diff --git a/src/thread/i386/__set_thread_area.s b/src/thread/i386/__set_thread_area.s
index ad5381513804787fcd6969e8552c6904041425cb..1d852689faed383561c41db9bb408db6dfe08cc8 100644
--- a/src/thread/i386/__set_thread_area.s
+++ b/src/thread/i386/__set_thread_area.s
@@ -6,7 +6,11 @@ __set_thread_area:
 	push $0x51
 	push $0xfffff
 	push 16(%esp)
-	push $-1
+	xor %edx,%edx
+	mov %gs,%dx
+	sub $3,%edx
+	sar $3,%edx
+	push %edx
 	mov %esp,%ebx
 	xor %eax,%eax
 	mov $243,%al