Re: [PATCH 1/4] uacce: fix for cdev memory leak

[huangchenghai <huangchenghai2@huawei.com>]

On Thu, Aug 22, 2025 at 07:27 PM +0800, Greg KH wrote:
> On Fri, Aug 22, 2025 at 06:39:01PM +0800, Chenghai Huang wrote:
>> From: Wenkai Lin <linwenkai6@hisilicon.com>
>>
>> If adding uacce cdev to the system fails, it could be due to two
>> reasons: either the device's devt exists when the failure occurs,
>> or the device_add operation fails. In the latter case, cdev_del
>> will be executed, but in the former case, it will not, leading to a
>> resource leak. Therefore, it is necessary to perform the cdev_del
>> action during abnormal exit.
>>
>> Fixes: 015d239ac014 ("uacce: add uacce driver")
>> Signed-off-by: Wenkai Lin <linwenkai6@hisilicon.com>
>> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
>> ---
>>   drivers/misc/uacce/uacce.c | 11 ++++++++++-
>>   1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
>> index 42e7d2a2a90c..3604f722ed60 100644
>> --- a/drivers/misc/uacce/uacce.c
>> +++ b/drivers/misc/uacce/uacce.c
>> @@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(uacce_alloc);
>>    */
>>   int uacce_register(struct uacce_device *uacce)
>>   {
>> +	int ret;
>> +
>>   	if (!uacce)
>>   		return -ENODEV;
>>   
>> @@ -529,7 +531,14 @@ int uacce_register(struct uacce_device *uacce)
>>   	uacce->cdev->ops = &uacce_fops;
>>   	uacce->cdev->owner = THIS_MODULE;
>>   
>> -	return cdev_device_add(uacce->cdev, &uacce->dev);
>> +	ret = cdev_device_add(uacce->cdev, &uacce->dev);
>> +	if (ret) {
>> +		cdev_del(uacce->cdev);
>> +		uacce->cdev = NULL;
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>>   }
>>   EXPORT_SYMBOL_GPL(uacce_register);
>>   
>> -- 
>> 2.33.0
>>
> Hi,
>
> This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
> a patch that has triggered this response.  He used to manually respond
> to these common problems, but in order to save his sanity (he kept
> writing the same thing over and over, yet to different people), I was
> created.  Hopefully you will not take offence and will fix the problem
> in your patch and resubmit it so that it can be accepted into the Linux
> kernel tree.
>
> You are receiving this message because of the following common error(s)
> as indicated below:
>
> - You have marked a patch with a "Fixes:" tag for a commit that is in an
>    older released kernel, yet you do not have a cc: stable line in the
>    signed-off-by area at all, which means that the patch will not be
>    applied to any older kernel releases.  To properly fix this, please
>    follow the documented rules in the
>    Documentation/process/stable-kernel-rules.rst file for how to resolve
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>
> If you wish to discuss this problem further, or you have questions about
> how to resolve this issue, please feel free to respond to this email and
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>
> thanks,
>
> greg k-h's patch email bot
Okay，I will add it in v2.

Thanks,
ChengHai