diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index f1a185ab5fbc7e..0c68ace02e4b2e 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3342,6 +3342,12 @@ static s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu,
 
 	*found = false;
 
+
+	/*
+	 * This is necessary to protect llc_cpus.
+	 */
+	rcu_read_lock();
+
 	/*
 	 * Determine the scheduling domain only if the task is allowed to run
 	 * on all CPUs.
@@ -3476,9 +3482,12 @@ static s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu,
 	if (cpu >= 0)
 		goto cpu_found;
 
+	rcu_read_unlock();
 	return prev_cpu;
 
 cpu_found:
+	rcu_read_unlock();
+
 	*found = true;
 	return cpu;
 }