[ANNOUNCE] v4.11.12-rt16v4.11.12-rt16-patches

Dear RT folks!

I'm pleased to announce the v4.11.12-rt16 patch set.

Changes since v4.11.12-rt15:

  - Paul Gortmaker reported, that the unstable-TSC fixup on x86 need one
    additional patch from upstream.

  - Apparmor is protecting per-CPU variables with preempt-disable
    resulting in "sleeping while atomic" warnings.

Known issues
	None

The delta patch against v4.11.12-rt15 is appended below and can be found here:

     https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/incr/patch-4.11.12-rt15-rt16.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 v4.11.12-rt16

The RT patch against v4.11.12 can be found here:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patch-4.11.12-rt16.patch.xz

The split quilt queue is available at:

    https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.12-rt16.tar.xz

Sebastian

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

10 files changed, 251 insertions, 18 deletions

diff --git a/patches/0001-sched-clock-Fix-early-boot-preempt-assumption-in-__s.patch b/patches/0001-sched-clock-Fix-early-boot-preempt-assumption-in-__s.patch
index 9072fe63ca6d..e9ba34641b35 100644
--- a/patches/0001-sched-clock-Fix-early-boot-preempt-assumption-in-__s.patch
+++ b/patches/0001-sched-clock-Fix-early-boot-preempt-assumption-in-__s.patch
@@ -38,7 +38,7 @@ Signed-off-by: Ingo Molnar <mingo@kernel.org>
 
 --- a/kernel/sched/clock.c
 +++ b/kernel/sched/clock.c
-@@ -126,12 +126,19 @@ int sched_clock_stable(void)
+@@ -132,12 +132,19 @@ static void __scd_stamp(struct sched_clo
  
  static void __set_sched_clock_stable(void)
  {
diff --git a/patches/apparmor-use-a-locallock-instead-preempt_disable.patch b/patches/apparmor-use-a-locallock-instead-preempt_disable.patch
new file mode 100644
index 000000000000..57a4cd2cc609
--- /dev/null
+++ b/patches/apparmor-use-a-locallock-instead-preempt_disable.patch
@@ -0,0 +1,83 @@
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 11 Oct 2017 17:43:49 +0200
+Subject: apparmor: use a locallock instead preempt_disable()
+
+get_buffers() disables preemption which acts as a lock for the per-CPU
+variable. Since we can't disable preemption here on RT, a local_lock is
+used in order to remain on the same CPU and not to have more than one user
+within the critical section.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ security/apparmor/include/path.h |   21 +++++++++++++++++----
+ security/apparmor/lsm.c          |    2 +-
+ 2 files changed, 18 insertions(+), 5 deletions(-)
+
+--- a/security/apparmor/include/path.h
++++ b/security/apparmor/include/path.h
+@@ -38,9 +38,10 @@ struct aa_buffers {
+ };
+ 
+ #include <linux/percpu.h>
+-#include <linux/preempt.h>
++#include <linux/locallock.h>
+ 
+ DECLARE_PER_CPU(struct aa_buffers, aa_buffers);
++DECLARE_LOCAL_IRQ_LOCK(aa_buffers_lock);
+ 
+ #define COUNT_ARGS(X...) COUNT_ARGS_HELPER(, ##X, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+ #define COUNT_ARGS_HELPER(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, X...) n
+@@ -54,12 +55,24 @@ DECLARE_PER_CPU(struct aa_buffers, aa_bu
+ 
+ #define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++)
+ 
+-#ifdef CONFIG_DEBUG_PREEMPT
++#ifdef CONFIG_PREEMPT_RT_BASE
++
++static inline void AA_BUG_PREEMPT_ENABLED(const char *s)
++{
++	struct local_irq_lock *lv;
++
++	lv = this_cpu_ptr(&aa_buffers_lock);
++	WARN_ONCE(lv->owner != current,
++		  "__get_buffer without aa_buffers_lock\n");
++}
++
++#elif CONFIG_DEBUG_PREEMPT
+ #define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X)
+ #else
+ #define AA_BUG_PREEMPT_ENABLED(X) /* nop */
+ #endif
+ 
++
+ #define __get_buffer(N) ({					\
+ 	struct aa_buffers *__cpu_var; \
+ 	AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled");  \
+@@ -72,14 +85,14 @@ DECLARE_PER_CPU(struct aa_buffers, aa_bu
+ 
+ #define get_buffers(X...)	\
+ do {				\
+-	preempt_disable();	\
++	local_lock(aa_buffers_lock);	\
+ 	__get_buffers(X);	\
+ } while (0)
+ 
+ #define put_buffers(X, Y...)	\
+ do {				\
+ 	__put_buffers(X, Y);	\
+-	preempt_enable();	\
++	local_unlock(aa_buffers_lock);	\
+ } while (0)
+ 
+ #endif /* __AA_PATH_H */
+--- a/security/apparmor/lsm.c
++++ b/security/apparmor/lsm.c
+@@ -42,7 +42,7 @@
+ int apparmor_initialized __initdata;
+ 
+ DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
+-
++DEFINE_LOCAL_IRQ_LOCK(aa_buffers_lock);
+ 
+ /*
+  * LSM hook functions
diff --git a/patches/cpu_chill-Add-a-UNINTERRUPTIBLE-hrtimer_nanosleep.patch b/patches/cpu_chill-Add-a-UNINTERRUPTIBLE-hrtimer_nanosleep.patch
index d3c5dfd0a55c..fa483e301775 100644
--- a/patches/cpu_chill-Add-a-UNINTERRUPTIBLE-hrtimer_nanosleep.patch
+++ b/patches/cpu_chill-Add-a-UNINTERRUPTIBLE-hrtimer_nanosleep.patch
@@ -33,7 +33,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 
 --- a/kernel/time/hrtimer.c
 +++ b/kernel/time/hrtimer.c
-@@ -1687,10 +1687,11 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper_o
+@@ -1689,10 +1689,11 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper_o
  #endif
  
  
@@ -47,7 +47,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  		hrtimer_start_expires(&t->timer, mode);
  
  		if (likely(t->task))
-@@ -1732,7 +1733,8 @@ long __sched hrtimer_nanosleep_restart(s
+@@ -1734,7 +1735,8 @@ long __sched hrtimer_nanosleep_restart(s
  				      HRTIMER_MODE_ABS, current);
  	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
  
@@ -57,7 +57,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  		goto out;
  
  	rmtp = restart->nanosleep.rmtp;
-@@ -1749,8 +1751,10 @@ long __sched hrtimer_nanosleep_restart(s
+@@ -1751,8 +1753,10 @@ long __sched hrtimer_nanosleep_restart(s
  	return ret;
  }
  
@@ -70,7 +70,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  {
  	struct restart_block *restart;
  	struct hrtimer_sleeper t;
-@@ -1764,7 +1768,7 @@ long hrtimer_nanosleep(struct timespec *
+@@ -1766,7 +1770,7 @@ long hrtimer_nanosleep(struct timespec *
  	hrtimer_init_sleeper_on_stack(&t, clockid, mode, current);
  	hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
  
@@ -79,7 +79,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  		goto out;
  
  	/* Absolute timers do not update the rmtp value and restart: */
-@@ -1791,6 +1795,12 @@ long hrtimer_nanosleep(struct timespec *
+@@ -1793,6 +1797,12 @@ long hrtimer_nanosleep(struct timespec *
  	return ret;
  }
  
@@ -92,7 +92,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
  		struct timespec __user *, rmtp)
  {
-@@ -1817,7 +1827,8 @@ void cpu_chill(void)
+@@ -1819,7 +1829,8 @@ void cpu_chill(void)
  	unsigned int freeze_flag = current->flags & PF_NOFREEZE;
  
  	current->flags |= PF_NOFREEZE;
diff --git a/patches/localversion.patch b/patches/localversion.patch
index 340816c8febc..0cccc7790a5d 100644
--- a/patches/localversion.patch
+++ b/patches/localversion.patch
@@ -10,4 +10,4 @@ Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 --- /dev/null
 +++ b/localversion-rt
 @@ -0,0 +1 @@
-+-rt15
++-rt16
diff --git a/patches/rt-introduce-cpu-chill.patch b/patches/rt-introduce-cpu-chill.patch
index 47e01a46017c..51b2ac0ed9cb 100644
--- a/patches/rt-introduce-cpu-chill.patch
+++ b/patches/rt-introduce-cpu-chill.patch
@@ -100,7 +100,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  #endif /* defined(_LINUX_DELAY_H) */
 --- a/kernel/time/hrtimer.c
 +++ b/kernel/time/hrtimer.c
-@@ -1805,6 +1805,25 @@ SYSCALL_DEFINE2(nanosleep, struct timesp
+@@ -1807,6 +1807,25 @@ SYSCALL_DEFINE2(nanosleep, struct timesp
  	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
  }
  
diff --git a/patches/sched-clock-Initialize-all-per-CPU-state-before-swit.patch b/patches/sched-clock-Initialize-all-per-CPU-state-before-swit.patch
index 1ac686c4f189..30a598e48ada 100644
--- a/patches/sched-clock-Initialize-all-per-CPU-state-before-swit.patch
+++ b/patches/sched-clock-Initialize-all-per-CPU-state-before-swit.patch
@@ -3,6 +3,8 @@ Date: Fri, 21 Apr 2017 12:11:53 +0200
 Subject: [PATCH] sched/clock: Initialize all per-CPU state before switching
  (back) to unstable
 
+commit cf15ca8deda86b27b66e27848b4b0fe58098fc0b upstream.
+
 In preparation for not keeping the sched_clock_tick() active for
 stable TSC, we need to explicitly initialize all per-CPU state
 before switching back to unstable.
diff --git a/patches/series b/patches/series
index d6f4af4c0253..17eb43e9eef9 100644
--- a/patches/series
+++ b/patches/series
@@ -6,6 +6,7 @@
 # UPSTREAM changes queued
 ############################################################
 sched-clock-Initialize-all-per-CPU-state-before-swit.patch
+x86-tsc-sched-clock-clocksource-Use-clocksource-watc.patch
 
 ############################################################
 # UPSTREAM FIXES, patches pending
@@ -142,7 +143,6 @@ hrtimer-Remove-hrtimer_peek_ahead_timers-leftovers.patch
 0017-hrtimer-Implementation-of-softirq-hrtimer-handling.patch
 0018-hrtimer-Enable-soft-and-hard-hrtimer.patch
 hrtimer-soft-bases-timekeeping.patch
-time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch
 0019-can-bcm-Replace-hrtimer_tasklet-with-softirq-based-h.patch
 0020-mac80211_hwsim-Replace-hrtimer-tasklet-with-softirq-.patch
 0021-xfrm-Replace-hrtimer-tasklet-with-softirq-hrtimer.patch
@@ -433,6 +433,7 @@ x86-kvm-require-const-tsc-for-rt.patch
 hrtimer-consolidate-hrtimer_init-hrtimer_init_sleepe.patch
 hrtimers-prepare-full-preemption.patch
 hrtimer-by-timers-by-default-into-the-softirq-context.patch
+time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch
 time-hrtimer-Use-softirq-based-wakeups-for-non-RT-th.patch
 timer-fd-avoid-live-lock.patch
 
@@ -749,6 +750,9 @@ move_sched_delayed_work_to_helper.patch
 # MD
 md-disable-bcache.patch
 
+# Security
+apparmor-use-a-locallock-instead-preempt_disable.patch
+
 # WORKQUEUE SIGH
 workqueue-prevent-deadlock-stall.patch
 
diff --git a/patches/time-hrtimer-Use-softirq-based-wakeups-for-non-RT-th.patch b/patches/time-hrtimer-Use-softirq-based-wakeups-for-non-RT-th.patch
index 4493e1b8ad5d..26a9dbd0e997 100644
--- a/patches/time-hrtimer-Use-softirq-based-wakeups-for-non-RT-th.patch
+++ b/patches/time-hrtimer-Use-softirq-based-wakeups-for-non-RT-th.patch
@@ -16,7 +16,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 
 --- a/kernel/time/hrtimer.c
 +++ b/kernel/time/hrtimer.c
-@@ -1604,14 +1604,31 @@ static enum hrtimer_restart hrtimer_wake
+@@ -1606,14 +1606,31 @@ static enum hrtimer_restart hrtimer_wake
  	return HRTIMER_NORESTART;
  }
  
diff --git a/patches/time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch b/patches/time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch
index c7da128a48de..829fb928a733 100644
--- a/patches/time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch
+++ b/patches/time-hrtimer-use-a-MONOTIC-clock-for-relative-REALTI.patch
@@ -10,14 +10,12 @@ for the SOFT-irq based clock but was forgotten for the HARD-irq clock.
 
 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 ---
- kernel/time/hrtimer.c | 2 ++
+ kernel/time/hrtimer.c |    2 ++
  1 file changed, 2 insertions(+)
 
-diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
-index cdd7cd35da11..b7c2ea23a320 100644
 --- a/kernel/time/hrtimer.c
 +++ b/kernel/time/hrtimer.c
-@@ -1258,6 +1258,8 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+@@ -1234,6 +1234,8 @@ static void __hrtimer_init(struct hrtime
  			clock_id = CLOCK_MONOTONIC;
  		else if (clock_id == CLOCK_REALTIME_SOFT)
  			clock_id = CLOCK_MONOTONIC_SOFT;
@@ -26,6 +24,3 @@ index cdd7cd35da11..b7c2ea23a320 100644
  	}
  
  	base = hrtimer_clockid_to_base(clock_id);
--- 
-2.14.2
-
diff --git a/patches/x86-tsc-sched-clock-clocksource-Use-clocksource-watc.patch b/patches/x86-tsc-sched-clock-clocksource-Use-clocksource-watc.patch
new file mode 100644
index 000000000000..b93dd4f855a5
--- /dev/null
+++ b/patches/x86-tsc-sched-clock-clocksource-Use-clocksource-watc.patch
@@ -0,0 +1,149 @@
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 21 Apr 2017 12:14:13 +0200
+Subject: [PATCH] x86/tsc, sched/clock, clocksource: Use clocksource watchdog
+ to provide stable sync points
+
+commit b421b22b00b0011f6a2ce3561176c4e79e640c49 upstream.
+
+Currently we keep sched_clock_tick() active for stable TSC in order to
+keep the per-CPU state semi up-to-date. The (obvious) problem is that
+by the time we detect TSC is borked, our per-CPU state is also borked.
+
+So hook into the clocksource watchdog and call a method after we've
+found it to still be stable.
+
+There's the obvious race where the TSC goes wonky between finding it
+stable and us running the callback, but closing that is too much work
+and not really worth it, since we're already detecting TSC wobbles
+after the fact, so we cannot, per definition, fully avoid funny clock
+values.
+
+And since the watchdog runs less often than the tick, this is also an
+optimization.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: Mike Galbraith <efault@gmx.de>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Cc: linux-kernel@vger.kernel.org
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+
+---
+ arch/x86/kernel/tsc.c       |   10 ++++++++++
+ include/linux/clocksource.h |    1 +
+ include/linux/sched/clock.h |    2 +-
+ kernel/sched/clock.c        |   36 +++++++++++++++++++++++++++---------
+ kernel/time/clocksource.c   |    3 +++
+ 5 files changed, 42 insertions(+), 10 deletions(-)
+
+--- a/arch/x86/kernel/tsc.c
++++ b/arch/x86/kernel/tsc.c
+@@ -1127,6 +1127,15 @@ static void tsc_cs_mark_unstable(struct
+ 	pr_info("Marking TSC unstable due to clocksource watchdog\n");
+ }
+ 
++static void tsc_cs_tick_stable(struct clocksource *cs)
++{
++	if (tsc_unstable)
++		return;
++
++	if (using_native_sched_clock())
++		sched_clock_tick_stable();
++}
++
+ /*
+  * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc()
+  */
+@@ -1140,6 +1149,7 @@ static struct clocksource clocksource_ts
+ 	.archdata               = { .vclock_mode = VCLOCK_TSC },
+ 	.resume			= tsc_resume,
+ 	.mark_unstable		= tsc_cs_mark_unstable,
++	.tick_stable		= tsc_cs_tick_stable,
+ };
+ 
+ void mark_tsc_unstable(char *reason)
+--- a/include/linux/clocksource.h
++++ b/include/linux/clocksource.h
+@@ -96,6 +96,7 @@ struct clocksource {
+ 	void (*suspend)(struct clocksource *cs);
+ 	void (*resume)(struct clocksource *cs);
+ 	void (*mark_unstable)(struct clocksource *cs);
++	void (*tick_stable)(struct clocksource *cs);
+ 
+ 	/* private: */
+ #ifdef CONFIG_CLOCKSOURCE_WATCHDOG
+--- a/include/linux/sched/clock.h
++++ b/include/linux/sched/clock.h
+@@ -63,8 +63,8 @@ extern void clear_sched_clock_stable(voi
+  */
+ extern u64 __sched_clock_offset;
+ 
+-
+ extern void sched_clock_tick(void);
++extern void sched_clock_tick_stable(void);
+ extern void sched_clock_idle_sleep_event(void);
+ extern void sched_clock_idle_wakeup_event(u64 delta_ns);
+ 
+--- a/kernel/sched/clock.c
++++ b/kernel/sched/clock.c
+@@ -366,20 +366,38 @@ void sched_clock_tick(void)
+ {
+ 	struct sched_clock_data *scd;
+ 
++	if (sched_clock_stable())
++		return;
++
++	if (unlikely(!sched_clock_running))
++		return;
++
+ 	WARN_ON_ONCE(!irqs_disabled());
+ 
+-	/*
+-	 * Update these values even if sched_clock_stable(), because it can
+-	 * become unstable at any point in time at which point we need some
+-	 * values to fall back on.
+-	 *
+-	 * XXX arguably we can skip this if we expose tsc_clocksource_reliable
+-	 */
+ 	scd = this_scd();
+ 	__scd_stamp(scd);
++	sched_clock_local(scd);
++}
+ 
+-	if (!sched_clock_stable() && likely(sched_clock_running))
+-		sched_clock_local(scd);
++void sched_clock_tick_stable(void)
++{
++	u64 gtod, clock;
++
++	if (!sched_clock_stable())
++		return;
++
++	/*
++	 * Called under watchdog_lock.
++	 *
++	 * The watchdog just found this TSC to (still) be stable, so now is a
++	 * good moment to update our __gtod_offset. Because once we find the
++	 * TSC to be unstable, any computation will be computing crap.
++	 */
++	local_irq_disable();
++	gtod = ktime_get_ns();
++	clock = sched_clock();
++	__gtod_offset = (clock + __sched_clock_offset) - gtod;
++	local_irq_enable();
+ }
+ 
+ /*
+--- a/kernel/time/clocksource.c
++++ b/kernel/time/clocksource.c
+@@ -233,6 +233,9 @@ static void clocksource_watchdog(unsigne
+ 			continue;
+ 		}
+ 
++		if (cs == curr_clocksource && cs->tick_stable)
++			cs->tick_stable(cs);
++
+ 		if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
+ 		    (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
+ 		    (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {