--- 2.2.13pre7/mm/page_alloc.c	Wed Sep 15 17:56:39 1999
+++ 2.2.13pre7-poison/mm/page_alloc.c	Wed Sep 15 17:55:35 1999
@@ -74,6 +74,13 @@
 	prev->next = next;
 }
 
+static unsigned long poison(unsigned long addr, unsigned long order)
+{
+	memset((char *) addr, 0x6b, PAGE_SIZE<<order);
+	*(unsigned char *)(addr+(PAGE_SIZE<<order)-1) = 0xb6;
+	return addr;
+}
+
 /*
  * Free_page() adds the page to the free lists. This is optimized for
  * fast normal cases (no error jumps taken normally).
@@ -129,6 +136,7 @@
 		if (PageSwapCache(page))
 			panic ("Freeing swap cache page");
 		page->flags &= ~(1 << PG_referenced);
+		poison(PAGE_OFFSET + PAGE_SIZE * (page - mem_map), order);
 		free_pages_ok(page - mem_map, order, PageDMA(page) ? 1 : 0);
 		return;
 	}
@@ -166,7 +174,7 @@
 			area->count--; \
 			EXPAND(ret, map_nr, order, new_order, area); \
 			spin_unlock_irqrestore(&page_alloc_lock, flags); \
-			return ADDRESS(map_nr); \
+			return poison(ADDRESS(map_nr), (order)); \
 		} \
 		new_order++; area++; \
 	} while (new_order < NR_MEM_LISTS); \