Re: [PATCH 5.10] staging: gasket: interrupt: Clean interrupt_data after free

Ekaterina Esina
2023-05-16T10:44:12Z

On 15.05.2023 16:02, Greg Kroah-Hartman wrote:
> On Mon, May 15, 2023 at 03:29:50PM +0300, Esina Ekaterina wrote:
>> Add interrupt_data = NULL after kfree(interrupt_data) in
>> gasket_interrupt_init. It is needed to avoid double free
>> in gasket_interrupt_cleanup, there is a check for NULL
>> before kfree(interrupt_data).
>>
>> Found by Astra Linux on behalf of Linux Verification Center
>> (linuxtesting.org) with SVACE.
>>
>> Fixes: 9a69f5087ccc ("drivers/staging: Gasket driver framework + Apex driver")
>> Signed-off-by: Esina Ekaterina <eesina@astralinux.ru>
>> ---
>> drivers/staging/gasket/gasket_interrupt.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
>> index 864342acfd86..48b664b9134a 100644
>> --- a/drivers/staging/gasket/gasket_interrupt.c
>> +++ b/drivers/staging/gasket/gasket_interrupt.c
>> @@ -337,6 +337,7 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>> sizeof(*interrupt_data->eventfd_ctxs), GFP_KERNEL);
>> if (!interrupt_data->eventfd_ctxs) {
>> kfree(interrupt_data);
>> + interrupt_data = NULL;
>> return -ENOMEM;
>> }
>>
>> @@ -346,6 +347,7 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>> if (!interrupt_data->interrupt_counts) {
>> kfree(interrupt_data->eventfd_ctxs);
>> kfree(interrupt_data);
>> + interrupt_data = NULL;
>> return -ENOMEM;
>> }
>>
>> --
>> 2.40.1
>
> Also, your tool is wrong, this is not a correct fix at all.
>
> How did you test it? Why is your tool spitting out incorrect code? Why
> are you not verifying it's output before asking others to do so?
>
> Please don't do this anymore, it's wasteful on our side, right? Please
> take the time to review existing changes for problems, that would be
> more useful overall to everyone.
>
> thanks,
>
> greg k-h

I apologize, there is a mistake. It should've been
gasket_dev->interrupt_data = NULL istead of interrupt_data = NULL

Best regards,
Ekaterina Esina