From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
To: Andrew Hendry <andrew.hendry@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Xiyu Yang <xiyuyang19@fudan.edu.cn>,
Xin Tan <tanxin.ctf@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Allison Randal <allison@lohutok.net>,
Thomas Gleixner <tglx@linutronix.de>,
linux-x25@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: yuanxzhang@fudan.edu.cn, kjlu@umn.edu
Subject: [PATCH v2] net/x25: Fix x25_neigh refcnt leak when x25 disconnect
Date: Sat, 25 Apr 2020 21:06:25 +0800 [thread overview]
Message-ID: <1587819994-40137-1-git-send-email-xiyuyang19@fudan.edu.cn> (raw)
x25_connect() invokes x25_get_neigh(), which returns a reference of the
specified x25_neigh object to "x25->neighbour" with increased refcnt.
When x25 connect success and returns, the reference still be hold by
"x25->neighbour", so the refcount should be decreased in
x25_disconnect() to keep refcount balanced.
The reference counting issue happens in x25_disconnect(), which forgets
to decrease the refcnt increased by x25_get_neigh() in x25_connect(),
causing a refcnt leak.
Fix this issue by calling x25_neigh_put() before x25_disconnect()
returns.
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
Changes in v2:
- Fix x25_neigh refcnt leak in x25_disconnect() rather than in
x25_connect()
---
net/x25/x25_subr.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
index 8aa415a38814..8b1b06cabcbf 100644
--- a/net/x25/x25_subr.c
+++ b/net/x25/x25_subr.c
@@ -357,6 +357,10 @@ void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
sk->sk_state_change(sk);
sock_set_flag(sk, SOCK_DEAD);
}
+ read_lock_bh(&x25_list_lock);
+ x25_neigh_put(x25->neighbour);
+ x25->neighbour = NULL;
+ read_unlock_bh(&x25_list_lock);
}
/*
--
2.7.4
next reply other threads:[~2020-04-25 13:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-25 13:06 Xiyu Yang [this message]
2020-04-27 18:20 ` [PATCH v2] net/x25: Fix x25_neigh refcnt leak when x25 disconnect David Miller
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