Sven,
cancel_delayed_work_sync() and queue_delayed_work()
use WORK_STRUCT_PENDING_BIT in work->data to synchronize.
INIT_DELAYED_WORK() clears this bit.
The situation is : __cancel_work_timer() sets WORK_STRUCT_PENDING_BIT
but INIT_DELAYED_WORK() in batadv_dat_start_timer() clears it
and queue_delayed_work() schedules new work.
Best regards,
Vlad.
On 26.05.2023 19:49, Sven Eckelmann wrote:
On Friday, 26 May 2023 18:16:32 CEST Vladislav Efanov 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.
You are most likely right but could you please point out what in the worker is checked by the workqueue code that prevents it from being scheduled again? (and which seems to be overwritten as your patch seems to suggest)
I think __cancel_work_timer marked the work as canceling but batadv_dat_start_timer reinitialized the worked (thus removing this important state). Would be nice if you could either correct me or confirm what I think to remember.
Kind regards, Sven