Messages in this thread Patch in this message |  | | From | Julia Cartwright <> | Subject | [PATCH] sc16is7xx: Drop bogus use of IRQF_ONESHOT | Date | Mon, 3 Oct 2016 10:14:32 -0500 |
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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: 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> --- This patch has been in -rt for a little while, but it isn't -rt specific.
See relevant bug report thread which starts here:
http://www.spinics.net/lists/linux-rt-users/msg14620.html
drivers/tty/serial/sc16is7xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index a9d94f7..96a374d 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1260,7 +1260,7 @@ static int sc16is7xx_probe(struct device *dev, /* 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; -- 2.9.3
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