From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed 02 Dec 2015 11:34:07 +0100
Subject: rtmutex: trylock is okay on -RT
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: da77ceac3d20f27310a07a7c346a4ee6b40d6c28
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension
non-RT kernel could deadlock on rt_mutex_trylock() in softirq context. On
-RT we don't run softirqs in IRQ context but in thread context so it is
not a issue here.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
kernel/locking/rtmutex.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1962,7 +1962,11 @@ EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
int __sched __rt_mutex_trylock(struct rt_mutex *lock)
{
+#ifdef CONFIG_PREEMPT_RT
+ if (WARN_ON_ONCE(in_irq() || in_nmi()))
+#else
if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+#endif
return 0;
return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);