Commit 9d4678eb authored Nov 30, 2019 by Andrea Arcangeli Committed by Linus Torvalds Dec 01, 2019

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@redhat.com


Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 643aa36e

fs/userfaultfd.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1460,7 +1460,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
		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),

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