[PATCH] usb: cdns3: Do not access memory after free

[Marek Vasut]

On 8/14/25 12:45 PM, Andrew Goodbody wrote:
> On 14/08/2025 04:21, Marek Vasut wrote:
>> On 8/13/25 6:30 PM, Andrew Goodbody wrote:
>>> The call to cdns3_gadget_ep_free_request will free priv_req so do the
>>> call to list_del_init which accesses the memory pointed to by priv_req
>>> before the free.
>>>
>>> This issue was found by Smatch.
>>>
>>> Signed-off-by: Andrew Goodbody <andrew.goodbody at linaro.org>
>>> ---
>>>   drivers/usb/cdns3/gadget.c | 4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
>>> index a30c40ef80e..9eaf7e40ab6 100644
>>> --- a/drivers/usb/cdns3/gadget.c
>>> +++ b/drivers/usb/cdns3/gadget.c
>>> @@ -557,10 +557,10 @@ static void cdns3_wa2_remove_old_request(struct 
>>> cdns3_endpoint *priv_ep)
>>>           trace_cdns3_wa2(priv_ep, "removes eldest request");
>>> +        list_del_init(&priv_req->list);
>>>           kfree(priv_req->request.buf);
>>>           cdns3_gadget_ep_free_request(&priv_ep->endpoint,
>>>                            &priv_req->request);
>>> -        list_del_init(&priv_req->list);
>>
>> Shouldn't the kfree() be moved here instead ? 
>> cdns3_gadget_ep_free_request() also accesses priv_req->request .
> 
> No, I do not think so. The kfree frees priv_req->request.buf not 
> priv_req->request so must happen before the call to 
> cdns3_gadget_ep_free_request.
Thank you for clarifying. Please add this into the commit message, 
ideally wait for TI to test this and provide RB, then send V2 so this 
can go in.