Re: [PATCH] i2c: core: Fix possible memleak in i2c_new_client_device()

Yang Yingliang
2021-10-18T03:03:30Z

Hi,

On 2021/10/17 23:27, Wolfram Sang wrote:
>> In error path after calling i2c_dev_set_name(), the put_device()
>> should be used to give up the device reference, then the name
>> allocated in dev_set_name() will be freed in kobject_cleanup().
> I don't see it. dev_set_name does not call device_get, so why should we
> call device_put on failure? No other user of dev_set_name seems to do
> this. So, if this is an imbalance, where does the unmatched get_device
> really come from?
The reference is initialized in device_initialize() called in
device_register(), if device_register()
fails, the 'kobj->name' is leaked.

Thanks,
Yang
>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>> drivers/i2c/i2c-core-base.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
>> index 54964fbe3f03..190d4fd5e594 100644
>> --- a/drivers/i2c/i2c-core-base.c
>> +++ b/drivers/i2c/i2c-core-base.c
>> @@ -1047,8 +1047,6 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
>> client->dev.of_node = of_node_get(info->of_node);
>> client->dev.fwnode = info->fwnode;
>>
>> - i2c_dev_set_name(adap, client, info);
>> -
>> if (info->swnode) {
>> status = device_add_software_node(&client->dev, info->swnode);
>> if (status) {
>> @@ -1059,17 +1057,20 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
>> }
>> }
>>
>> + i2c_dev_set_name(adap, client, info);
>> status = device_register(&client->dev);
>> - if (status)
>> - goto out_remove_swnode;
>> + if (status) {
>> + device_remove_software_node(&client->dev);
>> + of_node_put(info->of_node);
>> + put_device(&client->dev);
>> + return ERR_PTR(status);
>> + }
>>
>> dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
>> client->name, dev_name(&client->dev));
>>
>> return client;
>>
>> -out_remove_swnode:
>> - device_remove_software_node(&client->dev);
>> out_err_put_of_node:
>> of_node_put(info->of_node);
>> out_err:
>> --
>> 2.25.1
>>