selftests: cpu-hotplug: fix case where CPUs offline > CPUs present

[ Upstream commit 2b531b6137834a55857a337ac17510d6436b6fbb ]

The cpu-hotplug test assumes that we can offline the maximum CPU as
described by /sys/devices/system/cpu/offline.  However, in the case
where the number of CPUs exceeds like kernel configuration then
the offline count can be greater than the present count and we end
up trying to test the offlining of a CPU that is not available to
offline.  Fix this by testing the maximum present CPU instead.

Also, the test currently offlines the CPU and does not online it,
so fix this by onlining the CPU after the test.

Fixes: d89dffa976bc ("fault-injection: add selftests for cpu and memory hotplug")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Shuah Khan <shuah@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
index f3a8933c12755f9593c1207a9d13d3d6a0d7999d..49ccd22933438bc875ad665a3f880dbe32b03a51 100755 (executable)
--- a/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
+++ b/tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
@@ -35,6 +35,10 @@ prerequisite()
                exit 0
        fi
 
+       present_cpus=`cat $SYSFS/devices/system/cpu/present`
+       present_max=${present_cpus##*-}
+       echo "present_cpus = $present_cpus present_max = $present_max"
+
        echo -e "\t Cpus in online state: $online_cpus"
 
        offline_cpus=`cat $SYSFS/devices/system/cpu/offline`
@@ -149,6 +153,8 @@ online_cpus=0
 online_max=0
 offline_cpus=0
 offline_max=0
+present_cpus=0
+present_max=0
 
 while getopts e:ahp: opt; do
        case $opt in
@@ -188,9 +194,10 @@ if [ $allcpus -eq 0 ]; then
        online_cpu_expect_success $online_max
 
        if [[ $offline_cpus -gt 0 ]]; then
-               echo -e "\t offline to online to offline: cpu $offline_max"
-               online_cpu_expect_success $offline_max
-               offline_cpu_expect_success $offline_max
+               echo -e "\t offline to online to offline: cpu $present_max"
+               online_cpu_expect_success $present_max
+               offline_cpu_expect_success $present_max
+               online_cpu $present_max
        fi
        exit 0
 else