linux-kernel - [PATCH net v3] net: usb: Remove disruptive netif_wake_queue in rtl8150_set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250924134350.264597-1-viswanathiyyappan@gmail.com>
Date: Wed, 24 Sep 2025 19:13:50 +0530
From: I Viswanath <viswanathiyyappan@...il.com>
To: kuba@...nel.org,
	michal.pecio@...il.com,
	edumazet@...gle.com,
	andrew+netdev@...n.ch,
	davem@...emloft.net,
	petkan@...leusys.com,
	pabeni@...hat.com
Cc: linux-usb@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	skhan@...uxfoundation.org,
	linux-kernel-mentees@...ts.linux.dev,
	david.hunter.linux@...il.com,
	I Viswanath <viswanathiyyappan@...il.com>,
	syzbot+78cae3f37c62ad092caa@...kaller.appspotmail.com
Subject: [PATCH net v3] 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@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=78cae3f37c62ad092caa
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-by: Michal Pecio <michal.pecio@...il.com>
Signed-off-by: I Viswanath <viswanathiyyappan@...il.com>
---
v1: 
Link: https://lore.kernel.org/netdev/20250920045059.48400-1-viswanathiyyappan@gmail.com/
 
v2:
- Add explanation why netif_stop_queue/netif_wake_queue can be safely removed
- Add the net prefix to the patch, designating it to the net tree
Link: https://lore.kernel.org/netdev/20250920181852.18164-1-viswanathiyyappan@gmail.com/
 
v3:
- Simplified the event sequence that lead to the warning
- Added Tested-by tag

 drivers/net/usb/rtl8150.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
index ddff6f19ff98..92add3daadbb 100644
--- 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,
-- 
2.47.3