diff --git a/src/pkg/runtime/linux/amd64/sys.s b/src/pkg/runtime/linux/amd64/sys.s
index 7e0fffc656b..73db9d75961 100644
--- a/src/pkg/runtime/linux/amd64/sys.s
+++ b/src/pkg/runtime/linux/amd64/sys.s
@@ -108,7 +108,7 @@ TEXT	·mmap(SB),7,$0
 	INCQ	AX
 	RET
 
-TEXT	munmap(SB),7,$0
+TEXT	·munmap(SB),7,$0
 	MOVQ	8(SP), DI
 	MOVQ	16(SP), SI
 	MOVQ	$11, AX	// munmap