56 lines
2.3 KiB
Diff
56 lines
2.3 KiB
Diff
Subject: sc16is7xx: Drop bogus use of IRQF_ONESHOT
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From: Josh Cartwright <joshc@ni.com>
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Date: Thu, 18 Feb 2016 11:26:12 -0600
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.8/older/patches-4.8.14-rt9.tar.xz
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The use of IRQF_ONESHOT when registering an interrupt handler with
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request_irq() is non-sensical.
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Not only that, it also prevents the handler from being threaded when it
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otherwise should be w/ IRQ_FORCED_THREADING is enabled. This causes the
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following deadlock observed by Sean Nyekjaer on -rt:
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Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
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[..]
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rt_spin_lock_slowlock from (queue_kthread_work+0x18/0x74)
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queue_kthread_work) from (sc16is7xx_irq+0x10/0x18 [sc16is7xx])
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sc16is7xx_irq [sc16is7xx]) from (handle_irq_event_percpu+0x70/0x158)
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handle_irq_event_percpu) from (handle_irq_event+0x68/0xa8)
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handle_irq_event) from (handle_level_irq+0x10c/0x184)
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handle_level_irq) from (generic_handle_irq+0x2c/0x3c)
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generic_handle_irq) from (mxc_gpio_irq_handler+0x3c/0x108)
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mxc_gpio_irq_handler) from (mx3_gpio_irq_handler+0x80/0xcc)
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mx3_gpio_irq_handler) from (generic_handle_irq+0x2c/0x3c)
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generic_handle_irq) from (__handle_domain_irq+0x7c/0xe8)
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__handle_domain_irq) from (gic_handle_irq+0x24/0x5c)
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gic_handle_irq) from (__irq_svc+0x40/0x88)
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(__irq_svc) from (rt_spin_unlock+0x1c/0x68)
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(rt_spin_unlock) from (kthread_worker_fn+0x104/0x17c)
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(kthread_worker_fn) from (kthread+0xd0/0xe8)
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(kthread) from (ret_from_fork+0x14/0x2c)
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Fixes: 9e6f4ca3e567 ("sc16is7xx: use kthread_worker for tx_work and irq")
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Reported-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
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Signed-off-by: Josh Cartwright <joshc@ni.com>
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Cc: linux-rt-users@vger.kernel.org
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Cc: Jakub Kicinski <moorray3@wp.pl>
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Cc: stable@vger.kernel.org
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Cc: linux-serial@vger.kernel.org
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Link: http://lkml.kernel.org/r/1455816372-13989-1-git-send-email-joshc@ni.com
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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drivers/tty/serial/sc16is7xx.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/drivers/tty/serial/sc16is7xx.c
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+++ b/drivers/tty/serial/sc16is7xx.c
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@@ -1240,7 +1240,7 @@ static int sc16is7xx_probe(struct device
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/* Setup interrupt */
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ret = devm_request_irq(dev, irq, sc16is7xx_irq,
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- IRQF_ONESHOT | flags, dev_name(dev), s);
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+ flags, dev_name(dev), s);
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if (!ret)
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return 0;
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