Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "6 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/memblock.c: reversed logic in memblock_discard()
  fork: fix incorrect fput of ->exe_file causing use-after-free
  mm/madvise.c: fix freeing of locked page with MADV_FREE
  dax: fix deadlock due to misaligned PMD faults
  mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled
  PM/hibernate: touch NMI watchdog when creating snapshot

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 306c2b603fb8..865d42c63e23 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1383,6 +1383,16 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
 
 	trace_dax_pmd_fault(inode, vmf, max_pgoff, 0);
 
+	/*
+	 * Make sure that the faulting address's PMD offset (color) matches
+	 * the PMD offset from the start of the file.  This is necessary so
+	 * that a PMD range in the page table overlaps exactly with a PMD
+	 * range in the radix tree.
+	 */
+	if ((vmf->pgoff & PG_PMD_COLOUR) !=
+	    ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR))
+		goto fallback;
+
 	/* Fall back to PTEs if we're going to COW */
 	if (write && !(vma->vm_flags & VM_SHARED))
 		goto fallback;