diff --git a/arch/x86_64/bits/signal.h b/arch/x86_64/bits/signal.h
index b4220fe2..71b656b5 100644
--- a/arch/x86_64/bits/signal.h
+++ b/arch/x86_64/bits/signal.h
@@ -20,7 +20,7 @@
 #define REG_RSP         15
 #define REG_RIP         16
 #define REG_EFL         17
-#define REG_CSGFS       18
+#define REG_CSGSFS      18
 #define REG_ERR         19
 #define REG_TRAPNO      20
 #define REG_OLDMASK     21