diff --git a/kernel/sched/walt/core_ctl.c b/kernel/sched/walt/core_ctl.c
index 52e78df1cd2d..6cee4ad08efd 100644
--- a/kernel/sched/walt/core_ctl.c
+++ b/kernel/sched/walt/core_ctl.c
@@ -85,6 +85,7 @@ ATOMIC_NOTIFIER_HEAD(core_ctl_notifier);
 static unsigned int last_nr_big;
 
 static unsigned int get_active_cpu_count(const struct cluster_data *cluster);
+static void __ref do_core_ctl(void);
 
 /* ========================= sysfs interface =========================== */
 
@@ -995,7 +996,7 @@ void core_ctl_check(u64 window_start)
 		wakeup |= eval_need(cluster);
 
 	if (wakeup)
-		wake_up_core_ctl_thread();
+		do_core_ctl();
 	core_ctl_call_notifier();
 }
 
diff --git a/kernel/sched/walt/walt_halt.c b/kernel/sched/walt/walt_halt.c
index c622115adae4..abf9b328c9b6 100644
--- a/kernel/sched/walt/walt_halt.c
+++ b/kernel/sched/walt/walt_halt.c
@@ -15,7 +15,8 @@
 /* if a cpu is halting */
 struct cpumask __cpu_halt_mask;
 
-static DEFINE_MUTEX(halt_lock);
+/* spin lock to allow calling from non-preemptible context */
+static DEFINE_RAW_SPINLOCK(halt_lock);
 
 struct halt_cpu_state {
 	u64		last_halt;
@@ -359,8 +360,9 @@ int walt_halt_cpus(struct cpumask *cpus)
 {
 	int ret = 0;
 	cpumask_t requested_cpus;
+	unsigned long flags;
 
-	mutex_lock(&halt_lock);
+	raw_spin_lock_irqsave(&halt_lock, flags);
 
 	cpumask_copy(&requested_cpus, cpus);
 
@@ -380,7 +382,7 @@ int walt_halt_cpus(struct cpumask *cpus)
 	else
 		update_ref_counts(&requested_cpus, true);
 unlock:
-	mutex_unlock(&halt_lock);
+	raw_spin_unlock_irqrestore(&halt_lock, flags);
 
 	return ret;
 }
@@ -397,8 +399,9 @@ int walt_start_cpus(struct cpumask *cpus)
 {
 	int ret = 0;
 	cpumask_t requested_cpus;
+	unsigned long flags;
 
-	mutex_lock(&halt_lock);
+	raw_spin_lock_irqsave(&halt_lock, flags);
 	cpumask_copy(&requested_cpus, cpus);
 	update_ref_counts(&requested_cpus, false);
 
@@ -414,7 +417,7 @@ int walt_start_cpus(struct cpumask *cpus)
 		update_ref_counts(&requested_cpus, true);
 	}
 
-	mutex_unlock(&halt_lock);
+	raw_spin_unlock_irqrestore(&halt_lock, flags);
 
 	return ret;
 }