diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 54f82c341e20..2c31e82cb953 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -48,6 +48,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
 	req.len = optlen;
 	if (!bpfilter_ops.info.tgid)
 		goto out;
+	pos = 0;
 	n = kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
 			   &pos);
 	if (n != sizeof(req)) {