Re: [PATCH] bus: fsl-mc: fix an error handling in fsl_mc_device_add()

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Le 24/12/2025 à 08:54, Dan Carpenter a écrit :
> On Tue, Dec 23, 2025 at 04:34:44PM +0100, Christophe Leroy (CS GROUP) wrote:
>>
>>
>> Le 22/12/2025 à 08:49, Haoxiang Li a écrit :
>>> If device_add() fails, call put_device() to drop the device
>>> reference and do the cleanp.
>>>
>>> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
>>> Closes: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2Fb767348e-d89c-416e-acea-1ebbff3bea20%40stanley.mountain%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cfd3865935a164c2083cc08de42c1b5a5%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639021596902232212%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=j5%2BqptzXvrxcnaaH3PIDorAYMexoPmf3PWi5GbpVD9s%3D&reserved=0
>>> Signed-off-by: Su Hui <suhui@nfschina.com>
>>> Signed-off-by: Haoxiang Li <lihaoxiang@isrc.iscas.ac.cn>
>>> ---
>>>    drivers/bus/fsl-mc/fsl-mc-bus.c | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
>>> index 25845c04e562..90a2107a9905 100644
>>> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
>>> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
>>> @@ -896,7 +896,8 @@ int fsl_mc_device_add(struct fsl_mc_obj_desc *obj_desc,
>>>    		dev_err(parent_dev,
>>>    			"device_add() failed for device %s: %d\n",
>>>    			dev_name(&mc_dev->dev), error);
>>> -		goto error_cleanup_dev;
>>> +		put_device(&mc_dev->dev)
>>
>> This change has obviously not been tested, not even built.
>>
> 
> Yeah, it doesn't build.
> 
>> And by droping the goto, the kfree() are not done anymore, leaking
>> mc_bus/mc_dev p kzalloced areas.
>>
> 
> Calling put_device() triggers fsl_mc_device_release() which does the
> free.

Ok, then this needs to be said in the commit message.

By the way I'm a bit puzzled by the device_add() doc versus the 
put_device(), because it looks like device_add() already calls 
put_device() in its error path, see 
https://elixir.bootlin.com/linux/v6.19-rc2/source/drivers/base/core.c#L3716

> 
> regards,
> dan carpenter
> 
>>> +		return error;
>>>    	}
>>>    	dev_dbg(parent_dev, "added %s\n", dev_name(&mc_dev->dev));