Lizhi Xu 9a579d6a39 usbnet: Prevents free active kevent
[ Upstream commit 420c84c330d1688b8c764479e5738bbdbf0a33de ]

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().

Fixes: a69e617e53 ("usbnet: Fix linkwatch use-after-free on disconnect")
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=8bfd7bcc98f7300afb84
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Link: https://patch.msgid.link/20251022024007.1831898-1-lizhi.xu@windriver.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-24 10:29:14 +01:00
2025-11-24 10:29:12 +01:00
2022-09-28 09:02:20 +02:00
2025-11-02 22:14:42 +09:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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