[PATCH 5.4 33/90] net/x25: Fix x25_neigh refcnt leak when x25 disconnect
From: Greg Kroah-Hartman
Date: Mon Aug 03 2020 - 08:29:22 EST
From: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
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()
Signed-off-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx>
Signed-off-by: Xin Tan <tanxin.ctf@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/x25/x25_subr.c | 4 ++++
1 file changed, 4 insertions(+)
@@ -357,6 +357,10 @@ void x25_disconnect(struct sock *sk, int
+ x25->neighbour = NULL;