The helper function _offline_cpu() sets a value to RESTORE_CPUS_ONLINE.
However, the commit bd6b882b2650 ("block/008: check CPU offline failure
due to many IRQs") put _offline_cpu() call in sub-shell, then the set
value to RESTORE_CPUS_ONLINE no longer affects function caller's
environment. This resulted in off-lined CPUs not restored by _cleanup()
when the test case block/008 calls only _offline_cpu() and does not call
_online_cpu().
To fix the issue, set RESTORE_CPUS_ONLINE in _have_cpu_hotplug() in
place of _offline_cpu(). _have_cpu_hotplug() is less likely to be called
in sub-shell. In same manner, do not set RESTORE_CPUS_ONLINE in
_online_cpu() either. Check that RESTORE_CPUS_ONLINE is set in
_offline_cpu() to avoid unexpected CPUs left off-lined. This check also
avoids a shellcheck warning.
Fixes: bd6b882b2650 ("block/008: check CPU offline failure due to many IRQs")
Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
Changes from v1:
* Change fix approach: fix _offline_cpu() instaed of block/008 test script.
common/cpuhotplug | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/common/cpuhotplug b/common/cpuhotplug
index 7facd0d..e91c3bc 100644
--- a/common/cpuhotplug
+++ b/common/cpuhotplug
@@ -27,17 +27,20 @@ _have_cpu_hotplug() {
SKIP_REASONS+=("CPU hotplugging is not supported")
return 1
fi
+
+ RESTORE_CPUS_ONLINE=1
return 0
}
_online_cpu() {
- # shellcheck disable=SC2034
- RESTORE_CPUS_ONLINE=1
echo 1 > "/sys/devices/system/cpu/cpu$1/online"
}
_offline_cpu() {
- # shellcheck disable=SC2034
- RESTORE_CPUS_ONLINE=1
+ if [[ -z ${RESTORE_CPUS_ONLINE} ]]; then
+ echo "offlining cpu but RESTORE_CPUS_ONLINE is not set"
+ return 1
+ fi
+
echo 0 > "/sys/devices/system/cpu/cpu$1/online"
}
--
2.36.1
