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Subject: Re: [PATCH] usb: host: xhci_debugfs: Fix a null pointer dereference
 in xhci_debugfs_create_endpoint()
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     mathias.nyman@intel.com, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20190504033748.17964-1-baijiaju1990@gmail.com>
 <20190504063340.GA26311@kroah.com>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <db68433e-d655-217a-4a73-4bb83069addc@gmail.com>
Date:   Sat, 4 May 2019 15:30:53 +0800
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On 2019/5/4 14:33, Greg KH wrote:
> On Sat, May 04, 2019 at 11:37:48AM +0800, Jia-Ju Bai wrote:
>> In xhci_debugfs_create_slot(), kzalloc() can fail and
>> dev->debugfs_private will be NULL.
>> In xhci_debugfs_create_endpoint(), dev->debugfs_private is used without
>> any null-pointer check, and can cause a null pointer dereference.
>>
>> To fix this bug, a null-pointer check is added in
>> xhci_debugfs_create_endpoint().
>>
>> This bug is found by a runtime fuzzing tool named FIZZER written by us.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> Very rare case, but nice fix.  You should put "potential" in your
> subject line as this is something that no one should ever hit :)

Okay, Greg, thanks for this advice :)


Best wishes,
Jia-Ju Bai