diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 8380fd9d76bd..da8f7b920178 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -526,6 +526,7 @@ write_cpu_online()
 	CPU=${1%=*}
 	VAL=${1#*=}
 	CPUFILE=//sys/devices/system/cpu/cpu${CPU}/online
+	echo $VAL > $CPUFILE || return 1
 	if [[ $VAL -eq 0 ]]
 	then
 		OFFLINE_CPUS="$OFFLINE_CPUS $CPU"
@@ -535,7 +536,6 @@ write_cpu_online()
 					sort | uniq -u)
 		}
 	fi
-	echo $VAL > $CPUFILE
 	pause 0.05
 }
 
@@ -603,7 +603,8 @@ set_ctrl_state()
 			eval $COMM $REDIRECT
 			;;
 		    O*) VAL=${CMD#?}
-			write_cpu_online $VAL
+			COMM="write_cpu_online $VAL"
+			eval $COMM $REDIRECT
 			;;
 		    T*) COMM="echo 0 > $TFILE"
 			eval $COMM $REDIRECT