diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b393536..027f7ab 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -486,12 +486,14 @@
 {
 	struct tun_file *tfile = file->private_data;
 	struct tun_struct *tun = __tun_get(tfile);
-	struct sock *sk = tun->sk;
+	struct sock *sk;
 	unsigned int mask = 0;
 
 	if (!tun)
 		return POLLERR;
 
+	sk = tun->sk;
+
 	DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 
 	poll_wait(file, &tun->socket.wait, wait);