4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Andrea Arcangeli <[email protected]> commit 01e881f5a1fca4677e82733061868c6d6ea05ca7 upstream. Calling UFFDIO_UNREGISTER on virtual ranges not yet registered in uffd could trigger an harmless false positive WARN_ON. Check the vma is already registered before checking VM_MAYWRITE to shut off the false positive warning. Link: http://lkml.kernel.org/r/[email protected] Cc: <[email protected]> Fixes: 29ec90660d68 ("userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas") Signed-off-by: Andrea Arcangeli <[email protected]> Reported-by: [email protected] Acked-by: Mike Rapoport <[email protected]> Acked-by: Hugh Dickins <[email protected]> Acked-by: Peter Xu <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/userfaultfd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1567,7 +1567,6 @@ static int userfaultfd_unregister(struct cond_resched(); BUG_ON(!vma_can_userfault(vma)); - WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); /* * Nothing to do: this vma is already registered into this @@ -1576,6 +1575,8 @@ static int userfaultfd_unregister(struct if (!vma->vm_userfaultfd_ctx.ctx) goto skip; + WARN_ON(!(vma->vm_flags & VM_MAYWRITE)); + if (vma->vm_start > start) start = vma->vm_start; vma_end = min(end, vma->vm_end);
