decnet: proper socket refcounting

Better use sk_reset_timer() / sk_stop_timer() helpers to make sure we
dont access already freed/reused memory later.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 12 deletions

diff --git a/net/decnet/dn_timer.c b/net/decnet/dn_timer.c
index 67f691bd4acf..d9c150cc59a9 100644
--- a/net/decnet/dn_timer.c
+++ b/net/decnet/dn_timer.c
@@ -36,16 +36,13 @@ static void dn_slow_timer(unsigned long arg);
 
 void dn_start_slow_timer(struct sock *sk)
 {
-        sk->sk_timer.expires    = jiffies + SLOW_INTERVAL;
-        sk->sk_timer.function   = dn_slow_timer;
-        sk->sk_timer.data       = (unsigned long)sk;
-
-        add_timer(&sk->sk_timer);
+        setup_timer(&sk->sk_timer, dn_slow_timer, (unsigned long)sk);
+        sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL);
 }
 
 void dn_stop_slow_timer(struct sock *sk)
 {
-        del_timer(&sk->sk_timer);
+        sk_stop_timer(sk, &sk->sk_timer);
 }
 
 static void dn_slow_timer(unsigned long arg)
@@ -53,12 +50,10 @@ static void dn_slow_timer(unsigned long arg)
         struct sock *sk = (struct sock *)arg;
         struct dn_scp *scp = DN_SK(sk);
 
-        sock_hold(sk);
         bh_lock_sock(sk);
 
         if (sock_owned_by_user(sk)) {
-                sk->sk_timer.expires = jiffies + HZ / 10;
-                add_timer(&sk->sk_timer);
+                sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ / 10);
                 goto out;
         }
 
@@ -100,9 +95,7 @@ static void dn_slow_timer(unsigned long arg)
                         scp->keepalive_fxn(sk);
         }
 
-        sk->sk_timer.expires = jiffies + SLOW_INTERVAL;
-
-        add_timer(&sk->sk_timer);
+        sk_reset_timer(sk, &sk->sk_timer, jiffies + SLOW_INTERVAL);
 out:
         bh_unlock_sock(sk);
         sock_put(sk);