Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 024/212] net/x25: Fix x25_neigh refcnt leak when x25 disconnect | Date | Thu, 20 Aug 2020 11:19:57 +0200 |
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From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
commit 4becb7ee5b3d2829ed7b9261a245a77d5b7de902 upstream.
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> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/x25/x25_subr.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/net/x25/x25_subr.c +++ b/net/x25/x25_subr.c @@ -368,6 +368,10 @@ void x25_disconnect(struct sock *sk, int 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); } /*
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