[PATCH 5.15.y 2/2] can: esd_usb: kill anchored URBs before freeing netdevs

[Sasha Levin <sashal@kernel.org>]

From: Fan Wu <fanwu01@zju.edu.cn>

[ Upstream commit c43122fef328a70045fe7621c06de6b2b8e19264 ]

esd_usb_disconnect() frees each CAN netdev with free_candev() inside
its per-netdev loop and only calls unlink_all_urbs(dev) afterwards.
The per-netdev private data (struct esd_usb_net_priv) is embedded in
the net_device allocation returned by alloc_candev(), so once
free_candev() has run, dev->nets[i] points to freed memory.
unlink_all_urbs() then dereferences the freed dev->nets[i] to kill the
per-netdev TX anchor (usb_kill_anchored_urbs(&priv->tx_submitted)),
clear active_tx_jobs, and reset priv->tx_contexts[].

Reorder the teardown so the anchored URBs are killed before the netdevs
are freed, matching other CAN/USB drivers in the same directory such as
ems_usb, usb_8dev and mcba_usb, which unregister, then unlink, then
free: unregister the netdevs first (which stops their TX queues), call
unlink_all_urbs(dev) once, then free the netdevs.

This issue was found by an in-house static analysis tool.

Fixes: 96d8e90382dc ("can: Add driver for esd CAN-USB/2 device")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.5
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Link: https://patch.msgid.link/20260709164159.497640-1-fanwu01@zju.edu.cn
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/can/usb/esd_usb.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 1430edf8898386..253cb2a50a5173 100644
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -1151,10 +1151,13 @@ static void esd_usb2_disconnect(struct usb_interface *intf)
 			if (dev->nets[i]) {
 				netdev = dev->nets[i]->netdev;
 				unregister_netdev(netdev);
-				free_candev(netdev);
 			}
 		}
 		unlink_all_urbs(dev);
+		for (i = 0; i < dev->net_count; i++) {
+			if (dev->nets[i])
+				free_candev(dev->nets[i]->netdev);
+		}
 		kfree(dev);
 	}
 }
-- 
2.53.0