netdev - Re: [PATCH V2] usbnet: Prevents free active kevent

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Message-ID: <20251017152731.4bb7f1f9@kernel.org>
Date: Fri, 17 Oct 2025 15:27:31 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Lizhi Xu <lizhi.xu@...driver.com>
Cc: <ahmed.zaki@...el.com>, <aleksander.lobakin@...el.com>,
 <davem@...emloft.net>, <edumazet@...gle.com>, <horms@...nel.org>,
 <kuniyu@...zon.com>, <linux-kernel@...r.kernel.org>,
 <netdev@...r.kernel.org>, <pabeni@...hat.com>, <samsun1006219@...il.com>,
 <sdf@...ichev.me>, <syzkaller-bugs@...glegroups.com>,
 <syzkaller@...glegroups.com>
Subject: Re: [PATCH V2] usbnet: Prevents free active kevent

On Fri, 17 Oct 2025 17:05:41 +0800 Lizhi Xu wrote:
> The root cause of this issue are:
> 1. When probing the usbnet device, executing usbnet_link_change(dev, 0, 0);
> put the kevent work in global workqueue. However, the kevent has not yet
> been scheduled when the usbnet device is unregistered. Therefore, executing
> free_netdev() results in the "free active object (kevent)" error reported
> here.
> 
> 2. Another factor is that when calling usbnet_disconnect()->unregister_netdev(),
> if the usbnet device is up, ndo_stop() is executed to cancel the kevent.
> However, because the device is not up, ndo_stop() is not executed.
> 
> The solution to this problem is to cancel the kevent before executing
> free_netdev(), which also deletes the delay timer.

Please add a fixes tag, and repost.
Please don't send new versions in reply to previous / existing threads.
Please read at least the tl;dr of:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
-- 
pw-bot: cr