diff -urN 2.4.0-test4-pre6/mm/swapfile.c vm-25/mm/swapfile.c
--- 2.4.0-test4-pre6/mm/swapfile.c	Tue Jul 11 03:50:44 2000
+++ vm-25/mm/swapfile.c	Sat Jul 15 18:05:59 2000
@@ -315,10 +315,20 @@
 	 */
 	if (!mm)
 		return;
+	/*
+	 * Avoid the vmas to go away from under us
+	 * and also avoids the task to play with
+	 * pagetables under do_wp_page(). If the
+	 * vmlist_modify_lock wouldn't acquire the
+	 * mm->page_table_lock spinlock we should
+	 * acquire it by hand.
+	 */
+	vmlist_access_lock(mm);
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
 		pgd_t * pgd = pgd_offset(mm, vma->vm_start);
 		unuse_vma(vma, pgd, entry, page);
 	}
+	vmlist_access_unlock(mm);
 	return;
 }