patch-2.4.0-test8 linux/kernel/ptrace.c

• Lines: 15
• Date: Fri Sep 8 12:41:04 2000
• Orig file: v2.4.0-test7/linux/kernel/ptrace.c
• Orig date: Wed Aug 9 19:19:51 2000

diff -u --recursive --new-file v2.4.0-test7/linux/kernel/ptrace.c linux/kernel/ptrace.c
@@ -44,8 +44,12 @@
 	if (write && (!pte_write(*pgtable) || !pte_dirty(*pgtable)))
 		goto fault_in_page;
 	page = pte_page(*pgtable);
-	if ((!VALID_PAGE(page)) || PageReserved(page))
-		return 0;
+
+	/* ZERO_PAGE is special: reads from it are ok even though it's marked reserved */
+	if (page != ZERO_PAGE(addr) || write) {
+		if ((!VALID_PAGE(page)) || PageReserved(page))
+			return 0;
+	}
 	flush_cache_page(vma, addr);
 
 	if (write) {