From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 05/39] batman-adv: Fix refcnt leak in batadv_show_throughput_override Date: Thu, 14 May 2020 14:54:22 -0400 Message-Id: <20200514185456.21060-5-sashal@kernel.org> In-Reply-To: <20200514185456.21060-1-sashal@kernel.org> References: <20200514185456.21060-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xiyu Yang , Xin Tan , Sven Eckelmann , Simon Wunderlich , Sasha Levin , b.a.t.m.a.n@lists.open-mesh.org, netdev@vger.kernel.org From: Xiyu Yang [ Upstream commit f872de8185acf1b48b954ba5bd8f9bc0a0d14016 ] batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(), which gets a batadv_hard_iface object from net_dev with increased refcnt and its reference is assigned to a local pointer 'hard_iface'. When batadv_show_throughput_override() returns, "hard_iface" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in the normal path of batadv_show_throughput_override(), which forgets to decrease the refcnt increased by batadv_hardif_get_by_netdev() before the function returns, causing a refcnt leak. Fix this issue by calling batadv_hardif_put() before the batadv_show_throughput_override() returns in the normal path. Fixes: 0b5ecc6811bd ("batman-adv: add throughput override attribute to hard_ifaces") Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Sasha Levin --- net/batman-adv/sysfs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c index 2ef9b136fc394..e44a7f29d598e 100644 --- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -1114,6 +1114,7 @@ static ssize_t batadv_show_throughput_override(struct kobject *kobj, tp_override = atomic_read(&hard_iface->bat_v.throughput_override); + batadv_hardif_put(hard_iface); return sprintf(buff, "%u.%u MBit\n", tp_override / 10, tp_override % 10); } -- 2.20.1