Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756034AbdGCONo (ORCPT ); Mon, 3 Jul 2017 10:13:44 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37606 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933189AbdGCNqS (ORCPT ); Mon, 3 Jul 2017 09:46:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pan Bian , Joerg Roedel Subject: [PATCH 4.9 159/172] iommu/amd: Fix incorrect error handling in amd_iommu_bind_pasid() Date: Mon, 3 Jul 2017 15:35:39 +0200 Message-Id: <20170703133421.792478192@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170703133414.260777365@linuxfoundation.org> References: <20170703133414.260777365@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1040 Lines: 37 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pan Bian commit 73dbd4a4230216b6a5540a362edceae0c9b4876b upstream. In function amd_iommu_bind_pasid(), the control flow jumps to label out_free when pasid_state->mm and mm is NULL. And mmput(mm) is called. In function mmput(mm), mm is referenced without validation. This will result in a NULL dereference bug. This patch fixes the bug. Signed-off-by: Pan Bian Fixes: f0aac63b873b ('iommu/amd: Don't hold a reference to mm_struct') Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/amd_iommu_v2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/iommu/amd_iommu_v2.c +++ b/drivers/iommu/amd_iommu_v2.c @@ -695,9 +695,9 @@ out_clear_state: out_unregister: mmu_notifier_unregister(&pasid_state->mn, mm); + mmput(mm); out_free: - mmput(mm); free_pasid_state(pasid_state); out: