linux-kernel - Re: Re: [PATCH] thermal/int340x_thermal: Check for null pointer after calling kmemdup

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Message-Id: <20220107143230.4057632-1-jiasheng@iscas.ac.cn>
Date:   Fri,  7 Jan 2022 22:32:30 +0800
From:   Jiasheng Jiang <jiasheng@...as.ac.cn>
To:     daniel.lezcano@...aro.org, rui.zhang@...el.com, amitk@...nel.org
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jiasheng Jiang <jiasheng@...as.ac.cn>
Subject: Re: Re: [PATCH] thermal/int340x_thermal: Check for null pointer after calling kmemdup

On Fri, Jan 07, 2022 at 08:05:17PM +0800, Daniel Lezcano wrote:
>> diff --git a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
>> index 823354a1a91a..999b5682c28a 100644
>> --- a/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
>> +++ b/drivers/thermal/intel/int340x_thermal/int3400_thermal.c
>> @@ -462,6 +462,11 @@ static void int3400_setup_gddv(struct int3400_thermal_priv *priv)
>>  	priv->data_vault = kmemdup(obj->package.elements[0].buffer.pointer,
>>  				   obj->package.elements[0].buffer.length,
>>  				   GFP_KERNEL);
>> +	if (!priv->data_vault) {
>> +		kfree(buffer.pointer);
>> +		return;
>> +	}
>> +
>
> There is another kfree on error before
>
> Please replace those by a goto out_kfree;
>
>>  	bin_attr_data_vault.private = priv->data_vault;
>>  	bin_attr_data_vault.size = obj->package.elements[0].buffer.length;
>
> out_kfree;
>>  	kfree(buffer.pointer);
>> 

Ok, I will submit new patch to replace those.

> Why there is no error code returned to the caller?

Well, I check the commit 0ba13c763aac ("thermal/int340x_thermal: Export GDDV")
and find that it was designed to return without error.
And it seems that the 'bin_attr_data_vault.size' is related to the
'bin_attr_data_vault.private'.
If the size is 0, then the array will not be used.
Therefore, I think it is unnecessary to return error.

Sincerely thanks,
Jiang