The patch titled
Subject: fs/userfaultfd.c: wp: clear VM_UFFD_MISSING or VM_UFFD_WP during userfaultfd_register()
has been added to the -mm tree. Its filename is
uffd-wp-clear-vm_uffd_missing-or-vm_uffd_wp-during-userfaultfd_register.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/uffd-wp-clear-vm_uffd_missing-or-vm_uffd_wp-during-userfaultfd_register.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/uffd-wp-clear-vm_uffd_missing-or-vm_uffd_wp-during-userfaultfd_register.patch
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------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: fs/userfaultfd.c: wp: clear VM_UFFD_MISSING or VM_UFFD_WP during userfaultfd_register()
If the registration is repeated without VM_UFFD_MISSING or VM_UFFD_WP they
need to be cleared. Currently setting UFFDIO_REGISTER_MODE_WP returns
-EINVAL, so this patch is a noop until the UFFDIO_REGISTER_MODE_WP support
is applied.
Link: http://lkml.kernel.org/r/20191004232834.GP13922@xxxxxxxxxx
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reported-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Reviewed-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/userfaultfd.c~uffd-wp-clear-vm_uffd_missing-or-vm_uffd_wp-during-userfaultfd_register
+++ a/fs/userfaultfd.c
@@ -1460,7 +1460,8 @@ static int userfaultfd_register(struct u
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
- new_flags = (vma->vm_flags & ~vm_flags) | vm_flags;
+ new_flags = (vma->vm_flags &
+ ~(VM_UFFD_MISSING|VM_UFFD_WP)) | vm_flags;
prev = vma_merge(mm, prev, start, vma_end, new_flags,
vma->anon_vma, vma->vm_file, vma->vm_pgoff,
vma_policy(vma),
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
uffd-wp-clear-vm_uffd_missing-or-vm_uffd_wp-during-userfaultfd_register.patch
