blob: 942a804c6c107981c7a6a7d5c51154ac853210da [file] [log] [blame]
From 862a6c0ccc672374fb0ab35fdacef9b9238667c5 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 15 Nov 2015 18:40:17 +0100
Subject: [PATCH] irqwork: Move irq safe work to irq context
On architectures where arch_irq_work_has_interrupt() returns false, we
end up running the irq safe work from the softirq context. That
results in a potential deadlock in the scheduler irq work which
expects that function to be called with interrupts disabled.
Split the irq_work_tick() function into a hard and soft variant. Call
the hard variant from the tick interrupt and add the soft variant to
the timer softirq.
Reported-and-tested-by: Yanjiang Jin <yanjiang.jin@windriver.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 0e427a9997f3..2543aab05daa 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -52,4 +52,10 @@ static inline bool irq_work_needs_cpu(void) { return false; }
static inline void irq_work_run(void) { }
#endif
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+void irq_work_tick_soft(void);
+#else
+static inline void irq_work_tick_soft(void) { }
+#endif
+
#endif /* _LINUX_IRQ_WORK_H */
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 0ddaf1e66d8c..2899ba0d23d1 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -200,8 +200,17 @@ void irq_work_tick(void)
if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
irq_work_run_list(raised);
+
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT_FULL))
+ irq_work_run_list(this_cpu_ptr(&lazy_list));
+}
+
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+void irq_work_tick_soft(void)
+{
irq_work_run_list(this_cpu_ptr(&lazy_list));
}
+#endif
/*
* Synchronize against the irq_work @entry, ensures the entry is not
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index dc70267717f6..5c78f7f2beed 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1623,7 +1623,7 @@ void update_process_times(int user_tick)
scheduler_tick();
run_local_timers();
rcu_check_callbacks(user_tick);
-#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
+#if defined(CONFIG_IRQ_WORK)
if (in_irq())
irq_work_tick();
#endif
@@ -1677,9 +1677,7 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)
*/
base->must_forward_clk = false;
-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
- irq_work_tick();
-#endif
+ irq_work_tick_soft();
__run_timers(base);
if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active)
--
2.1.4