[PATCH net-next] tcp: md5: Handle RCU dereference of md5sig_info

[Mat Martineau]

Dereference tp->md5sig_info in tcp_v4_destroy_sock() the same way it is
done in the adjacent call to tcp_clear_md5_list().

Resolves this sparse warning:

net/ipv4/tcp_ipv4.c:1914:17: warning: incorrect type in argument 1 (different 
address spaces)
net/ipv4/tcp_ipv4.c:1914:17:    expected struct callback_head *head
net/ipv4/tcp_ipv4.c:1914:17:    got struct callback_head [noderef] 
<asn:4>*<noident>

Signed-off-by: Mat Martineau <mathew.j.martin...@linux.intel.com>
---
 net/ipv4/tcp_ipv4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index dd945b114215..5d203248123e 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1911,7 +1911,7 @@ void tcp_v4_destroy_sock(struct sock *sk)
        /* Clean up the MD5 key list, if any */
        if (tp->md5sig_info) {
                tcp_clear_md5_list(sk);
-               kfree_rcu(tp->md5sig_info, rcu);
+               kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
                tp->md5sig_info = NULL;
        }
 #endif
-- 
2.15.1