-
Josh Cartwright authored
The use of IRQF_ONESHOT when registering an interrupt handler with request_irq() is non-sensical. Not only that, it also prevents the handler from being threaded when it otherwise should be w/ IRQ_FORCED_THREADING is enabled. This causes the following deadlock observed by Sean Nyekjaer on -rt: Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM [..] rt_spin_lock_slowlock from queue_kthread_work queue_kthread_work from sc16is7xx_irq sc16is7xx_irq [sc16is7xx] from handle_irq_event_percpu handle_irq_event_percpu from handle_irq_event handle_irq_event from handle_level_irq handle_level_irq from generic_handle_irq generic_handle_irq from mxc_gpio_irq_handler mxc_gpio_irq_handler from mx3_gpio_irq_handler mx3_gpio_irq_handler from generic_handle_irq generic_handle_irq from __handle_domain_irq __handle_domain_irq from gic_handle_irq gic_handle_irq from __irq_svc __irq_svc from rt_spin_unlock rt_spin_unlock from kthread_worker_fn kthread_worker_fn from kthread kthread from ret_from_fork Fixes: 9e6f4ca3 ("sc16is7xx: use kthread_worker for tx_work and irq") Reported-by:
Sean Nyekjaer <sean.nyekjaer@prevas.dk> Signed-off-by:
Josh Cartwright <joshc@ni.com> Cc: linux-rt-users@vger.kernel.org Cc: Jakub Kicinski <moorray3@wp.pl> Cc: stable@vger.kernel.org Cc: linux-serial@vger.kernel.org Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
Julia Cartwright <julia@ni.com> Acked-by:
Jakub Kicinski <kubakici@wp.pl> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
04da7380