * If dev->iommu_fwspec is initally NULL, arm_smmu_register_legacy_master() + * will allocate/initialise a new one. Thus we need to update fwspec for + * later use. + */ + fwspec = dev->iommu_fwspec; if (ret) goto out_free; } else if (fwspec && fwspec->ops == &arm_smmu_ops) { -- 2.7.5