userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb

In mfill_atomic_hugetlb(), mmap_changing isn't being checked
again if we drop mmap_lock and reacquire it. When the lock is not held,
mmap_changing could have been incremented. This is also inconsistent
with the behavior in mfill_atomic().

Link: https://lkml.kernel.org/r/[email protected]
Fixes: df2cc96e77011 ("userfaultfd: prevent non-cooperative events vs mcopy_atomic races") 
Signed-off-by: Lokesh Gidra <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Axel Rasmussen <[email protected]>
Cc: Brian Geffon <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Kalesh Singh <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Nicolas Geoffray <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions