Merge tag 'v4.14-rc3' into irq/irqchip-4.15

Required merge to get mainline irqchip updates.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

16 files changed, 542 insertions, 237 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index acf5308fad51..8de11a29e495 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -46,11 +46,13 @@
  * @bringup:	Single callback bringup or teardown selector
  * @cb_state:	The state for a single callback (install/uninstall)
  * @result:	Result of the operation
- * @done:	Signal completion to the issuer of the task
+ * @done_up:	Signal completion to the issuer of the task for cpu-up
+ * @done_down:	Signal completion to the issuer of the task for cpu-down
  */
 struct cpuhp_cpu_state {
 	enum cpuhp_state	state;
 	enum cpuhp_state	target;
+	enum cpuhp_state	fail;
 #ifdef CONFIG_SMP
 	struct task_struct	*thread;
 	bool			should_run;
@@ -58,18 +60,39 @@ struct cpuhp_cpu_state {
 	bool			single;
 	bool			bringup;
 	struct hlist_node	*node;
+	struct hlist_node	*last;
 	enum cpuhp_state	cb_state;
 	int			result;
-	struct completion	done;
+	struct completion	done_up;
+	struct completion	done_down;
 #endif
 };
 
-static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
+static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
+	.fail = CPUHP_INVALID,
+};
 
 #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
-static struct lock_class_key cpuhp_state_key;
-static struct lockdep_map cpuhp_state_lock_map =
-	STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key);
+static struct lockdep_map cpuhp_state_up_map =
+	STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
+static struct lockdep_map cpuhp_state_down_map =
+	STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
+
+
+static void inline cpuhp_lock_acquire(bool bringup)
+{
+	lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+
+static void inline cpuhp_lock_release(bool bringup)
+{
+	lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+#else
+
+static void inline cpuhp_lock_acquire(bool bringup) { }
+static void inline cpuhp_lock_release(bool bringup) { }
+
 #endif
 
 /**
@@ -123,13 +146,16 @@ static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
 /**
  * cpuhp_invoke_callback _ Invoke the callbacks for a given state
  * @cpu:	The cpu for which the callback should be invoked
- * @step:	The step in the state machine
+ * @state:	The state to do callbacks for
  * @bringup:	True if the bringup callback should be invoked
+ * @node:	For multi-instance, do a single entry callback for install/remove
+ * @lastp:	For multi-instance rollback, remember how far we got
  *
  * Called from cpu hotplug and from the state register machinery.
  */
 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
-				 bool bringup, struct hlist_node *node)
+				 bool bringup, struct hlist_node *node,
+				 struct hlist_node **lastp)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
 	struct cpuhp_step *step = cpuhp_get_step(state);
@@ -137,7 +163,17 @@ static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
 	int (*cb)(unsigned int cpu);
 	int ret, cnt;
 
+	if (st->fail == state) {
+		st->fail = CPUHP_INVALID;
+
+		if (!(bringup ? step->startup.single : step->teardown.single))
+			return 0;
+
+		return -EAGAIN;
+	}
+
 	if (!step->multi_instance) {
+		WARN_ON_ONCE(lastp && *lastp);
 		cb = bringup ? step->startup.single : step->teardown.single;
 		if (!cb)
 			return 0;
@@ -152,6 +188,7 @@ static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
 
 	/* Single invocation for instance add/remove */
 	if (node) {
+		WARN_ON_ONCE(lastp && *lastp);
 		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
 		ret = cbm(cpu, node);
 		trace_cpuhp_exit(cpu, st->state, state, ret);
@@ -161,13 +198,23 @@ static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
 	/* State transition. Invoke on all instances */
 	cnt = 0;
 	hlist_for_each(node, &step->list) {
+		if (lastp && node == *lastp)
+			break;
+
 		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
 		ret = cbm(cpu, node);
 		trace_cpuhp_exit(cpu, st->state, state, ret);
-		if (ret)
-			goto err;
+		if (ret) {
+			if (!lastp)
+				goto err;
+
+			*lastp = node;
+			return ret;
+		}
 		cnt++;
 	}
+	if (lastp)
+		*lastp = NULL;
 	return 0;
 err:
 	/* Rollback the instances if one failed */
@@ -178,12 +225,39 @@ err:
 	hlist_for_each(node, &step->list) {
 		if (!cnt--)
 			break;
-		cbm(cpu, node);
+
+		trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
+		ret = cbm(cpu, node);
+		trace_cpuhp_exit(cpu, st->state, state, ret);
+		/*
+		 * Rollback must not fail,
+		 */
+		WARN_ON_ONCE(ret);
 	}
 	return ret;
 }
 
 #ifdef CONFIG_SMP
+static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
+{
+	struct completion *done = bringup ? &st->done_up : &st->done_down;
+	wait_for_completion(done);
+}
+
+static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
+{
+	struct completion *done = bringup ? &st->done_up : &st->done_down;
+	complete(done);
+}
+
+/*
+ * The former STARTING/DYING states, ran with IRQs disabled and must not fail.
+ */
+static bool cpuhp_is_atomic_state(enum cpuhp_state state)
+{
+	return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;
+}
+
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
 static DEFINE_MUTEX(cpu_add_remove_lock);
 bool cpuhp_tasks_frozen;
@@ -271,14 +345,79 @@ void cpu_hotplug_enable(void)
 EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
 #endif	/* CONFIG_HOTPLUG_CPU */
 
-static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st);
+static inline enum cpuhp_state
+cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state = st->state;
+
+	st->rollback = false;
+	st->last = NULL;
+
+	st->target = target;
+	st->single = false;
+	st->bringup = st->state < target;
+
+	return prev_state;
+}
+
+static inline void
+cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state)
+{
+	st->rollback = true;
+
+	/*
+	 * If we have st->last we need to undo partial multi_instance of this
+	 * state first. Otherwise start undo at the previous state.
+	 */
+	if (!st->last) {
+		if (st->bringup)
+			st->state--;
+		else
+			st->state++;
+	}
+
+	st->target = prev_state;
+	st->bringup = !st->bringup;
+}
+
+/* Regular hotplug invocation of the AP hotplug thread */
+static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st)
+{
+	if (!st->single && st->state == st->target)
+		return;
+
+	st->result = 0;
+	/*
+	 * Make sure the above stores are visible before should_run becomes
+	 * true. Paired with the mb() above in cpuhp_thread_fun()
+	 */
+	smp_mb();
+	st->should_run = true;
+	wake_up_process(st->thread);
+	wait_for_ap_thread(st, st->bringup);
+}
+
+static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state;
+	int ret;
+
+	prev_state = cpuhp_set_state(st, target);
+	__cpuhp_kick_ap(st);
+	if ((ret = st->result)) {
+		cpuhp_reset_state(st, prev_state);
+		__cpuhp_kick_ap(st);
+	}
+
+	return ret;
+}
 
 static int bringup_wait_for_ap(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
 
 	/* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
-	wait_for_completion(&st->done);
+	wait_for_ap_thread(st, true);
 	if (WARN_ON_ONCE((!cpu_online(cpu))))
 		return -ECANCELED;
 
@@ -286,12 +425,10 @@ static int bringup_wait_for_ap(unsigned int cpu)
 	stop_machine_unpark(cpu);
 	kthread_unpark(st->thread);
 
-	/* Should we go further up ? */
-	if (st->target > CPUHP_AP_ONLINE_IDLE) {
-		__cpuhp_kick_ap_work(st);
-		wait_for_completion(&st->done);
-	}
-	return st->result;
+	if (st->target <= CPUHP_AP_ONLINE_IDLE)
+		return 0;
+
+	return cpuhp_kick_ap(st, st->target);
 }
 
 static int bringup_cpu(unsigned int cpu)
@@ -317,32 +454,6 @@ static int bringup_cpu(unsigned int cpu)
 /*
  * Hotplug state machine related functions
  */
-static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
-{
-	for (st->state++; st->state < st->target; st->state++) {
-		struct cpuhp_step *step = cpuhp_get_step(st->state);
-
-		if (!step->skip_onerr)
-			cpuhp_invoke_callback(cpu, st->state, true, NULL);
-	}
-}
-
-static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
-				enum cpuhp_state target)
-{
-	enum cpuhp_state prev_state = st->state;
-	int ret = 0;
-
-	for (; st->state > target; st->state--) {
-		ret = cpuhp_invoke_callback(cpu, st->state, false, NULL);
-		if (ret) {
-			st->target = prev_state;
-			undo_cpu_down(cpu, st);
-			break;
-		}
-	}
-	return ret;
-}
 
 static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
 {
@@ -350,7 +461,7 @@ static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
 		struct cpuhp_step *step = cpuhp_get_step(st->state);
 
 		if (!step->skip_onerr)
-			cpuhp_invoke_callback(cpu, st->state, false, NULL);
+			cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
 	}
 }
 
@@ -362,7 +473,7 @@ static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
 
 	while (st->state < target) {
 		st->state++;
-		ret = cpuhp_invoke_callback(cpu, st->state, true, NULL);
+		ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
 		if (ret) {
 			st->target = prev_state;
 			undo_cpu_up(cpu, st);
@@ -379,7 +490,8 @@ static void cpuhp_create(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
 
-	init_completion(&st->done);
+	init_completion(&st->done_up);
+	init_completion(&st->done_down);
 }
 
 static int cpuhp_should_run(unsigned int cpu)
@@ -389,69 +501,90 @@ static int cpuhp_should_run(unsigned int cpu)
 	return st->should_run;
 }
 
-/* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */
-static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st)
-{
-	enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU);
-
-	return cpuhp_down_callbacks(cpu, st, target);
-}
-
-/* Execute the online startup callbacks. Used to be CPU_ONLINE */
-static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st)
-{
-	return cpuhp_up_callbacks(cpu, st, st->target);
-}
-
 /*
  * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
  * callbacks when a state gets [un]installed at runtime.
+ *
+ * Each invocation of this function by the smpboot thread does a single AP
+ * state callback.
+ *
+ * It has 3 modes of operation:
+ *  - single: runs st->cb_state
+ *  - up:     runs ++st->state, while st->state < st->target
+ *  - down:   runs st->state--, while st->state > st->target
+ *
+ * When complete or on error, should_run is cleared and the completion is fired.
  */
 static void cpuhp_thread_fun(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
-	int ret = 0;
+	bool bringup = st->bringup;
+	enum cpuhp_state state;
 
 	/*
-	 * Paired with the mb() in cpuhp_kick_ap_work and
-	 * cpuhp_invoke_ap_callback, so the work set is consistent visible.
+	 * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
+	 * that if we see ->should_run we also see the rest of the state.
 	 */
 	smp_mb();
-	if (!st->should_run)
+
+	if (WARN_ON_ONCE(!st->should_run))
 		return;
 
-	st->should_run = false;
+	cpuhp_lock_acquire(bringup);
 
-	lock_map_acquire(&cpuhp_state_lock_map);
-	/* Single callback invocation for [un]install ? */
 	if (st->single) {
-		if (st->cb_state < CPUHP_AP_ONLINE) {
-			local_irq_disable();
-			ret = cpuhp_invoke_callback(cpu, st->cb_state,
-						    st->bringup, st->node);
-			local_irq_enable();
+		state = st->cb_state;
+		st->should_run = false;
+	} else {
+		if (bringup) {
+			st->state++;
+			state = st->state;
+			st->should_run = (st->state < st->target);
+			WARN_ON_ONCE(st->state > st->target);
 		} else {
-			ret = cpuhp_invoke_callback(cpu, st->cb_state,
-						    st->bringup, st->node);
+			state = st->state;
+			st->state--;
+			st->should_run = (st->state > st->target);
+			WARN_ON_ONCE(st->state < st->target);
 		}
-	} else if (st->rollback) {
-		BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
+	}
+
+	WARN_ON_ONCE(!cpuhp_is_ap_state(state));
 
-		undo_cpu_down(cpu, st);
-		st->rollback = false;
+	if (st->rollback) {
+		struct cpuhp_step *step = cpuhp_get_step(state);
+		if (step->skip_onerr)
+			goto next;
+	}
+
+	if (cpuhp_is_atomic_state(state)) {
+		local_irq_disable();
+		st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
+		local_irq_enable();
+
+		/*
+		 * STARTING/DYING must not fail!
+		 */
+		WARN_ON_ONCE(st->result);
 	} else {
-		/* Cannot happen .... */
-		BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
-
-		/* Regular hotplug work */
-		if (st->state < st->target)
-			ret = cpuhp_ap_online(cpu, st);
-		else if (st->state > st->target)
-			ret = cpuhp_ap_offline(cpu, st);
+		st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
+	}
+
+	if (st->result) {
+		/*
+		 * If we fail on a rollback, we're up a creek without no
+		 * paddle, no way forward, no way back. We loose, thanks for
+		 * playing.
+		 */
+		WARN_ON_ONCE(st->rollback);
+		st->should_run = false;
 	}
-	lock_map_release(&cpuhp_state_lock_map);
-	st->result = ret;
-	complete(&st->done);
+
+next:
+	cpuhp_lock_release(bringup);
+
+	if (!st->should_run)
+		complete_ap_thread(st, bringup);
 }
 
 /* Invoke a single callback on a remote cpu */
@@ -460,62 +593,64 @@ cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
 			 struct hlist_node *node)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+	int ret;
 
 	if (!cpu_online(cpu))
 		return 0;
 
-	lock_map_acquire(&cpuhp_state_lock_map);
-	lock_map_release(&cpuhp_state_lock_map);
+	cpuhp_lock_acquire(false);
+	cpuhp_lock_release(false);
+
+	cpuhp_lock_acquire(true);
+	cpuhp_lock_release(true);
 
 	/*
 	 * If we are up and running, use the hotplug thread. For early calls
 	 * we invoke the thread function directly.
 	 */
 	if (!st->thread)
-		return cpuhp_invoke_callback(cpu, state, bringup, node);
+		return cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
 
+	st->rollback = false;
+	st->last = NULL;
+
+	st->node = node;
+	st->bringup = bringup;
 	st->cb_state = state;
 	st->single = true;
-	st->bringup = bringup;
-	st->node = node;
 
-	/*
-	 * Make sure the above stores are visible before should_run becomes
-	 * true. Paired with the mb() above in cpuhp_thread_fun()
-	 */
-	smp_mb();
-	st->should_run = true;
-	wake_up_process(st->thread);
-	wait_for_completion(&st->done);
-	return st->result;
-}
+	__cpuhp_kick_ap(st);
 
-/* Regular hotplug invocation of the AP hotplug thread */
-static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st)
-{
-	st->result = 0;
-	st->single = false;
 	/*
-	 * Make sure the above stores are visible before should_run becomes
-	 * true. Paired with the mb() above in cpuhp_thread_fun()
+	 * If we failed and did a partial, do a rollback.
 	 */
-	smp_mb();
-	st->should_run = true;
-	wake_up_process(st->thread);
+	if ((ret = st->result) && st->last) {
+		st->rollback = true;
+		st->bringup = !bringup;
+
+		__cpuhp_kick_ap(st);
+	}
+
+	return ret;
 }
 
 static int cpuhp_kick_ap_work(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
-	enum cpuhp_state state = st->state;
+	enum cpuhp_state prev_state = st->state;
+	int ret;
+
+	cpuhp_lock_acquire(false);
+	cpuhp_lock_release(false);
+
+	cpuhp_lock_acquire(true);
+	cpuhp_lock_release(true);
+
+	trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
+	ret = cpuhp_kick_ap(st, st->target);
+	trace_cpuhp_exit(cpu, st->state, prev_state, ret);
 
-	trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work);
-	lock_map_acquire(&cpuhp_state_lock_map);
-	lock_map_release(&cpuhp_state_lock_map);
-	__cpuhp_kick_ap_work(st);
-	wait_for_completion(&st->done);
-	trace_cpuhp_exit(cpu, st->state, state, st->result);
-	return st->result;
+	return ret;
 }
 
 static struct smp_hotplug_thread cpuhp_threads = {
@@ -581,6 +716,7 @@ static int take_cpu_down(void *_param)
 	struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
 	enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
 	int err, cpu = smp_processor_id();
+	int ret;
 
 	/* Ensure this CPU doesn't handle any more interrupts. */
 	err = __cpu_disable();
@@ -594,8 +730,13 @@ static int take_cpu_down(void *_param)
 	WARN_ON(st->state != CPUHP_TEARDOWN_CPU);
 	st->state--;
 	/* Invoke the former CPU_DYING callbacks */
-	for (; st->state > target; st->state--)
-		cpuhp_invoke_callback(cpu, st->state, false, NULL);
+	for (; st->state > target; st->state--) {
+		ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
+		/*
+		 * DYING must not fail!
+		 */
+		WARN_ON_ONCE(ret);
+	}
 
 	/* Give up timekeeping duties */
 	tick_handover_do_timer();
@@ -639,7 +780,7 @@ static int takedown_cpu(unsigned int cpu)
 	 *
 	 * Wait for the stop thread to go away.
 	 */
-	wait_for_completion(&st->done);
+	wait_for_ap_thread(st, false);
 	BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
 
 	/* Interrupts are moved away from the dying cpu, reenable alloc/free */
@@ -658,7 +799,7 @@ static void cpuhp_complete_idle_dead(void *arg)
 {
 	struct cpuhp_cpu_state *st = arg;
 
-	complete(&st->done);
+	complete_ap_thread(st, false);
 }
 
 void cpuhp_report_idle_dead(void)
@@ -676,11 +817,32 @@ void cpuhp_report_idle_dead(void)
 				 cpuhp_complete_idle_dead, st, 0);
 }
 
-#else
-#define takedown_cpu		NULL
-#endif
+static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
+{
+	for (st->state++; st->state < st->target; st->state++) {
+		struct cpuhp_step *step = cpuhp_get_step(st->state);
 
-#ifdef CONFIG_HOTPLUG_CPU
+		if (!step->skip_onerr)
+			cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
+	}
+}
+
+static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
+				enum cpuhp_state target)
+{
+	enum cpuhp_state prev_state = st->state;
+	int ret = 0;
+
+	for (; st->state > target; st->state--) {
+		ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
+		if (ret) {
+			st->target = prev_state;
+			undo_cpu_down(cpu, st);
+			break;
+		}
+	}
+	return ret;
+}
 
 /* Requires cpu_add_remove_lock to be held */
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
@@ -699,13 +861,13 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
 
 	cpuhp_tasks_frozen = tasks_frozen;
 
-	prev_state = st->state;
-	st->target = target;
+	prev_state = cpuhp_set_state(st, target);
 	/*
 	 * If the current CPU state is in the range of the AP hotplug thread,
 	 * then we need to kick the thread.
 	 */
 	if (st->state > CPUHP_TEARDOWN_CPU) {
+		st->target = max((int)target, CPUHP_TEARDOWN_CPU);
 		ret = cpuhp_kick_ap_work(cpu);
 		/*
 		 * The AP side has done the error rollback already. Just
@@ -720,6 +882,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
 		 */
 		if (st->state > CPUHP_TEARDOWN_CPU)
 			goto out;
+
+		st->target = target;
 	}
 	/*
 	 * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
@@ -727,9 +891,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
 	 */
 	ret = cpuhp_down_callbacks(cpu, st, target);
 	if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
-		st->target = prev_state;
-		st->rollback = true;
-		cpuhp_kick_ap_work(cpu);
+		cpuhp_reset_state(st, prev_state);
+		__cpuhp_kick_ap(st);
 	}
 
 out:
@@ -754,11 +917,15 @@ out:
 	cpu_maps_update_done();
 	return err;
 }
+
 int cpu_down(unsigned int cpu)
 {
 	return do_cpu_down(cpu, CPUHP_OFFLINE);
 }
 EXPORT_SYMBOL(cpu_down);
+
+#else
+#define takedown_cpu		NULL
 #endif /*CONFIG_HOTPLUG_CPU*/
 
 /**
@@ -772,11 +939,16 @@ void notify_cpu_starting(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
 	enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
+	int ret;
 
 	rcu_cpu_starting(cpu);	/* Enables RCU usage on this CPU. */
 	while (st->state < target) {
 		st->state++;
-		cpuhp_invoke_callback(cpu, st->state, true, NULL);
+		ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
+		/*
+		 * STARTING must not fail!
+		 */
+		WARN_ON_ONCE(ret);
 	}
 }
 
@@ -794,7 +966,7 @@ void cpuhp_online_idle(enum cpuhp_state state)
 		return;
 
 	st->state = CPUHP_AP_ONLINE_IDLE;
-	complete(&st->done);
+	complete_ap_thread(st, true);
 }
 
 /* Requires cpu_add_remove_lock to be held */
@@ -829,7 +1001,7 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
 
 	cpuhp_tasks_frozen = tasks_frozen;
 
-	st->target = target;
+	cpuhp_set_state(st, target);
 	/*
 	 * If the current CPU state is in the range of the AP hotplug thread,
 	 * then we need to kick the thread once more.
@@ -1296,6 +1468,10 @@ static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
 	struct cpuhp_step *sp = cpuhp_get_step(state);
 	int ret;
 
+	/*
+	 * If there's nothing to do, we done.
+	 * Relies on the union for multi_instance.
+	 */
 	if ((bringup && !sp->startup.single) ||
 	    (!bringup && !sp->teardown.single))
 		return 0;
@@ -1307,9 +1483,9 @@ static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
 	if (cpuhp_is_ap_state(state))
 		ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node);
 	else
-		ret = cpuhp_invoke_callback(cpu, state, bringup, node);
+		ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
 #else
-	ret = cpuhp_invoke_callback(cpu, state, bringup, node);
+	ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
 #endif
 	BUG_ON(ret && !bringup);
 	return ret;
@@ -1641,9 +1817,55 @@ static ssize_t show_cpuhp_target(struct device *dev,
 }
 static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target);
 
+
+static ssize_t write_cpuhp_fail(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+	struct cpuhp_step *sp;
+	int fail, ret;
+
+	ret = kstrtoint(buf, 10, &fail);
+	if (ret)
+		return ret;
+
+	/*
+	 * Cannot fail STARTING/DYING callbacks.
+	 */
+	if (cpuhp_is_atomic_state(fail))
+		return -EINVAL;
+
+	/*
+	 * Cannot fail anything that doesn't have callbacks.
+	 */
+	mutex_lock(&cpuhp_state_mutex);
+	sp = cpuhp_get_step(fail);
+	if (!sp->startup.single && !sp->teardown.single)
+		ret = -EINVAL;
+	mutex_unlock(&cpuhp_state_mutex);
+	if (ret)
+		return ret;
+
+	st->fail = fail;
+
+	return count;
+}
+
+static ssize_t show_cpuhp_fail(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+
+	return sprintf(buf, "%d\n", st->fail);
+}
+
+static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail);
+
 static struct attribute *cpuhp_cpu_attrs[] = {
 	&dev_attr_state.attr,
 	&dev_attr_target.attr,
+	&dev_attr_fail.attr,
 	NULL
 };
 
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index af71a84e12ee..f684d8e5fa2b 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -412,6 +412,19 @@ err:
 	return NULL;
 }
 
+static bool __always_inline rb_need_aux_wakeup(struct ring_buffer *rb)
+{
+	if (rb->aux_overwrite)
+		return false;
+
+	if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) {
+		rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark);
+		return true;
+	}
+
+	return false;
+}
+
 /*
  * Commit the data written by hardware into the ring buffer by adjusting
  * aux_head and posting a PERF_RECORD_AUX into the perf buffer. It is the
@@ -451,10 +464,8 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
 	}
 
 	rb->user_page->aux_head = rb->aux_head;
-	if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) {
+	if (rb_need_aux_wakeup(rb))
 		wakeup = true;
-		rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark);
-	}
 
 	if (wakeup) {
 		if (handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)
@@ -484,9 +495,8 @@ int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size)
 	rb->aux_head += size;
 
 	rb->user_page->aux_head = rb->aux_head;
-	if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) {
+	if (rb_need_aux_wakeup(rb)) {
 		perf_output_wakeup(handle);
-		rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark);
 		handle->wakeup = rb->aux_wakeup + rb->aux_watermark;
 	}
 
diff --git a/kernel/exit.c b/kernel/exit.c
index 3481ababd06a..f2cd53e92147 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1600,12 +1600,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
 	struct waitid_info info = {.status = 0};
 	long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
 	int signo = 0;
+
 	if (err > 0) {
 		signo = SIGCHLD;
 		err = 0;
-	}
-
-	if (!err) {
 		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
 			return -EFAULT;
 	}
@@ -1723,16 +1721,15 @@ COMPAT_SYSCALL_DEFINE5(waitid,
 	if (err > 0) {
 		signo = SIGCHLD;
 		err = 0;
-	}
-
-	if (!err && uru) {
-		/* kernel_waitid() overwrites everything in ru */
-		if (COMPAT_USE_64BIT_TIME)
-			err = copy_to_user(uru, &ru, sizeof(ru));
-		else
-			err = put_compat_rusage(&ru, uru);
-		if (err)
-			return -EFAULT;
+		if (uru) {
+			/* kernel_waitid() overwrites everything in ru */
+			if (COMPAT_USE_64BIT_TIME)
+				err = copy_to_user(uru, &ru, sizeof(ru));
+			else
+				err = put_compat_rusage(&ru, uru);
+			if (err)
+				return -EFAULT;
+		}
 	}
 
 	if (!infop)
diff --git a/kernel/extable.c b/kernel/extable.c
index 38c2412401a1..9aa1cc41ecf7 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -102,15 +102,7 @@ int core_kernel_data(unsigned long addr)
 
 int __kernel_text_address(unsigned long addr)
 {
-	if (core_kernel_text(addr))
-		return 1;
-	if (is_module_text_address(addr))
-		return 1;
-	if (is_ftrace_trampoline(addr))
-		return 1;
-	if (is_kprobe_optinsn_slot(addr) || is_kprobe_insn_slot(addr))
-		return 1;
-	if (is_bpf_text_address(addr))
+	if (kernel_text_address(addr))
 		return 1;
 	/*
 	 * There might be init symbols in saved stacktraces.
@@ -127,17 +119,42 @@ int __kernel_text_address(unsigned long addr)
 
 int kernel_text_address(unsigned long addr)
 {
+	bool no_rcu;
+	int ret = 1;
+
 	if (core_kernel_text(addr))
 		return 1;
+
+	/*
+	 * If a stack dump happens while RCU is not watching, then
+	 * RCU needs to be notified that it requires to start
+	 * watching again. This can happen either by tracing that
+	 * triggers a stack trace, or a WARN() that happens during
+	 * coming back from idle, or cpu on or offlining.
+	 *
+	 * is_module_text_address() as well as the kprobe slots
+	 * and is_bpf_text_address() require RCU to be watching.
+	 */
+	no_rcu = !rcu_is_watching();
+
+	/* Treat this like an NMI as it can happen anywhere */
+	if (no_rcu)
+		rcu_nmi_enter();
+
 	if (is_module_text_address(addr))
-		return 1;
+		goto out;
 	if (is_ftrace_trampoline(addr))
-		return 1;
+		goto out;
 	if (is_kprobe_optinsn_slot(addr) || is_kprobe_insn_slot(addr))
-		return 1;
+		goto out;
 	if (is_bpf_text_address(addr))
-		return 1;
-	return 0;
+		goto out;
+	ret = 0;
+out:
+	if (no_rcu)
+		rcu_nmi_exit();
+
+	return ret;
 }
 
 /*
diff --git a/kernel/futex.c b/kernel/futex.c
index 3d38eaf05492..0518a0bfc746 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -821,8 +821,6 @@ static void get_pi_state(struct futex_pi_state *pi_state)
 /*
  * Drops a reference to the pi_state object and frees or caches it
  * when the last reference is gone.
- *
- * Must be called with the hb lock held.
  */
 static void put_pi_state(struct futex_pi_state *pi_state)
 {
@@ -837,16 +835,22 @@ static void put_pi_state(struct futex_pi_state *pi_state)
 	 * and has cleaned up the pi_state already
 	 */
 	if (pi_state->owner) {
-		raw_spin_lock_irq(&pi_state->owner->pi_lock);
-		list_del_init(&pi_state->list);
-		raw_spin_unlock_irq(&pi_state->owner->pi_lock);
+		struct task_struct *owner;
 
-		rt_mutex_proxy_unlock(&pi_state->pi_mutex, pi_state->owner);
+		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		owner = pi_state->owner;
+		if (owner) {
+			raw_spin_lock(&owner->pi_lock);
+			list_del_init(&pi_state->list);
+			raw_spin_unlock(&owner->pi_lock);
+		}
+		rt_mutex_proxy_unlock(&pi_state->pi_mutex, owner);
+		raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 	}
 
-	if (current->pi_state_cache)
+	if (current->pi_state_cache) {
 		kfree(pi_state);
-	else {
+	} else {
 		/*
 		 * pi_state->list is already empty.
 		 * clear pi_state->owner.
@@ -907,13 +911,14 @@ void exit_pi_state_list(struct task_struct *curr)
 		raw_spin_unlock_irq(&curr->pi_lock);
 
 		spin_lock(&hb->lock);
-
-		raw_spin_lock_irq(&curr->pi_lock);
+		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		raw_spin_lock(&curr->pi_lock);
 		/*
 		 * We dropped the pi-lock, so re-check whether this
 		 * task still owns the PI-state:
 		 */
 		if (head->next != next) {
+			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
 			spin_unlock(&hb->lock);
 			continue;
 		}
@@ -922,9 +927,10 @@ void exit_pi_state_list(struct task_struct *curr)
 		WARN_ON(list_empty(&pi_state->list));
 		list_del_init(&pi_state->list);
 		pi_state->owner = NULL;
-		raw_spin_unlock_irq(&curr->pi_lock);
+		raw_spin_unlock(&curr->pi_lock);
 
 		get_pi_state(pi_state);
+		raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 		spin_unlock(&hb->lock);
 
 		rt_mutex_futex_unlock(&pi_state->pi_mutex);
@@ -1208,6 +1214,10 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key,
 
 	WARN_ON(!list_empty(&pi_state->list));
 	list_add(&pi_state->list, &p->pi_state_list);
+	/*
+	 * Assignment without holding pi_state->pi_mutex.wait_lock is safe
+	 * because there is no concurrency as the object is not published yet.
+	 */
 	pi_state->owner = p;
 	raw_spin_unlock_irq(&p->pi_lock);
 
@@ -2878,6 +2888,7 @@ retry:
 		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
 		spin_unlock(&hb->lock);
 
+		/* drops pi_state->pi_mutex.wait_lock */
 		ret = wake_futex_pi(uaddr, uval, pi_state);
 
 		put_pi_state(pi_state);
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index f7086b78ad6e..5270a54b9fa4 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -322,7 +322,6 @@ int __irq_alloc_domain_generic_chips(struct irq_domain *d, int irqs_per_chip,
 		/* Calc pointer to the next generic chip */
 		tmp += sizeof(*gc) + num_ct * sizeof(struct irq_chip_type);
 	}
-	d->name = name;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__irq_alloc_domain_generic_chips);
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 02f660666ab8..1fefe6dcafd7 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -613,6 +613,33 @@ struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 	DEFINE_WAKE_Q(wake_q);
 
 	/*
+	* __rwsem_down_write_failed_common(sem)
+	*   rwsem_optimistic_spin(sem)
+	*     osq_unlock(sem->osq)
+	*   ...
+	*   atomic_long_add_return(&sem->count)
+	*
+	*      - VS -
+	*
+	*              __up_write()
+	*                if (atomic_long_sub_return_release(&sem->count) < 0)
+	*                  rwsem_wake(sem)
+	*                    osq_is_locked(&sem->osq)
+	*
+	* And __up_write() must observe !osq_is_locked() when it observes the
+	* atomic_long_add_return() in order to not miss a wakeup.
+	*
+	* This boils down to:
+	*
+	* [S.rel] X = 1                [RmW] r0 = (Y += 0)
+	*         MB                         RMB
+	* [RmW]   Y += 1               [L]   r1 = X
+	*
+	* exists (r0=1 /\ r1=0)
+	*/
+	smp_rmb();
+
+	/*
 	 * If a spinner is present, it is not necessary to do the wakeup.
 	 * Try to do wakeup only if the trylock succeeds to minimize
 	 * spinlock contention which may introduce too much delay in the
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1250e4bd4b85..0c44c7b42e6d 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -882,6 +882,11 @@ void rcu_irq_exit(void)
 
 	RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_irq_exit() invoked with irqs enabled!!!");
 	rdtp = this_cpu_ptr(&rcu_dynticks);
+
+	/* Page faults can happen in NMI handlers, so check... */
+	if (READ_ONCE(rdtp->dynticks_nmi_nesting))
+		return;
+
 	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
 		     rdtp->dynticks_nesting < 1);
 	if (rdtp->dynticks_nesting <= 1) {
@@ -1015,6 +1020,11 @@ void rcu_irq_enter(void)
 
 	RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_irq_enter() invoked with irqs enabled!!!");
 	rdtp = this_cpu_ptr(&rcu_dynticks);
+
+	/* Page faults can happen in NMI handlers, so check... */
+	if (READ_ONCE(rdtp->dynticks_nmi_nesting))
+		return;
+
 	oldval = rdtp->dynticks_nesting;
 	rdtp->dynticks_nesting++;
 	WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 18a6966567da..d17c5da523a0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5166,6 +5166,28 @@ void sched_show_task(struct task_struct *p)
 	put_task_stack(p);
 }
 
+static inline bool
+state_filter_match(unsigned long state_filter, struct task_struct *p)
+{
+	/* no filter, everything matches */
+	if (!state_filter)
+		return true;
+
+	/* filter, but doesn't match */
+	if (!(p->state & state_filter))
+		return false;
+
+	/*
+	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
+	 * TASK_KILLABLE).
+	 */
+	if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
+		return false;
+
+	return true;
+}
+
+
 void show_state_filter(unsigned long state_filter)
 {
 	struct task_struct *g, *p;
@@ -5188,7 +5210,7 @@ void show_state_filter(unsigned long state_filter)
 		 */
 		touch_nmi_watchdog();
 		touch_all_softlockup_watchdogs();
-		if (!state_filter || (p->state & state_filter))
+		if (state_filter_match(state_filter, p))
 			sched_show_task(p);
 	}
 
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 01217fb5a5de..2f93e4a2d9f6 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -466,8 +466,6 @@ static char *task_group_path(struct task_group *tg)
 }
 #endif
 
-static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
-
 static void
 print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 {
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index c24579dfa7a1..bb3a38005b9c 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -473,14 +473,19 @@ static long seccomp_attach_filter(unsigned int flags,
 	return 0;
 }
 
+void __get_seccomp_filter(struct seccomp_filter *filter)
+{
+	/* Reference count is bounded by the number of total processes. */
+	refcount_inc(&filter->usage);
+}
+
 /* get_seccomp_filter - increments the reference count of the filter on @tsk */
 void get_seccomp_filter(struct task_struct *tsk)
 {
 	struct seccomp_filter *orig = tsk->seccomp.filter;
 	if (!orig)
 		return;
-	/* Reference count is bounded by the number of total processes. */
-	refcount_inc(&orig->usage);
+	__get_seccomp_filter(orig);
 }
 
 static inline void seccomp_filter_free(struct seccomp_filter *filter)
@@ -491,10 +496,8 @@ static inline void seccomp_filter_free(struct seccomp_filter *filter)
 	}
 }
 
-/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
-void put_seccomp_filter(struct task_struct *tsk)
+static void __put_seccomp_filter(struct seccomp_filter *orig)
 {
-	struct seccomp_filter *orig = tsk->seccomp.filter;
 	/* Clean up single-reference branches iteratively. */
 	while (orig && refcount_dec_and_test(&orig->usage)) {
 		struct seccomp_filter *freeme = orig;
@@ -503,6 +506,12 @@ void put_seccomp_filter(struct task_struct *tsk)
 	}
 }
 
+/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
+void put_seccomp_filter(struct task_struct *tsk)
+{
+	__put_seccomp_filter(tsk->seccomp.filter);
+}
+
 static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
 {
 	memset(info, 0, sizeof(*info));
@@ -1025,13 +1034,13 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
 	if (!data)
 		goto out;
 
-	get_seccomp_filter(task);
+	__get_seccomp_filter(filter);
 	spin_unlock_irq(&task->sighand->siglock);
 
 	if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
 		ret = -EFAULT;
 
-	put_seccomp_filter(task);
+	__put_seccomp_filter(filter);
 	return ret;
 
 out:
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6648fbbb8157..423554ad3610 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -367,7 +367,8 @@ static struct ctl_table kern_table[] = {
 		.data		= &sysctl_sched_time_avg,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 #ifdef CONFIG_SCHEDSTATS
 	{
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 2a685b45b73b..45a3928544ce 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -648,6 +648,12 @@ int blk_trace_startstop(struct request_queue *q, int start)
 }
 EXPORT_SYMBOL_GPL(blk_trace_startstop);
 
+/*
+ * When reading or writing the blktrace sysfs files, the references to the
+ * opened sysfs or device files should prevent the underlying block device
+ * from being removed. So no further delete protection is really needed.
+ */
+
 /**
  * blk_trace_ioctl: - handle the ioctls associated with tracing
  * @bdev:	the block device
@@ -665,7 +671,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 	if (!q)
 		return -ENXIO;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&q->blk_trace_mutex);
 
 	switch (cmd) {
 	case BLKTRACESETUP:
@@ -691,7 +697,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 		break;
 	}
 
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&q->blk_trace_mutex);
 	return ret;
 }
 
@@ -1727,7 +1733,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
 	if (q == NULL)
 		goto out_bdput;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&q->blk_trace_mutex);
 
 	if (attr == &dev_attr_enable) {
 		ret = sprintf(buf, "%u\n", !!q->blk_trace);
@@ -1746,7 +1752,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
 		ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
 
 out_unlock_bdev:
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&q->blk_trace_mutex);
 out_bdput:
 	bdput(bdev);
 out:
@@ -1788,7 +1794,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 	if (q == NULL)
 		goto out_bdput;
 
-	mutex_lock(&bdev->bd_mutex);
+	mutex_lock(&q->blk_trace_mutex);
 
 	if (attr == &dev_attr_enable) {
 		if (value)
@@ -1814,7 +1820,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
 	}
 
 out_unlock_bdev:
-	mutex_unlock(&bdev->bd_mutex);
+	mutex_unlock(&q->blk_trace_mutex);
 out_bdput:
 	bdput(bdev);
 out:
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index bac629af2285..c738e764e2a5 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -656,15 +656,6 @@ int trace_print_lat_context(struct trace_iterator *iter)
 	return !trace_seq_has_overflowed(s);
 }
 
-static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
-
-static int task_state_char(unsigned long state)
-{
-	int bit = state ? __ffs(state) + 1 : 0;
-
-	return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
-}
-
 /**
  * ftrace_find_event - find a registered event
  * @type: the type of event to look for
@@ -930,8 +921,8 @@ static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	T = task_state_char(field->next_state);
-	S = task_state_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
+	S = __task_state_to_char(field->prev_state);
 	trace_find_cmdline(field->next_pid, comm);
 	trace_seq_printf(&iter->seq,
 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
@@ -966,8 +957,8 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		S = task_state_char(field->prev_state);
-	T = task_state_char(field->next_state);
+		S = __task_state_to_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 			 field->prev_pid,
 			 field->prev_prio,
@@ -1002,8 +993,8 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		S = task_state_char(field->prev_state);
-	T = task_state_char(field->next_state);
+		S = __task_state_to_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
 
 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index ddec53b67646..0c331978b1a6 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -397,10 +397,10 @@ tracing_sched_switch_trace(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->prev_pid			= prev->pid;
 	entry->prev_prio		= prev->prio;
-	entry->prev_state		= prev->state;
+	entry->prev_state		= __get_task_state(prev);
 	entry->next_pid			= next->pid;
 	entry->next_prio		= next->prio;
-	entry->next_state		= next->state;
+	entry->next_state		= __get_task_state(next);
 	entry->next_cpu	= task_cpu(next);
 
 	if (!call_filter_check_discard(call, entry, buffer, event))
@@ -425,10 +425,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->prev_pid			= curr->pid;
 	entry->prev_prio		= curr->prio;
-	entry->prev_state		= curr->state;
+	entry->prev_state		= __get_task_state(curr);
 	entry->next_pid			= wakee->pid;
 	entry->next_prio		= wakee->prio;
-	entry->next_state		= wakee->state;
+	entry->next_state		= __get_task_state(wakee);
 	entry->next_cpu			= task_cpu(wakee);
 
 	if (!call_filter_check_discard(call, entry, buffer, event))
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index a4df67cbc711..49cb41412eec 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -96,23 +96,9 @@ check_stack(unsigned long ip, unsigned long *stack)
 	if (in_nmi())
 		return;
 
-	/*
-	 * There's a slight chance that we are tracing inside the
-	 * RCU infrastructure, and rcu_irq_enter() will not work
-	 * as expected.
-	 */
-	if (unlikely(rcu_irq_enter_disabled()))
-		return;
-
 	local_irq_save(flags);
 	arch_spin_lock(&stack_trace_max_lock);
 
-	/*
-	 * RCU may not be watching, make it see us.
-	 * The stack trace code uses rcu_sched.
-	 */
-	rcu_irq_enter();
-
 	/* In case another CPU set the tracer_frame on us */
 	if (unlikely(!frame_size))
 		this_size -= tracer_frame;
@@ -205,7 +191,6 @@ check_stack(unsigned long ip, unsigned long *stack)
 	}
 
  out:
-	rcu_irq_exit();
 	arch_spin_unlock(&stack_trace_max_lock);
 	local_irq_restore(flags);
 }