From: Johan Hovold <johan@kernel.org>
To: Deepanshu Kartikey <kartikey406@gmail.com>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot+5fabc1ae99ff40690d84@syzkaller.appspotmail.com
Subject: Re: [PATCH] USB: serial: keyspan: fix use-after-free in keyspan_close
Date: Thu, 10 Sep 2026 14:54:28 +0200 [thread overview]
Message-ID: <aqKohDTyqN_MGKSf@hovoldconsulting.com> (raw)
In-Reply-To: <20260831023701.9579-1-kartikey406@gmail.com>
On Mon, Aug 31, 2026 at 08:07:01AM +0530, Deepanshu Kartikey wrote:
> keyspan_port_remove() frees the port's private data (p_priv) while
> keyspan_close() may still be running concurrently on another task,
> e.g. triggered by an explicit TIOCVHANGUP ioctl on an already-open
> tty racing with device disconnect. This results in keyspan_close()
> dereferencing freed memory.
>
> Fix this by adding a mutex to keyspan_serial_private that serializes
> keyspan_close() against keyspan_port_remove(): the latter clears the
> port's private data pointer under the lock before freeing it, and
> the former re-fetches and checks that pointer under the same lock
> before use.
>
> Reported-by: syzbot+5fabc1ae99ff40690d84@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=5fabc1ae99ff40690d84
This isn't a driver specific issue. I've just sent a fix for the tty
port implementation here:
https://lore.kernel.org/r/20260910125114.640880-1-johan@kernel.org
Johan
prev parent reply other threads:[~2026-09-10 12:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-31 2:37 Deepanshu Kartikey
2026-09-10 12:54 ` Johan Hovold [this message]
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