Re: [PATCH v1 05/12] usb: otg-fsm: Fix hrtimer list corruption

[Dmitry Osipenko]

09.07.2021 01:42, Michał Mirosław пишет:
> On Thu, Jul 01, 2021 at 05:23:58AM +0300, Dmitry Osipenko wrote:
>> The HNP work can be re-scheduled while it's still in-fly. This results in
>> re-initialization of the busy work, resetting the hrtimer's list node of
>> the work and crashing kernel with null dereference within kernel/timer
>> once work's timer is expired. It's very easy to trigger this problem by
>> re-plugging USB cable quickly. Initialize HNP work only once to fix this
>> trouble.
> [...]
>> -	INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
>> +	if (!fsm->hnp_work_inited) {
>> +		INIT_DELAYED_WORK(&fsm->hnp_polling_work, otg_hnp_polling_work);
>> +		fsm->hnp_work_inited = true;
>> +	}
>> +
> 
> Maybe you could just add an initialization function to be called by
> users of otg_fsm? It seems that only chipidea driver uses this
> struct currently.

If there are any out-of-tree users of the OTG FSM, then they will all
get the fix too using the universal solution.