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;