6.10-stable review patch. If anyone has any objections, please let me know.
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From: Waiman Long longman@redhat.com
commit 311a1bdc44a8e06024df4fd3392be0dfc8298655 upstream.
Commit e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2") adds a user writable cpuset.cpus.exclusive file for setting exclusive CPUs to be used for the creation of partitions. Since then effective_xcpus depends on both the cpuset.cpus and cpuset.cpus.exclusive setting. If cpuset.cpus.exclusive is set, effective_xcpus will depend only on cpuset.cpus.exclusive. When it is not set, effective_xcpus will be set according to the cpuset.cpus value when the cpuset becomes a valid partition root.
When cpuset.cpus is being cleared by the user, effective_xcpus should only be cleared when cpuset.cpus.exclusive is not set. However, that is not currently the case.
# cd /sys/fs/cgroup/ # mkdir test # echo +cpuset > cgroup.subtree_control # cd test # echo 3 > cpuset.cpus.exclusive # cat cpuset.cpus.exclusive.effective 3 # echo > cpuset.cpus # cat cpuset.cpus.exclusive.effective // was cleared
Fix it by clearing effective_xcpus only if cpuset.cpus.exclusive is not set.
Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2") Cc: stable@vger.kernel.org # v6.7+ Reported-by: Chen Ridong chenridong@huawei.com Signed-off-by: Waiman Long longman@redhat.com Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/cgroup/cpuset.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2474,7 +2474,8 @@ static int update_cpumask(struct cpuset */ if (!*buf) { cpumask_clear(trialcs->cpus_allowed); - cpumask_clear(trialcs->effective_xcpus); + if (cpumask_empty(trialcs->exclusive_cpus)) + cpumask_clear(trialcs->effective_xcpus); } else { retval = cpulist_parse(buf, trialcs->cpus_allowed); if (retval < 0)