This is a note to let you know that I've just added the patch titled sc16is7xx: Drop bogus use of IRQF_ONESHOT to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sc16is7xx-drop-bogus-use-of-irqf_oneshot.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 04da73803c05dc1150ccc31cbf93e8cd56679c09 Mon Sep 17 00:00:00 2001 From: Josh Cartwright <joshc@xxxxxx> Date: Thu, 13 Oct 2016 10:44:33 -0500 Subject: sc16is7xx: Drop bogus use of IRQF_ONESHOT From: Josh Cartwright <joshc@xxxxxx> 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@xxxxxxxxx> Signed-off-by: Josh Cartwright <joshc@xxxxxx> Cc: linux-rt-users@xxxxxxxxxxxxxxx Cc: Jakub Kicinski <moorray3@xxxxx> Cc: linux-serial@xxxxxxxxxxxxxxx Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Signed-off-by: Julia Cartwright <julia@xxxxxx> Acked-by: Jakub Kicinski <kubakici@xxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -1264,7 +1264,7 @@ 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; Patches currently in stable-queue which might be from joshc@xxxxxx are queue-4.9/sc16is7xx-drop-bogus-use-of-irqf_oneshot.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html