diff --git a/mm/memory.c b/mm/memory.c
index 3e50383..d86aa88 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3202,7 +3202,16 @@
 	pte_t entry;
 	spinlock_t *ptl;
 
-	entry = ACCESS_ONCE(*pte);
+	/*
+	 * some architectures can have larger ptes than wordsize,
+	 * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and CONFIG_32BIT=y,
+	 * so READ_ONCE or ACCESS_ONCE cannot guarantee atomic accesses.
+	 * The code below just needs a consistent view for the ifs and
+	 * we later double check anyway with the ptl lock held. So here
+	 * a barrier will do.
+	 */
+	entry = *pte;
+	barrier();
 	if (!pte_present(entry)) {
 		if (pte_none(entry)) {
 			if (vma->vm_ops) {