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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Xin Tan <tanxin.ctf@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 06/18] wimax/i2400m: Fix potential urb refcnt leak
Date:   Fri,  8 May 2020 14:35:09 +0200
Message-Id: <20200508123032.466947258@linuxfoundation.org>
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From: Xiyu Yang <xiyuyang19@fudan.edu.cn>

[ Upstream commit 7717cbec172c3554d470023b4020d5781961187e ]

i2400mu_bus_bm_wait_for_ack() invokes usb_get_urb(), which increases the
refcount of the "notif_urb".

When i2400mu_bus_bm_wait_for_ack() returns, local variable "notif_urb"
becomes invalid, so the refcount should be decreased to keep refcount
balanced.

The issue happens in all paths of i2400mu_bus_bm_wait_for_ack(), which
forget to decrease the refcnt increased by usb_get_urb(), causing a
refcnt leak.

Fix this issue by calling usb_put_urb() before the
i2400mu_bus_bm_wait_for_ack() 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: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wimax/i2400m/usb-fw.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wimax/i2400m/usb-fw.c b/drivers/net/wimax/i2400m/usb-fw.c
index e74664b84925e..4e4167976acf6 100644
--- a/drivers/net/wimax/i2400m/usb-fw.c
+++ b/drivers/net/wimax/i2400m/usb-fw.c
@@ -354,6 +354,7 @@ ssize_t i2400mu_bus_bm_wait_for_ack(struct i2400m *i2400m,
 		usb_autopm_put_interface(i2400mu->usb_iface);
 	d_fnend(8, dev, "(i2400m %p ack %p size %zu) = %ld\n",
 		i2400m, ack, ack_size, (long) result);
+	usb_put_urb(&notif_urb);
 	return result;
 
 error_exceeded:
-- 
2.20.1