1 files changed, 7 insertions, 0 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 131fd35ae39d..bff20cc56130 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -627,6 +627,13 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
                 if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
                         goto fallback;
 
+                /*
+                 * TODO: teach vmf_insert_pfn_pmd() to support
+                 * 'pte_special' for pmds
+                 */
+                if (pfn_valid(pfn))
+                        goto fallback;
+
                 if (buffer_unwritten(&bh) || buffer_new(&bh)) {
                         int i;
                         for (i = 0; i < PTRS_PER_PMD; i++)