--- linux-2.6.20.x86_64/mm/memory.c.flushme	2007-04-23 22:26:06.000000000 -0400
+++ linux-2.6.20.x86_64/mm/memory.c	2007-04-23 22:42:06.000000000 -0400
@@ -628,6 +628,7 @@ static unsigned long zap_pte_range(struc
 				long *zap_work, struct zap_details *details)
 {
 	struct mm_struct *mm = tlb->mm;
+	unsigned long start_addr = addr;
 	pte_t *pte;
 	spinlock_t *ptl;
 	int file_rss = 0;
@@ -726,6 +727,11 @@ static unsigned long zap_pte_range(struc
 
 	add_mm_rss(mm, file_rss, anon_rss);
 	arch_leave_lazy_mmu_mode();
+	if (details && details->madv_free) {
+		/* Protect against MADV_DONTNEED or unmap_mapping_range */
+		tlb_finish_mmu(tlb, start_addr, addr);
+		tlb = tlb_gather_mmu(mm, 0);
+	}
 	pte_unmap_unlock(pte - 1, ptl);
 
 	return addr;