diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c08e06d..93316a9 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -60,6 +60,7 @@
 int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
 
 int sysctl_tcp_cookie_size __read_mostly = 0; /* TCP_COOKIE_MAX */
+EXPORT_SYMBOL_GPL(sysctl_tcp_cookie_size);
 
 
 /* Account for new data that has been sent to the network. */