Re: [PATCH] HID: axff: add cleanup allocated struct axff_device heap

[Jeongjun Park]

Hello Dmitry,

Dmitry Torokhov wrote:
> Hi Jeongjun,
> 
> On Tue, Aug 19, 2025 at 12:43:02AM +0900, Jeongjun Park wrote:
> > Currently, acrux hid driver allocates heap memory equal to
> > sizeof(struct axff_device) to support force feedback, but there's no code
> > to free this memory except when initialization fails. This causes the
> > allocated memory to not be freed even if the driver is detached.
> > 
> > Therefore, to properly clean up and safely manage the allocated heap,
> > must be modified to use devm_kzalloc().
> 
> You have not tested this, have you? The private data that is passed to
> input_ff_create_memless() is freed by ml_ff_destroy() which is invoked
> when input core calls input_ff_destroy() as part of input device
> teardown. Your change introduces double-free. 

Oops, I checked again and realized my patch was a complete mess.

Thanks for letting me know!

Regards,
Jeongjun Park