From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: <20170808092614.GB12887@arm.com> Return-path: In-Reply-To: <20170808092614.GB12887@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Will Deacon Cc: Vivek Gautam , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Artem Savkov List-Id: iommu@lists.linux-foundation.org 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