linux-kernel - RE: [PATCH] net: usb: r8152: fix transmit queue timeout

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

Message-ID: <ae7e8fc22fcf415d9eb5e4d36ed74231@realtek.com>
Date: Mon, 19 Jan 2026 02:51:31 +0000
From: Hayes Wang <hayeswang@...ltek.com>
To: lu lu <insyelu@...il.com>
CC: "andrew+netdev@...n.ch" <andrew+netdev@...n.ch>,
        "davem@...emloft.net"
	<davem@...emloft.net>,
        nic_swsd <nic_swsd@...ltek.com>, "tiwai@...e.de"
	<tiwai@...e.de>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] net: usb: r8152: fix transmit queue timeout

Original Message-----
> From: lu lu <insyelu@...il.com>
[...]
> if (netif_queue_stopped(tp->netdev)) {
>     if (skb_queue_len(&tp->tx_queue) < tp->tx_qlen)
>         netif_wake_queue(tp->netdev);
>     else
>         netif_trans_update(tp->netdev);
> }
> The first time xmit stops the transmit queue, the queue is not full,
> and it is successfully woken up afterward — OK.
> The second time xmit stops the transmit queue, the network watchdog
> times out immediately because the transmit timestamp was not refreshed
> when the queue was last resumed — FAIL.
> This scenario is logically possible.

This situation should not happen, because trans_start is also updated when the driver stops the TX queue.

https://elixir.bootlin.com/linux/v6.18.6/source/include/linux/netdevice.h#L3629

A TX timeout occurs only if the TX queue has been stopped for longer than RTL8152_TX_TIMEOUT.
It should not occur immediately when the driver stops the TX queue.

Therefore, what needs to be done is to update the timestamp when the TX queue is stopped.
Updating trans_start while the TX queue is not stopped is useless.

Best Regards,
Hayes