[ANNOUNCE] 4.1.13-rt15

Dear RT folks!

I'm pleased to announce the v4.1.13-rt15 patch set.
Changes since v4.1.13-rt14:

Sebastian Andrzej Siewior (1):
      v4.1.13-rt15

Thomas Gleixner (1):
      irqwork: Move irq safe work to irq context

Known issues:
  - bcache stays disabled

  - CPU hotplug is not better than before

  - The netlink_release() OOPS, reported by Clark, is still on the
    list, but unsolved due to lack of information

The delta patch against 4.1.13-rt15 is appended below and can be found here:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.1/incr/patch-4.1.13-rt14-rt15.patch.xz

You can get this release via the git tree at:

    git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.1.13-rt15

The RT patch against 4.1.13 can be found here:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.1/patch-4.1.13-rt15.patch.xz

The split quilt queue is available at:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.1/patches-4.1.13-rt15.tar.xz

Sebastian

diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
--- 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
--- 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
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1455,7 +1455,7 @@ 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
@@ -1471,9 +1471,7 @@ static void run_timer_softirq(struct softirq_action *h)

 	hrtimer_run_pending();

-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
-	irq_work_tick();
-#endif
+	irq_work_tick_soft();

 	if (time_after_eq(jiffies, base->timer_jiffies))
 		__run_timers(base);
diff --git a/localversion-rt b/localversion-rt
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt14
+-rt15

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

3 files changed, 86 insertions, 2 deletions

diff --git a/patches/irqwork-Move-irq-safe-work-to-irq-context.patch b/patches/irqwork-Move-irq-safe-work-to-irq-context.patch
new file mode 100644
index 00000000000000..99c5a41041c6a9
--- /dev/null
+++ b/patches/irqwork-Move-irq-safe-work-to-irq-context.patch
@@ -0,0 +1,83 @@
+Subject: irqwork: Move irq safe work to irq context
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 15 Nov 2015 18:40:17 +0100
+
+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
+---
+ include/linux/irq_work.h |    6 ++++++
+ kernel/irq_work.c        |    9 +++++++++
+ kernel/time/timer.c      |    6 ++----
+ 3 files changed, 17 insertions(+), 4 deletions(-)
+
+Index: linux-rt-devel/include/linux/irq_work.h
+===================================================================
+--- linux-rt-devel.orig/include/linux/irq_work.h
++++ linux-rt-devel/include/linux/irq_work.h
+@@ -52,4 +52,10 @@ static inline bool irq_work_needs_cpu(vo
+ 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 */
+Index: linux-rt-devel/kernel/irq_work.c
+===================================================================
+--- linux-rt-devel.orig/kernel/irq_work.c
++++ linux-rt-devel/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
+Index: linux-rt-devel/kernel/time/timer.c
+===================================================================
+--- linux-rt-devel.orig/kernel/time/timer.c
++++ linux-rt-devel/kernel/time/timer.c
+@@ -1455,7 +1455,7 @@ 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
+@@ -1471,9 +1471,7 @@ static void run_timer_softirq(struct sof
+ 
+ 	hrtimer_run_pending();
+ 
+-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+-	irq_work_tick();
+-#endif
++	irq_work_tick_soft();
+ 
+ 	if (time_after_eq(jiffies, base->timer_jiffies))
+ 		__run_timers(base);
diff --git a/patches/localversion.patch b/patches/localversion.patch
index 9979b294ecb5d4..73791b7238aabc 100644
--- a/patches/localversion.patch
+++ b/patches/localversion.patch
@@ -1,4 +1,4 @@
-Subject: v4.1.13-rt14
+Subject: v4.1.13-rt15
 From: Thomas Gleixner <tglx@linutronix.de>
 Date: Fri, 08 Jul 2011 20:25:16 +0200
 
@@ -10,4 +10,4 @@ Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 --- /dev/null
 +++ b/localversion-rt
 @@ -0,0 +1 @@
-+-rt14
++-rt15
diff --git a/patches/series b/patches/series
index 3fb0a5aa1f54d7..c9cf63a135c1a4 100644
--- a/patches/series
+++ b/patches/series
@@ -434,6 +434,7 @@ net-core-cpuhotplug-drain-input_pkt_queue-lockless.patch
 
 # irqwork
 irqwork-push_most_work_into_softirq_context.patch
+irqwork-Move-irq-safe-work-to-irq-context.patch
 
 # Sound
 snd-pcm-fix-snd_pcm_stream_lock-irqs_disabled-splats.patch