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Subject: Re: [PATCH] net: phy: phy_led_triggers: Fix a possible null-pointer
 dereference in phy_led_trigger_change_speed()
To:     David Miller <davem@davemloft.net>, andrew@lunn.ch
Cc:     f.fainelli@gmail.com, hkallweit1@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20190729134553.GC4110@lunn.ch>
 <f603f3c3-f7c9-8dff-5f30-74174282819c@gmail.com>
 <20190730033229.GA20628@lunn.ch>
 <20190729.204113.316505378355498068.davem@davemloft.net>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <c41475ec-b418-7874-9150-3a6eef125365@gmail.com>
Date:   Tue, 30 Jul 2019 16:03:02 +0800
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On 2019/7/30 11:41, David Miller wrote:
> From: Andrew Lunn <andrew@lunn.ch>
> Date: Tue, 30 Jul 2019 05:32:29 +0200
>
>> On Tue, Jul 30, 2019 at 10:25:36AM +0800, Jia-Ju Bai wrote:
>>>
>>> On 2019/7/29 21:45, Andrew Lunn wrote:
>>>> On Mon, Jul 29, 2019 at 05:24:24PM +0800, Jia-Ju Bai wrote:
>>>>> In phy_led_trigger_change_speed(), there is an if statement on line 48
>>>>> to check whether phy->last_triggered is NULL:
>>>>>      if (!phy->last_triggered)
>>>>>
>>>>> When phy->last_triggered is NULL, it is used on line 52:
>>>>>      led_trigger_event(&phy->last_triggered->trigger, LED_OFF);
>>>>>
>>>>> Thus, a possible null-pointer dereference may occur.
>>>>>
>>>>> To fix this bug, led_trigger_event(&phy->last_triggered->trigger,
>>>>> LED_OFF) is called when phy->last_triggered is not NULL.
>>>>>
>>>>> This bug is found by a static analysis tool STCheck written by us.
>>>> Who is 'us'?
>>> Me and my colleague...
>> Well, we can leave it very vague, giving no idea who 'us' is. But
>> often you want to name the company behind it, or the university, or
>> the sponsor, etc.
> I agree, if you are going to mention that there is a tool you should be
> clear exactly who and what organization are behind it

Thanks for the advice.
I will add my organization in the patch.


Best wishes,
Jia-Ju Bai