> -----Original Message-----
> From: Jakub Kicinski <[email protected]>
> Sent: Wednesday, June 7, 2023 10:01 PM
> To: Simon Wunderlich <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]
> mesh.org; Vladislav Efanov <[email protected]>; [email protected]; Sven
> Eckelmann <[email protected]>
> Subject: Re: [PATCH 1/1] batman-adv: Broken sync while rescheduling delayed
> work
>
> On Wed, 7 Jun 2023 17:55:15 +0200 Simon Wunderlich wrote:
> > The reason for these issues is the lack of synchronization. Delayed
> > work (batadv_dat_purge) schedules new timer/work while the device
> > is being deleted. As the result new timer/delayed work is set after
> > cancel_delayed_work_sync() was called. So after the device is freed
> > the timer list contains pointer to already freed memory.
>
> I guess this is better than status quo but is the fix really complete?
> We're still not preventing the timer / work from getting scheduled
> and staying alive after the netdev has been freed, right?
Yea, I would expect some synchronization mechanism to ensure that after
cancel_delayed_work_sync() you can't queue the work again.
I know for timers there is recently timer_shutdown_sync() which can be used to
guarantee a timer can't re-arm at all, and its intended for some situations
where there is a cyclic dependency...
Thanks,
Jake
