diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index c82b805b112b..2a7a0c579c9a 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2137,6 +2137,25 @@ static void compute_partition_effective_cpumask(struct cpuset *cs,
 	rcu_read_unlock();
 }
 
+/*
+ * ancestor_partition - Find and return the closest valid partition root ancestor
+ * @cs: the current cpuset
+ *
+ * Return: The closet partition root ancestor cpuset
+ */
+static struct cpuset *ancestor_partition(struct cpuset *cs)
+{
+	struct cpuset *ancestor = parent_cs(cs);
+
+	/*
+	 * The top_cpuset is always a valid partition root which will stop
+	 * the loop if it is reached.
+	 */
+	while (!is_partition_valid(ancestor))
+		ancestor = parent_cs(ancestor);
+	return ancestor;
+}
+
 /*
  * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
  * @cs:  the cpuset to consider
@@ -2229,7 +2248,10 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
 		 * cpuset if the parent's effective_cpus changes.
 		 */
 		if ((cp != cs) && old_prs) {
-			switch (parent->partition_root_state) {
+			int parent_prs = parent->partition_root_state;
+			struct cpumask *del_cpus = NULL;
+
+			switch (parent_prs) {
 			case PRS_ROOT:
 			case PRS_ISOLATED:
 				update_parent = true;
@@ -2237,12 +2259,37 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
 
 			default:
 				/*
-				 * When parent is not a partition root or is
-				 * invalid, child partition roots become
-				 * invalid too.
+				 * When parent is not a valid partition root,
+				 * child partition roots become invalid too.
+				 *
+				 * For a to be invalidated isolated partition,
+				 * its isolated CPUs may or may not need to be
+				 * removed from isolated_cpus depending on if
+				 * its closest partition root ancestor is a root
+				 * or isolated partition. With a PRS_ISOLATED
+				 * ancestor, the CPUs are checked against its
+				 * effective xcpus to see if any of them needed
+				 * to be removed.
 				 */
 				if (is_partition_valid(cp))
-					new_prs = -cp->partition_root_state;
+					new_prs = -old_prs;
+
+				if (old_prs == PRS_ISOLATED) {
+					struct cpuset *ancestor = ancestor_partition(cp);
+
+					if (ancestor->partition_root_state == PRS_ROOT)
+						del_cpus = cp->effective_xcpus;
+					else if (cpumask_andnot(tmp->delmask,
+								cp->effective_xcpus,
+								ancestor->effective_xcpus))
+						del_cpus = tmp->delmask;
+
+					if (del_cpus) {
+						spin_lock_irq(&callback_lock);
+						isolated_cpus_update(old_prs, new_prs, del_cpus);
+						spin_unlock_irq(&callback_lock);
+					}
+				}
 				WRITE_ONCE(cp->prs_err,
 					   is_partition_invalid(parent)
 					   ? PERR_INVPARENT : PERR_NOTPART);
diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 7efd5e645767..f1dda27b1394 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -292,9 +292,9 @@ TEST_MATRIX=(
 								       A1:P0|A2:P2|A3:P1 2-4|2-3"
 	"   C0-4    C1-4  C2-4     .    X2-4  X2-4:P2 X3-4:P1   .    0 A1:0-1|A2:2|A3:3-4 \
 								       A1:P0|A2:P2|A3:P1 2"
-	" C0-4:X2-4 C1-4:X2-4:P2 C2-4:X4:P1 \
-				   .      .      X5      .      .    0 A1:0-4|A2:1-4|A3:2-4 \
-								       A1:P0|A2:P-2|A3:P-1 ."
+	" C1-4:X2-4 C2-4:X3-4:P1 C3-4:X4:P2 \
+				   .      .      X5      .      .    0 A1:1-4|A2:2-4|A3:3-4 \
+								       A1:P0|A2:P-1|A3:P-2 ."
 	" C0-4:X2-4 C1-4:X2-4:P2 C2-4:X4:P1 \
 				   .      .      .      X1      .    0 A1:0-1|A2:2-4|A3:2-4 \
 								       A1:P0|A2:P2|A3:P-1 2-4"