--- linux/ipc/shm.c.orig	2003-04-28 11:19:24.000000000 -0700
+++ linux/ipc/shm.c	2003-05-09 13:26:13.000000000 -0700
@@ -600,7 +600,7 @@
 		if (addr & (SHMLBA-1)) {
 			if (shmflg & SHM_RND)
 				addr &= ~(SHMLBA-1);	   /* round down */
-			else
+			else if (addr & ~PAGE_MASK)
 				return -EINVAL;
 		}
 		flags = MAP_SHARED | MAP_FIXED;