net/smc: fix 'workqueue leaked lock' in smc_conn_abort_work

The abort_work is scheduled when a connection was detected to be
out-of-sync after a link failure. The work calls smc_conn_kill(),
which calls smc_close_active_abort() and that might end up calling
smc_close_cancel_work().
smc_close_cancel_work() cancels any pending close_work and tx_work but
needs to release the sock_lock before and acquires the sock_lock again
afterwards. So when the sock_lock was NOT acquired before then it may
be held after the abort_work completes. Thats why the sock_lock is
acquired before the call to smc_conn_kill() in __smc_lgr_terminate(),
but this is missing in smc_conn_abort_work().

Fix that by acquiring the sock_lock first and release it after the
call to smc_conn_kill().

Fixes: b286a065 ("net/smc: handle incoming CDC validation message")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_core.c

@@ -1474,7 +1474,9 @@ static void smc_conn_abort_work(struct work_struct *work)
 						   abort_work);
 	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
 
+	lock_sock(&smc->sk);
 	smc_conn_kill(conn, true);
+	release_sock(&smc->sk);
 	sock_put(&smc->sk); /* sock_hold done by schedulers of abort_work */
 }