kaweth_set_rx_mode(), the ndo_set_rx_mode callback, calls
netif_stop_queue() and netif_wake_queue(). These are TX queue flow
control functions unrelated to RX multicast configuration.

The premature netif_wake_queue() can re-enable TX while tx_urb is still
in-flight, leading to a double usb_submit_urb() on the same URB:

kaweth_start_xmit() {
    netif_stop_queue();
    usb_submit_urb(kaweth->tx_urb);
}

kaweth_set_rx_mode() {
    netif_stop_queue();
    netif_wake_queue();             // wakes TX queue before URB is done
}

kaweth_start_xmit() {
    netif_stop_queue();
    usb_submit_urb(kaweth->tx_urb); // URB submitted while active
}

This triggers the WARN in usb_submit_urb():

  "URB submitted while active"

This is a similar class of bug fixed in rtl8150 by 
commit 958baf5eaee3 ("net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast")

Signed-off-by: Ziyi Guo <n7l8m4@u.northwestern.edu>
---
 drivers/net/usb/kaweth.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/net/usb/kaweth.c b/drivers/net/usb/kaweth.c
index c9efb7df892e..406d1bd070fa 100644
--- a/drivers/net/usb/kaweth.c
+++ b/drivers/net/usb/kaweth.c
@@ -765,8 +765,6 @@ static void kaweth_set_rx_mode(struct net_device *net)
 
 	netdev_dbg(net, "Setting Rx mode to %d\n", packet_filter_bitmap);
 
-	netif_stop_queue(net);
-
 	if (net->flags & IFF_PROMISC) {
 		packet_filter_bitmap |= KAWETH_PACKET_FILTER_PROMISCUOUS;
 	}
@@ -775,7 +773,6 @@ static void kaweth_set_rx_mode(struct net_device *net)
 	}
 
 	kaweth->packet_filter_bitmap = packet_filter_bitmap;
-	netif_wake_queue(net);
 }
 
 /****************************************************************
-- 
2.34.1