[Patch net] netrom: switch to sock timer API

[Patch net] netrom: switch to sock timer API

[Cong Wang]

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: syzbot+defa700d16f1bd1b9a05@syzkaller.appspotmail.com
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-hams@vger.kernel.org
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/netrom/nr_timer.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/net/netrom/nr_timer.c b/net/netrom/nr_timer.c
index cbd51ed5a2d7..908e53ab47a4 100644
--- a/net/netrom/nr_timer.c
+++ b/net/netrom/nr_timer.c
@@ -52,21 +52,21 @@ 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)
@@ -74,37 +74,37 @@ 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)
-- 
2.20.1

Re: [Patch net] netrom: switch to sock timer API

[David Miller]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu, 24 Jan 2019 14:18:18 -0800

> 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: syzbot+defa700d16f1bd1b9a05@syzkaller.appspotmail.com
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: linux-hams@vger.kernel.org
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Applied and queued up for -stable, thanks!