* [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT
@ 2017-02-07 15:02 ` Mike Rapoport
0 siblings, 0 replies; 4+ messages in thread
From: Mike Rapoport @ 2017-02-07 15:02 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrea Arcangeli, Dr. David Alan Gilbert, Hillf Danton,
Mike Kravetz, Pavel Emelyanov, Linux-MM, LKML
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 <rppt@linux.vnet.ibm.com>
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 <rppt@linux.vnet.ibm.com>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT
2017-02-07 15:02 ` Mike Rapoport
@ 2017-02-07 20:06 ` Andrea Arcangeli
-1 siblings, 0 replies; 4+ messages in thread
From: Andrea Arcangeli @ 2017-02-07 20:06 UTC (permalink / raw)
To: Mike Rapoport
Cc: Andrew Morton, Dr. David Alan Gilbert, Hillf Danton, Mike Kravetz,
Pavel Emelyanov, Linux-MM, LKML
On Tue, Feb 07, 2017 at 05:02:50PM +0200, Mike Rapoport wrote:
> 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 <rppt@linux.vnet.ibm.com>
> 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 <rppt@linux.vnet.ibm.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
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^ permalink raw reply [flat|nested] 4+ messages in thread