Hello, On Sat, Jul 21, 2018 at 10:44:09PM -0700, David Miller wrote: > 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.
Do you think that there is still a problem? When free_irq() for the external visible irq returns the muxed irqs should be all gone, too, so this should not trigger, should it? > 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. Yes. > Applied and queued up for -stable, thanks. Fine, thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
