diff --git a/src/pkg/syscall/exec_plan9.go b/src/pkg/syscall/exec_plan9.go
index 94ec395d6d..962b39b780 100644
--- a/src/pkg/syscall/exec_plan9.go
+++ b/src/pkg/syscall/exec_plan9.go
@@ -363,7 +363,7 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err Error)
 	p[1] = -1
 
 	// Convert args to C form.
-	argv0p := StringBytePtr(argv[0])
+	argv0p := StringBytePtr(argv0)
 	argvp := StringArrayPtr(argv)
 
 	var chroot *byte