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SubjectRe: [patch V3 17/17] Bluetooth: hci_qca: Fix the teardown problem for real
On Wed, 23 Nov 2022, Thomas Gleixner wrote:

> While discussing solutions for the teardown problem which results from
> circular dependencies between timers and workqueues, where timers schedule
> work from their timer callback and workqueues arm the timers from work
> items, it was discovered that the recent fix to the QCA code is incorrect.
>
> That commit fixes the obvious problem of using del_timer() instead of
> del_timer_sync() and reorders the teardown calls to
>
> destroy_workqueue(wq);
> del_timer_sync(t);
>
> This makes it less likely to explode, but it's still broken:
>
> destroy_workqueue(wq);
> /* After this point @wq cannot be touched anymore */
>
> ---> timer expires
> queue_work(wq) <---- Results in a NULl pointer dereference

The last NIT (for now...): s/NULl/NULL

Thanks,

Anna-Maria

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