Promotion of kernel.lnx.4.4-161211.

CRs      Change ID                                   Subject
--------------------------------------------------------------------------------------------------------------
1092907   I6d73b8f246ae3754ab60984af198333fd284ae16   sched/core: Fix race condition in clearing hmp request
1078814   Ie28323cdabccdc64196fae25deb2f56dfbb5a0e7   ARM: dts: msm: enable the watchdog bark interrupt for sm
1094175   I34a3ad2da7f8e267f0d570c0329ac9b73a43309e   ARM: dts: msm: add qdss node support for msmtriton
1092907   I078d01e63860d1fc60fc96eb0c739c0f680ae983   sched/core: Prevent (user) space tasks from affining to
1096988   I34e3f586b99b6ff1af1d2323d4f272ee3cca7fa2   ARM: dts: msm: Configure MPM for qusb2phy_dpse_hv for ms
1080662   I42e448ecacad4781b460c4c989026307169ba1b5   mm: remove gup_flags FOLL_WRITE games from __get_user_pa
1091972   I9d7cc82c50c1b09610f5a4eac86af4617389f23f   ARM: dts: msm: Add BCL peripheral configs for pmfalcon
1092907   Id06151a8e34edab49ac76b4bffd50c132f0b792f   sched: Ensure proper task migration when a CPU is isolat
1098004   I7d96555573cfd6cca1ca56c877d78fde943f8100   sound: usb: Handle implicit feedback data endpoint prope
1091972   I0062f3b39f00ff2f0e74affcffbcf1afd89d3b2f   power: bcl: Add frequency mitigation as an optional prop
1099112   I014c823bcf2545f005205dde326a074eaa5d7a6a   clk: msm: clock-osm: don't use version register to enabl

Change-Id: Ie97cd9c7d2048e9e540056d4f5f121435a147d05
CRs-Fixed: 1098004, 1094175, 1078814, 1080662, 1092907, 1099112, 1096988, 1091972

2 files changed, 69 insertions, 26 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d7846edd7a79..ee708909dc17 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1248,15 +1248,16 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 		goto out;
 
 	cpumask_andnot(&allowed_mask, new_mask, cpu_isolated_mask);
+	cpumask_and(&allowed_mask, &allowed_mask, cpu_active_mask);
 
-	dest_cpu = cpumask_any_and(cpu_active_mask, &allowed_mask);
+	dest_cpu = cpumask_any(&allowed_mask);
 	if (dest_cpu >= nr_cpu_ids) {
-		dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
+		cpumask_and(&allowed_mask, cpu_active_mask, new_mask);
+		dest_cpu = cpumask_any(&allowed_mask);
 		if (dest_cpu >= nr_cpu_ids) {
 			ret = -EINVAL;
 			goto out;
 		}
-		cpumask_copy(&allowed_mask, new_mask);
 	}
 
 	do_set_cpus_allowed(p, new_mask);
@@ -4635,6 +4636,8 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 	cpumask_var_t cpus_allowed, new_mask;
 	struct task_struct *p;
 	int retval;
+	int dest_cpu;
+	cpumask_t allowed_mask;
 
 	rcu_read_lock();
 
@@ -4696,20 +4699,26 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 	}
 #endif
 again:
-	retval = __set_cpus_allowed_ptr(p, new_mask, true);
-
-	if (!retval) {
-		cpuset_cpus_allowed(p, cpus_allowed);
-		if (!cpumask_subset(new_mask, cpus_allowed)) {
-			/*
-			 * We must have raced with a concurrent cpuset
-			 * update. Just reset the cpus_allowed to the
-			 * cpuset's cpus_allowed
-			 */
-			cpumask_copy(new_mask, cpus_allowed);
-			goto again;
+	cpumask_andnot(&allowed_mask, new_mask, cpu_isolated_mask);
+	dest_cpu = cpumask_any_and(cpu_active_mask, &allowed_mask);
+	if (dest_cpu < nr_cpu_ids) {
+		retval = __set_cpus_allowed_ptr(p, new_mask, true);
+		if (!retval) {
+			cpuset_cpus_allowed(p, cpus_allowed);
+			if (!cpumask_subset(new_mask, cpus_allowed)) {
+				/*
+				 * We must have raced with a concurrent cpuset
+				 * update. Just reset the cpus_allowed to the
+				 * cpuset's cpus_allowed
+				 */
+				cpumask_copy(new_mask, cpus_allowed);
+				goto again;
+			}
 		}
+	} else {
+		retval = -EINVAL;
 	}
+
 out_free_new_mask:
 	free_cpumask_var(new_mask);
 out_free_cpus_allowed:
@@ -5455,6 +5464,37 @@ static struct task_struct fake_task = {
 };
 
 /*
+ * Remove a task from the runqueue and pretend that it's migrating. This
+ * should prevent migrations for the detached task and disallow further
+ * changes to tsk_cpus_allowed.
+ */
+static void
+detach_one_task(struct task_struct *p, struct rq *rq, struct list_head *tasks)
+{
+	lockdep_assert_held(&rq->lock);
+
+	p->on_rq = TASK_ON_RQ_MIGRATING;
+	deactivate_task(rq, p, 0);
+	list_add(&p->se.group_node, tasks);
+}
+
+static void attach_tasks(struct list_head *tasks, struct rq *rq)
+{
+	struct task_struct *p;
+
+	lockdep_assert_held(&rq->lock);
+
+	while (!list_empty(tasks)) {
+		p = list_first_entry(tasks, struct task_struct, se.group_node);
+		list_del_init(&p->se.group_node);
+
+		BUG_ON(task_rq(p) != rq);
+		activate_task(rq, p, 0);
+		p->on_rq = TASK_ON_RQ_QUEUED;
+	}
+}
+
+/*
  * Migrate all tasks (not pinned if pinned argument say so) from the rq,
  * sleeping tasks will be migrated by try_to_wake_up()->select_task_rq().
  *
@@ -5468,6 +5508,7 @@ static void migrate_tasks(struct rq *dead_rq, bool migrate_pinned_tasks)
 	struct task_struct *next, *stop = rq->stop;
 	int dest_cpu;
 	unsigned int num_pinned_kthreads = 1; /* this thread */
+	LIST_HEAD(tasks);
 	cpumask_t avail_cpus;
 
 	cpumask_andnot(&avail_cpus, cpu_online_mask, cpu_isolated_mask);
@@ -5492,12 +5533,10 @@ static void migrate_tasks(struct rq *dead_rq, bool migrate_pinned_tasks)
 
 	for (;;) {
 		/*
-		 * There's this thread running + pinned threads, bail when
-		 * that's the only remaining threads.
+		 * There's this thread running, bail when that's the only
+		 * remaining thread.
 		 */
-		if ((migrate_pinned_tasks && rq->nr_running == 1) ||
-		   (!migrate_pinned_tasks &&
-		    rq->nr_running <= num_pinned_kthreads))
+		if (rq->nr_running == 1)
 			break;
 
 		/*
@@ -5510,8 +5549,9 @@ static void migrate_tasks(struct rq *dead_rq, bool migrate_pinned_tasks)
 
 		if (!migrate_pinned_tasks && next->flags & PF_KTHREAD &&
 			!cpumask_intersects(&avail_cpus, &next->cpus_allowed)) {
-			lockdep_unpin_lock(&rq->lock);
+			detach_one_task(next, rq, &tasks);
 			num_pinned_kthreads += 1;
+			lockdep_unpin_lock(&rq->lock);
 			continue;
 		}
 
@@ -5559,6 +5599,9 @@ static void migrate_tasks(struct rq *dead_rq, bool migrate_pinned_tasks)
 	}
 
 	rq->stop = stop;
+
+	if (num_pinned_kthreads > 1)
+		attach_tasks(&tasks, rq);
 }
 
 static void set_rq_online(struct rq *rq);
@@ -5600,6 +5643,7 @@ int do_isolation_work_cpu_stop(void *data)
 	 */
 	nohz_balance_clear_nohz_mask(cpu);
 
+	clear_hmp_request(cpu);
 	local_irq_enable();
 	return 0;
 }
@@ -5724,7 +5768,6 @@ int sched_isolate_cpu(int cpu)
 
 	migrate_sync_cpu(cpu, cpumask_first(&avail_cpus));
 	stop_cpus(cpumask_of(cpu), do_isolation_work_cpu_stop, 0);
-	clear_hmp_request(cpu);
 
 	calc_load_migrate(rq);
 	update_max_interval();
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 12a04f30ef77..52edd6b158ed 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1970,11 +1970,11 @@ retry:
 		goto retry;
 	}
 
-	deactivate_task(rq, next_task, 0);
 	next_task->on_rq = TASK_ON_RQ_MIGRATING;
+	deactivate_task(rq, next_task, 0);
 	set_task_cpu(next_task, lowest_rq->cpu);
-	next_task->on_rq = TASK_ON_RQ_QUEUED;
 	activate_task(lowest_rq, next_task, 0);
+	next_task->on_rq = TASK_ON_RQ_QUEUED;
 	ret = 1;
 
 	resched_curr(lowest_rq);
@@ -2226,11 +2226,11 @@ static void pull_rt_task(struct rq *this_rq)
 
 			resched = true;
 
-			deactivate_task(src_rq, p, 0);
 			p->on_rq = TASK_ON_RQ_MIGRATING;
+			deactivate_task(src_rq, p, 0);
 			set_task_cpu(p, this_cpu);
-			p->on_rq = TASK_ON_RQ_QUEUED;
 			activate_task(this_rq, p, 0);
+			p->on_rq = TASK_ON_RQ_QUEUED;
 			/*
 			 * We continue with the search, just in
 			 * case there's an even higher prio task