From 2ed0e645f358c26f4f4a7aed56a9488db0020ad1 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 16 Nov 2011 12:27:39 +0000 Subject: genirq: Don't allow per cpu interrupts to be suspended The power management functions related to interrupts do not know (yet) about per-cpu interrupts and end up calling the wrong low-level methods to enable/disable interrupts. This leads to all kind of interesting issues (action taken on one CPU only, updating a refcount which is not used otherwise...). The workaround for the time being is simply to flag these interrupts with IRQF_NO_SUSPEND. At least on ARM, these interrupts are actually dealt with at the architecture level. Reported-by: Santosh Shilimkar Tested-by: Santosh Shilimkar Signed-off-by: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1321446459-31409-1-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 67ce837ae52c..0e2b179bc7b3 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1596,7 +1596,7 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler, return -ENOMEM; action->handler = handler; - action->flags = IRQF_PERCPU; + action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND; action->name = devname; action->percpu_dev_id = dev_id; -- cgit v1.2.2 From 550acb19269d65f32e9ac4ddb26c2b2070e37f1c Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Thu, 1 Dec 2011 13:55:08 +0200 Subject: genirq: Fix race condition when stopping the irq thread In irq_wait_for_interrupt(), the should_stop member is verified before setting the task's state to TASK_INTERRUPTIBLE and calling schedule(). In case kthread_stop sets should_stop and wakes up the process after should_stop is checked by the irq thread but before the task's state is changed, the irq thread might never exit: kthread_stop irq_wait_for_interrupt ------------ ---------------------- ... ... while (!kthread_should_stop()) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); ... set_current_state(TASK_INTERRUPTIBLE); ... schedule(); } Fix this by checking if the thread should stop after modifying the task's state. [ tglx: Simplified it a bit ] Signed-off-by: Ido Yariv Link: http://lkml.kernel.org/r/1322740508-22640-1-git-send-email-ido@wizery.com Signed-off-by: Thomas Gleixner Cc: stable@kernel.org --- kernel/irq/manage.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0e2b179bc7b3..1da999f5e746 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -623,8 +623,9 @@ static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id) static int irq_wait_for_interrupt(struct irqaction *action) { + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { - set_current_state(TASK_INTERRUPTIBLE); if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) { @@ -632,7 +633,9 @@ static int irq_wait_for_interrupt(struct irqaction *action) return 0; } schedule(); + set_current_state(TASK_INTERRUPTIBLE); } + __set_current_state(TASK_RUNNING); return -1; } -- cgit v1.2.2