dax: fix __dax_pmd_fault crash

[uclinux-h8/linux.git] / fs / dax.c

diff --git a/fs/dax.c b/fs/dax.c
index 131fd35..bff20cc 100644 (file)
--- 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++)