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Message-ID: <0f33ea7f-d0a4-bc39-1d26-02518fa460a4@quicinc.com>
Date:   Fri, 5 May 2023 14:51:31 +0530
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Subject: Re: [PATCH v5] usb: gadget: u_serial: Add null pointer check in
 gserial_resume
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To:     Alan Stern <stern@rowland.harvard.edu>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Xiu Jianfeng <xiujianfeng@huawei.com>,
        Pratham Pratap <quic_ppratap@quicinc.com>,
        Jack Pham <quic_jackp@quicinc.com>,
        <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <1676309438-14922-1-git-send-email-quic_prashk@quicinc.com>
 <Y+p6TUBtikbmnTGe@rowland.harvard.edu>
From:   Prashanth K <quic_prashk@quicinc.com>
In-Reply-To: <Y+p6TUBtikbmnTGe@rowland.harvard.edu>
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On 13-02-23 11:28 pm, Alan Stern wrote:
> On Mon, Feb 13, 2023 at 11:00:38PM +0530, Prashanth K wrote:
>> Consider a case where gserial_disconnect has already cleared
>> gser->ioport. And if a wakeup interrupt triggers afterwards,
>> gserial_resume gets called, which will lead to accessing of
>> gser->ioport and thus causing null pointer dereference.Add
>> a null pointer check to prevent this.
>>
>> Added a static spinlock to prevent gser->ioport from becoming
>> null after the newly added check.
>>
>> Fixes: aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume callbacks")
>> Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
>> ---
>> v5: Updated the comment in new patch
> 
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> 
> I'm not very familiar with the u_serial function.  Is it possible for
> gserial_disconnect to cause a similar problem in gserial_suspend?
> 
> Alan Stern
> 
Hi Alen,

You were right, we have similar issue in suspend path also. I have 
pushed a patch for the same.

Regards,
Prashanth K