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Subject[ANNOUNCE] v4.11.12-rt16
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
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1127,6 +1127,15 @@ static void tsc_cs_mark_unstable(struct clocksource *cs)
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_tsc = {
.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)
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
--- 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
diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h
--- a/include/linux/sched/clock.h
+++ b/include/linux/sched/clock.h
@@ -63,8 +63,8 @@ extern void clear_sched_clock_stable(void);
*/
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);

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -373,20 +373,38 @@ 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();
}

/*
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -233,6 +233,9 @@ static void clocksource_watchdog(unsigned long data)
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)) {
diff --git a/localversion-rt b/localversion-rt
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt15
+-rt16
diff --git a/security/apparmor/include/path.h b/security/apparmor/include/path.h
--- 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_buffers);

#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_buffers);

#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 */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
--- 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
\
 
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