gs_usb_disconnect() destroys the channels one by one via
gs_destroy_candev()/free_candev(). gs_can_close() disposes the RX bulk
URBs on the shared parent->rx_submitted anchor only when the last
active channel is closed. With two or more channels up, the earlier
channels are freed while their RX URBs are still submitted, and a
completion in gs_usb_receive_bulk_callback() accesses the freed struct
gs_can and struct net_device.

Fix this by killing the anchored RX URBs in gs_usb_disconnect() before
the first netdev is destroyed, and in the error path of gs_usb_probe()
before the previously created netdevs are destroyed.

usb_kill_anchored_urbs() waits for running completions and a killed URB
completes with -ENOENT, so the completion handler returns without
resubmitting the URB. The kill in gs_can_close() of the last active
channel then operates on an already empty anchor.

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

Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Cc: stable@vger.kernel.org
Co-developed-by: Song Li <songl@zju.edu.cn>
Signed-off-by: Song Li <songl@zju.edu.cn>
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
---
 drivers/net/can/usb/gs_usb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index ec9a7cb..663746d 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -1595,10 +1595,10 @@ static int gs_usb_probe(struct usb_interface *intf,
 
 			/* on failure destroy previously created candevs */
 			icount = i;
+			usb_kill_anchored_urbs(&parent->rx_submitted);
 			for (i = 0; i < icount; i++)
 				gs_destroy_candev(parent->canch[i]);
 
-			usb_kill_anchored_urbs(&parent->rx_submitted);
 			kfree(parent);
 			return rc;
 		}
@@ -1636,6 +1636,8 @@ static void gs_usb_disconnect(struct usb_interface *intf)
 		return;
 	}
 
+	usb_kill_anchored_urbs(&parent->rx_submitted);
+
 	for (i = 0; i < parent->channel_cnt; i++)
 		if (parent->canch[i])
 			gs_destroy_candev(parent->canch[i]);