diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 585a982249ad..71644482faa7 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -478,10 +478,10 @@ static inline bool partition_is_populated(struct cpuset *cs,
 
 	rcu_read_lock();
 	cpuset_for_each_descendant_pre(cp, pos_css, cs) {
-		if (cp == cs || cp == excluded_child)
+		if (cp == cs)
 			continue;
 
-		if (is_partition_valid(cp)) {
+		if (cp == excluded_child || is_partition_valid(cp)) {
 			pos_css = css_rightmost_descendant(pos_css);
 			continue;
 		}
diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index d04aad697b96..9978c560b398 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -452,6 +452,9 @@ TEST_MATRIX=(
 	# Enabling partition with child cpusets is allowed
 	"   C0-1    C1      .    C2-3    P1      .      .      .     0 A1:0-1|A2:1 A1:P1"
 
+	# Tasks below a new partition belong to it, not to its parent.
+	" C1-2:P1 C1-2 C1-2:T    .      .      P1     .      .     0 A1:|A2:1-2|A3:1-2 A1:P1|A2:P1"
+
 	# A partition root with non-partition root parent is invalid| but it
 	# can be made valid if its parent becomes a partition root too.
 	"   C0-1    C1      .    C2-3     .      P2     .      .     0 A1:0-1|A2:1 A1:P0|A2:P-2"