From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754710AbdBGPDC (ORCPT ); Tue, 7 Feb 2017 10:03:02 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35934 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754007AbdBGPDA (ORCPT ); Tue, 7 Feb 2017 10:03:00 -0500 Date: Tue, 7 Feb 2017 17:02:50 +0200 From: Mike Rapoport To: Andrew Morton Cc: Andrea Arcangeli , "Dr. David Alan Gilbert" , Hillf Danton , Mike Kravetz , Pavel Emelyanov , Linux-MM , LKML Subject: [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17020715-0032-0000-0000-00000718B265 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17020715-0033-0000-0000-000023582945 Message-Id: <20170207150249.GA6709@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-02-07_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702070143 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Andrew, The patch below is an incremental fixup for concerns Andrea raised at [1]. Please let me know if you prefer me to update the original patch and resend. [1] http://www.spinics.net/lists/linux-mm/msg121267.html -- Sincerely yours, Mike. >>From 8acff65ecee8ca4cc892d35b45125c34568d1c93 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Tue, 7 Feb 2017 11:50:17 +0200 Subject: [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT As Andrea commented in [1], if the VMA covering the address was unmapped, we may end up with a VMA a way above the faulting address. In this case we would like to return -ENOENT to allow uffd monitor detection of VMA removal. [1] http://www.spinics.net/lists/linux-mm/msg121267.html Signed-off-by: Mike Rapoport --- mm/userfaultfd.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index b861cf9..cf43456 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -206,6 +206,10 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, if (!dst_vma->vm_userfaultfd_ctx.ctx) goto out_unlock; + if (dst_start < dst_vma->vm_start || + dst_start + len > dst_vma->vm_end) + goto out_unlock; + err = -EINVAL; if (vma_hpagesize != vma_kernel_pagesize(dst_vma)) goto out_unlock; @@ -216,9 +220,6 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, */ if (dst_vma->vm_flags & VM_SHARED) goto out_unlock; - if (dst_start < dst_vma->vm_start || - dst_start + len > dst_vma->vm_end) - goto out_unlock; } if (WARN_ON(dst_addr & (vma_hpagesize - 1) || @@ -385,13 +386,14 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, if (!dst_vma->vm_userfaultfd_ctx.ctx) goto out_unlock; - err = -EINVAL; - if (!vma_is_shmem(dst_vma) && dst_vma->vm_flags & VM_SHARED) - goto out_unlock; if (dst_start < dst_vma->vm_start || dst_start + len > dst_vma->vm_end) goto out_unlock; + err = -EINVAL; + if (!vma_is_shmem(dst_vma) && dst_vma->vm_flags & VM_SHARED) + goto out_unlock; + /* * If this is a HUGETLB vma, pass off to appropriate routine */ -- 1.9.1