From: Uwe Kleine-König <u.kleine-koe...@pengutronix.de> Date: Fri, 20 Jul 2018 11:53:15 +0200
> free_irq() waits until all handlers for this IRQ have completed. As the > relevant handler (mv88e6xxx_g1_irq_thread_fn()) takes the chip's reg_lock > it might never return if the thread calling free_irq() holds this lock. > > For the same reason kthread_cancel_delayed_work_sync() in the polling case > must not hold this lock. > > Also first free the irq (or stop the worker respectively) such that > mv88e6xxx_g1_irq_thread_work() isn't called any more before the irq > mappings are dropped in mv88e6xxx_g1_irq_free_common() to prevent the > worker thread to call handle_nested_irq(0) which results in a NULL-pointer > exception. > > Signed-off-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de> Looks good. Note than the IRQ domain unmapping will do a synchronize_irq() which should cause the same deadlock as free_irq() will with the reg_lock held. Note also that g2 IRQ freeing gets the ordering right, and doesn't need a lock because it doesn't program any registers when tearing down it's IRQ. Applied and queued up for -stable, thanks.
