Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Sender: linyyuan=codeaurora.org@mg.codeaurora.org
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Sun, 20 Jun 2021 11:46:33 +0800
From:   linyyuan@codeaurora.org
To:     Alan Stern <stern@rowland.harvard.edu>
Cc:     Felipe Balbi <balbi@kernel.org>,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jack Pham <jackp@codeaurora.org>
Subject: Re: [PATCH v3 1/2] usb: udc: core: hide struct usb_gadget_driver to
 gadget driver
In-Reply-To: <20210620021337.GA361976@rowland.harvard.edu>
References: <20210619154309.52127-1-linyyuan@codeaurora.org>
 <20210619154309.52127-2-linyyuan@codeaurora.org>
 <20210620021337.GA361976@rowland.harvard.edu>
Message-ID: <42b3ebc2316495328e2d0061af81ef17@codeaurora.org>
User-Agent: Roundcube Webmail/1.3.9
Precedence: bulk

On 2021-06-20 10:13, Alan Stern wrote:
> On Sat, Jun 19, 2021 at 11:43:08PM +0800, Linyu Yuan wrote:
>> currently most gadget driver have a pointer to save
>> struct usb_gadget_driver from upper layer,
>> it allow upper layer set and unset of the pointer.
>> 
>> there is race that upper layer unset the pointer first,
>> but gadget driver use the pointer later,
>> and it cause system crash due to NULL pointer access.
> 
> This race has already been fixed in Greg's usb-next branch.  See commit
> 7dc0c55e9f30 ("USB: UDC core: Add udc_async_callbacks gadget op") and
> following commits 04145a03db9d ("USB: UDC: Implement
> udc_async_callbacks in dummy-hcd") and b42e8090ba93 ("USB: UDC:
> Implement udc_async_callbacks in net2280").
> 
thanks, this is better, lower driver only need change several places.
> You just need to write a corresponding patch implementing the
> async_callbacks op for dwc3.
yes, i will do.
> 
> Alan Stern