net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast

syzbot reported WARNING in rtl8150_start_xmit/usb_submit_urb.
This is the sequence of events that leads to the warning:

rtl8150_start_xmit() {
	netif_stop_queue();
	usb_submit_urb(dev->tx_urb);
}

rtl8150_set_multicast() {
	netif_stop_queue();
	netif_wake_queue();		<-- wakes up TX queue before URB is done
}

rtl8150_start_xmit() {
	netif_stop_queue();
	usb_submit_urb(dev->tx_urb);	<-- double submission
}

rtl8150_set_multicast being the ndo_set_rx_mode callback should not be
calling netif_stop_queue and notif_start_queue as these handle
TX queue synchronization.

The net core function dev_set_rx_mode handles the synchronization
for rtl8150_set_multicast making it safe to remove these locks.

Reported-and-tested-by: syzbot+78cae3f37c62ad092caa@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=78cae3f37c62ad092caa
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: I Viswanath <viswanathiyyappan@gmail.com>
Link: https://patch.msgid.link/20250924134350.264597-1-viswanathiyyappan@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
index ddff6f19ff98eb5a61c71f4b4fa795aa3f9ec3c0..92add3daadbb1813842033c6b0b5e67cb6b3b52b 100644 (file)
--- a/drivers/net/usb/rtl8150.c
+++ b/drivers/net/usb/rtl8150.c
@@ -664,7 +664,6 @@ static void rtl8150_set_multicast(struct net_device *netdev)
        rtl8150_t *dev = netdev_priv(netdev);
        u16 rx_creg = 0x9e;
 
-       netif_stop_queue(netdev);
        if (netdev->flags & IFF_PROMISC) {
                rx_creg |= 0x0001;
                dev_info(&netdev->dev, "%s: promiscuous mode\n", netdev->name);
@@ -678,7 +677,6 @@ static void rtl8150_set_multicast(struct net_device *netdev)
                rx_creg &= 0x00fc;
        }
        async_set_registers(dev, RCR, sizeof(rx_creg), rx_creg);
-       netif_wake_queue(netdev);
 }
 
 static netdev_tx_t rtl8150_start_xmit(struct sk_buff *skb,