On 8/9/2026 4:21 PM, Rui Qi wrote:
The cpuset partition root state selftest checks several CPU hotplug
transitions. If writing to a CPU online file fails, the helper still
runs pause afterwards and returns the status of pause instead of the
failed write.

This hides the real hotplug failure and can make later checks run
against expectations for a transition that never happened. Move the
write before the bookkeeping and return when it fails, so callers can
observe the hotplug error and the test does not record a CPU as offline
unless the offline operation actually succeeded.

Fixes: a8c52eba880a ("kselftest/cgroup: Add cpuset v2 partition root state 
test")
Signed-off-by: Rui Qi <[email protected]>
---
  tools/testing/selftests/cgroup/test_cpuset_prs.sh | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh 
b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 16c38eb11e63..a2f7208633bc 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -412,6 +412,7 @@ 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"
@@ -421,7 +422,6 @@ write_cpu_online()
                                        sort | uniq -u)
                }
        fi
-       echo $VAL > $CPUFILE
        pause 0.05
  }
@@ -493,6 +493,7 @@ set_ctrl_state()
                        eval $COMM $REDIRECT
                        ;;
                    O*) VAL=${CMD#?}
+                       COMM="write_cpu_online $VAL"
                        write_cpu_online $VAL
                        ;;
                    T*) COMM="echo 0 > $TFILE"

LGTM.

Reviewed-by: Ridong Chen <[email protected]>

--
Best regards
Ridong


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