Re: [PATCH v2] USB: ohci-nxp: Fix error handling in ohci-hcd-nxp driver

Vladimir Zapolskiy
2025-11-17T19:44:57Z

On 11/17/25 16:56, Alan Stern wrote:
> On Mon, Nov 17, 2025 at 09:53:21AM +0100, Arnd Bergmann wrote:
>> On Mon, Nov 17, 2025, at 02:34, Ma Ke wrote:
>>> When obtaining the ISP1301 I2C client through the device tree, the
>>> driver does not release the device reference in the probe failure path
>>> or in the remove function. This could cause a reference count leak,
>>> which may prevent the device from being properly unbound or freed,
>>> leading to resource leakage.
>>>
>>> Fix this by storing whether the client was obtained via device tree
>>> and only releasing the reference in that case.
>>>
>>> Found by code review.
>>>
>>> Cc: stable@vger.kernel.org
>>> Fixes: 73108aa90cbf ("USB: ohci-nxp: Use isp1301 driver")
>>> Signed-off-by: Ma Ke <make24@iscas.ac.cn>
>>
>> The patch looks fine in principle, however I don't see any way
>> this driver would be probed without devicetree, and I think
>> it would be better to remove all the traces of the pre-DT
>> logic in it.
>>
>> The lpc32xx platform was converted to DT back in 2012, so
>> any reference to the old variant is dead code. Something like
>> the patch below should work here.
>>
>> Other thoughts on this driver, though I I'm not sure anyone
>> is going to have the energy to implement these:
>>
>> - the reference to isp1301_i2c_client should be kept in
>> the hcd private data, after allocating a structure, by
>> setting driver->hcd_priv_size.
>> - instead of looking for the i2c device, I would suppose
>> it should look for a usb_phy instead, as there is no
>> guarantee on the initialization being ordered at the
>> moment.
>> - instead of a usb_phy, the driver should probably use
>> a generic phy (a much larger rework).

Since I'm one of the remaining users and holders of the LPC32xx powered
boards, I should take this task.

>
> Considering what the comments at the start of the file say:
>
> * Currently supported OHCI host devices:
> * - NXP LPC32xx
>
> * NOTE: This driver does not have suspend/resume functionality
> * This driver is intended for engineering development purposes only
>
> I wonder whether any existing systems actually use this driver.
>

The LPC32xx OHCI host device works fine with the driver, noteworthy
there were some issues with the LPC32xx UDC though.

Any pre-dt leftovers should be removed from the driver, as Arnd suggested.

--
Best wishes,
Vladimir