diff --git a/src/internal/poll/writev.go b/src/internal/poll/writev.go
index 04e3522d8a..a48a38be08 100644
--- a/src/internal/poll/writev.go
+++ b/src/internal/poll/writev.go
@@ -51,7 +51,10 @@ func (fd *FD) Writev(v *[][]byte) (int64, error) {
 		if len(iovecs) == 0 {
 			break
 		}
-		fd.iovecs = &iovecs // cache
+		if fd.iovecs == nil {
+			fd.iovecs = new([]syscall.Iovec)
+		}
+		*fd.iovecs = iovecs // cache
 
 		var wrote uintptr
 		wrote, err = writev(fd.Sysfd, iovecs)