netrom: switch to sock timer API

sk_reset_timer() and sk_stop_timer() properly handle
sock refcnt for timer function. Switching to them
could fix a refcounting bug reported by syzbot.

Reported-and-tested-by: [email protected]
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: congwang

net/netrom/nr_timer.c

@@ -52,59 +52,59 @@ void nr_start_t1timer(struct sock *sk)
 {
 	struct nr_sock *nr = nr_sk(sk);
 
-	mod_timer(&nr->t1timer, jiffies + nr->t1);
+	sk_reset_timer(sk, &nr->t1timer, jiffies + nr->t1);
 }
 
 void nr_start_t2timer(struct sock *sk)
 {
 	struct nr_sock *nr = nr_sk(sk);
 
-	mod_timer(&nr->t2timer, jiffies + nr->t2);
+	sk_reset_timer(sk, &nr->t2timer, jiffies + nr->t2);
 }
 
 void nr_start_t4timer(struct sock *sk)
 {
 	struct nr_sock *nr = nr_sk(sk);
 
-	mod_timer(&nr->t4timer, jiffies + nr->t4);
+	sk_reset_timer(sk, &nr->t4timer, jiffies + nr->t4);
 }
 
 void nr_start_idletimer(struct sock *sk)
 {
 	struct nr_sock *nr = nr_sk(sk);
 
 	if (nr->idle > 0)
-		mod_timer(&nr->idletimer, jiffies + nr->idle);
+		sk_reset_timer(sk, &nr->idletimer, jiffies + nr->idle);
 }
 
 void nr_start_heartbeat(struct sock *sk)
 {
-	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
+	sk_reset_timer(sk, &sk->sk_timer, jiffies + 5 * HZ);
 }
 
 void nr_stop_t1timer(struct sock *sk)
 {
-	del_timer(&nr_sk(sk)->t1timer);
+	sk_stop_timer(sk, &nr_sk(sk)->t1timer);
 }
 
 void nr_stop_t2timer(struct sock *sk)
 {
-	del_timer(&nr_sk(sk)->t2timer);
+	sk_stop_timer(sk, &nr_sk(sk)->t2timer);
 }
 
 void nr_stop_t4timer(struct sock *sk)
 {
-	del_timer(&nr_sk(sk)->t4timer);
+	sk_stop_timer(sk, &nr_sk(sk)->t4timer);
 }
 
 void nr_stop_idletimer(struct sock *sk)
 {
-	del_timer(&nr_sk(sk)->idletimer);
+	sk_stop_timer(sk, &nr_sk(sk)->idletimer);
 }
 
 void nr_stop_heartbeat(struct sock *sk)
 {
-	del_timer(&sk->sk_timer);
+	sk_stop_timer(sk, &sk->sk_timer);
 }
 
 int nr_t1timer_running(struct sock *sk)