linux-kernel - Re: [PATCH V2 2/2] clocksource: imx-gpt: add necessary kfree to avoid resource leak

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Message-ID: <d811ef14-ec53-3422-b747-7df0c1ce360d@linaro.org>
Date:   Tue, 6 Nov 2018 10:06:03 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Anson Huang <anson.huang@....com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH V2 2/2] clocksource: imx-gpt: add necessary kfree to avoid
 resource leak


Hi Anson,

On 06/11/2018 02:38, Anson Huang wrote:
> Hi, Daniel
> 
> Best Regards!
> Anson Huang
> 
>> -----Original Message-----
>> From: Daniel Lezcano [mailto:daniel.lezcano@...aro.org]
>> Sent: 2018年11月5日 21:35
>> To: Anson Huang <anson.huang@....com>; tglx@...utronix.de;
>> linux-kernel@...r.kernel.org
>> Cc: dl-linux-imx <linux-imx@....com>
>> Subject: Re: [PATCH V2 2/2] clocksource: imx-gpt: add necessary kfree to avoid
>> resource leak
>>
>> Hi Anson,
>>
>> On 05/11/2018 02:10, Anson Huang wrote:
>>> kfree should be called to free resource in error path before return.
>>>
>>> Signed-off-by: Anson Huang <Anson.Huang@....com>
>>> ---
>>>  drivers/clocksource/timer-imx-gpt.c | 8 ++++++--
>>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/clocksource/timer-imx-gpt.c
>>> b/drivers/clocksource/timer-imx-gpt.c
>>> index a3d6ccb..0f78b30 100644
>>> --- a/drivers/clocksource/timer-imx-gpt.c
>>> +++ b/drivers/clocksource/timer-imx-gpt.c
>>> @@ -477,12 +477,16 @@ static int __init mxc_timer_init_dt(struct
>> device_node *np,  enum imx_gpt_type t
>>>  		return -ENOMEM;
>>>
>>>  	imxtm->base = of_iomap(np, 0);
>>> -	if (!imxtm->base)
>>> +	if (!imxtm->base) {
>>> +		kfree(imxtm);
>>>  		return -ENXIO;
>>> +	}
>>>
>>>  	imxtm->irq = irq_of_parse_and_map(np, 0);
>>> -	if (imxtm->irq <= 0)
>>> +	if (imxtm->irq <= 0) {
>>> +		kfree(imxtm);
>>>  		return -EINVAL;
>>> +	}
>>>
>>>  	imxtm->clk_ipg = of_clk_get_by_name(np, "ipg");
>>
>> Please convert to timer-of API.
> 
> This patch mainly to fix the potential resource leak issue, for converting
> to timer-of API, should I add another patch for it? Since it is a different
> subject.

Actually I was unclear. The patch is duplicating the kfree in the error
path, usually a rollback routine should be provided.

So instead of creating this rollback path, you can directly use the
timer-of which contains the error check and rollback.



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