diff --git a/unix/syscall_linux_arm64.go b/unix/syscall_linux_arm64.go
index 9a8e6e41..c464783d 100644
--- a/unix/syscall_linux_arm64.go
+++ b/unix/syscall_linux_arm64.go
@@ -23,8 +23,11 @@ package unix
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 
 func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
-	ts := Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
-	return Pselect(nfd, r, w, e, &ts, nil)
+	var ts *Timespec
+	if timeout != nil {
+		ts = &Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
+	}
+	return Pselect(nfd, r, w, e, ts, nil)
 }
 
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)
diff --git a/unix/syscall_linux_mips64x.go b/unix/syscall_linux_mips64x.go
index 46aa4ff9..15a69cbd 100644
--- a/unix/syscall_linux_mips64x.go
+++ b/unix/syscall_linux_mips64x.go
@@ -26,8 +26,11 @@ package unix
 //sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
 
 func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
-	ts := Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
-	return Pselect(nfd, r, w, e, &ts, nil)
+	var ts *Timespec
+	if timeout != nil {
+		ts = &Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
+	}
+	return Pselect(nfd, r, w, e, ts, nil)
 }
 
 //sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)