Re: [PATCH] ieee802154: ca8210: Add missing check for kfifo_alloc() in ca8210_probe()

On 04/11/2024 13:12, Simon Horman wrote:
> + Marcel
> 
> On Tue, Oct 29, 2024 at 07:27:12PM +0100, Keisuke Nishimura wrote:
>> ca8210_test_interface_init() returns the result of kfifo_alloc(),
>> which can be non-zero in case of an error. The caller, ca8210_probe(),
>> should check the return value and do error-handling if it fails.
>>
>> Fixes: ded845a781a5 ("ieee802154: Add CA8210 IEEE 802.15.4 device driver")
>> Signed-off-by: Keisuke Nishimura <[email protected]>
>> ---
>>   drivers/net/ieee802154/ca8210.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
>> index e685a7f946f0..753215ebc67c 100644
>> --- a/drivers/net/ieee802154/ca8210.c
>> +++ b/drivers/net/ieee802154/ca8210.c
>> @@ -3072,7 +3072,11 @@ static int ca8210_probe(struct spi_device *spi_device)
>>   	spi_set_drvdata(priv->spi, priv);
>>   	if (IS_ENABLED(CONFIG_IEEE802154_CA8210_DEBUGFS)) {
>>   		cascoda_api_upstream = ca8210_test_int_driver_write;
>> -		ca8210_test_interface_init(priv);
>> +		ret = ca8210_test_interface_init(priv);
>> +		if (ret) {
>> +			dev_crit(&spi_device->dev, "ca8210_test_interface_init failed\n");
>> +			goto error;
> 
> Hi Nishimura-san,
> 
> I see that this will conditionally call kfifo_free().
> Is that safe here? And in branches to error above this point?
> 

Hi Horman-san,

Thank you for taking a look at this patch.

> Is that safe here?

Yes, it is safe. The failure of kfifo_alloc(&test->up_fifo,
CA8210_TEST_INT_FIFO_SIZE, GFP_KERNEL) sets test->up_fifo.data to NULL,
and kfifo_free() will then do kfree(test->up_fifo.data) with some minor
clean-up.

> And in branches to error above this point?

Are you referring to the error handling for ieee802154_alloc_hw()? To my
understanding, since spi_get_drvdata() in ca8210_remove() returns NULL
if there's an error, we shouldn’t need to call
ca8210_test_interface_clear(). However, I’m not familiar with this code,
so please correct me if I'm mistaken.

best,
Keisuke

>> +		}
>>   	} else {
>>   		cascoda_api_upstream = NULL;
>>   	}
>> -- 
>> 2.34.1
>>
>>