net/smc: put sk reference if close work was canceled

Note that we always hold a reference to sock when attempting
to submit close_work. Therefore, if we have successfully
canceled close_work from pending, we MUST release that reference
to avoid potential leaks.

Fixes: 42bfba9e ("net/smc: immediate termination for SMCD link groups")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_close.c

@@ -116,7 +116,8 @@ static void smc_close_cancel_work(struct smc_sock *smc)
 	struct sock *sk = &smc->sk;
 
 	release_sock(sk);
-	cancel_work_sync(&smc->conn.close_work);
+	if (cancel_work_sync(&smc->conn.close_work))
+		sock_put(sk);
 	cancel_delayed_work_sync(&smc->conn.tx_work);
 	lock_sock(sk);
 }