From: Johan Hovold <johan@kernel.org>
To: Wentao Liang <vulab@iscas.ac.cn>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] USB: usb_wwan: Fix urb leak in usb_wwan_close()
Date: Thu, 17 Sep 2026 11:04:19 +0200 [thread overview]
Message-ID: <aqutE84DMjEPuDT-@hovoldconsulting.com> (raw)
In-Reply-To: <20260916165608.2085613-1-vulab@iscas.ac.cn>
On Wed, Sep 16, 2026 at 04:56:08PM +0000, Wentao Liang wrote:
> usb_wwan_close() drains the delayed write urbs with
> usb_get_from_anchor(), which returns the urb with a new reference
> taken. The loop only clears the busy flag of the urb and never drops
> that reference, so each drained urb keeps one reference forever and
> the urb object is not freed when usb_wwan_port_remove() later drops
> the port's own reference.
>
> Drop the reference with usb_put_urb() once the urb has been found in
> the out_urb array by unbusy_queued_urb(), leaving the reference held
> by the port's preallocated out_urbs array.
>
> Fixes: 79eed03e77d4 ("USB: usb_wwan: fix urb leak at shutdown")
> Cc: stable@vger.kernel.org
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Also looks correct, but again, how was this issue found and fixed?
Johan
prev parent reply other threads:[~2026-09-17 9:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-16 16:56 [PATCH] USB: usb_wwan: Fix urb leak in usb_wwan_close() Wentao Liang
2026-09-17 9:04 ` Johan Hovold [this message]
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