[SRU Bionic/Focal/Impish/OEM-5.14] can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path

[Thadeu Lima de Souza Cascardo]

From: Hangyu Hua <hbh25y at gmail.com>

There is no need to call dev_kfree_skb() when usb_submit_urb() fails
beacause can_put_echo_skb() deletes the original skb and
can_free_echo_skb() deletes the cloned skb.

Link: https://lore.kernel.org/all/20220228083639.38183-1-hbh25y@gmail.com
Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface")
Cc: stable at vger.kernel.org
Cc: Sebastian Haas <haas at ems-wuensche.com>
Signed-off-by: Hangyu Hua <hbh25y at gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
(cherry picked from commit c70222752228a62135cee3409dccefd494a24646)
CVE-2022-28390
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
---

Fix is already pending on Jammy.

---
 drivers/net/can/usb/ems_usb.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 047348033e27..25fc17fd2756 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -827,7 +827,6 @@ static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *ne
 
 		usb_unanchor_urb(urb);
 		usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
-		dev_kfree_skb(skb);
 
 		atomic_dec(&dev->active_tx_urbs);
 
-- 
2.32.0