net: Flush deferred skb free on socket destroy

The cited Fixes patch moved to a deferred skb approach where the skbs
are not freed immediately under the socket lock.  Add a WARN_ON_ONCE()
to verify the deferred list is empty on socket destroy, and empty it to
prevent potential memory leaks.

Fixes: f35f821935d8 ("tcp: defer skb freeing after socket lock is released")
Signed-off-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/sock.c b/net/core/sock.c
index f32ec08..4ff806d 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2049,6 +2049,9 @@ void sk_destruct(struct sock *sk)
 {
        bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE);
 
+       WARN_ON_ONCE(!llist_empty(&sk->defer_list));
+       sk_defer_free_flush(sk);
+
        if (rcu_access_pointer(sk->sk_reuseport_cb)) {
                reuseport_detach_sock(sk);
                use_call_rcu = true;