| From 04da73803c05dc1150ccc31cbf93e8cd56679c09 Mon Sep 17 00:00:00 2001 |
| From: Josh Cartwright <joshc@ni.com> |
| Date: Thu, 13 Oct 2016 10:44:33 -0500 |
| Subject: sc16is7xx: Drop bogus use of IRQF_ONESHOT |
| |
| From: Josh Cartwright <joshc@ni.com> |
| |
| commit 04da73803c05dc1150ccc31cbf93e8cd56679c09 upstream. |
| |
| 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: 9e6f4ca3e567 ("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: 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/tty/serial/sc16is7xx.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/tty/serial/sc16is7xx.c |
| +++ b/drivers/tty/serial/sc16is7xx.c |
| @@ -1240,7 +1240,7 @@ static int sc16is7xx_probe(struct device |
| |
| /* Setup interrupt */ |
| ret = devm_request_irq(dev, irq, sc16is7xx_irq, |
| - IRQF_ONESHOT | flags, dev_name(dev), s); |
| + flags, dev_name(dev), s); |
| if (!ret) |
| return 0; |
| |