From: Waiman Long <longman@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx # v6.7+
Reported-by: Chen Ridong <chenridong@xxxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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)
Patches currently in stable-queue which might be from longman@xxxxxxxxxx are
queue-6.10/cgroup-cpuset-fix-panic-caused-by-partcmd_update.patch
queue-6.10/cgroup-cpuset-clear-effective_xcpus-on-cpus_allowed-clearing-only-if-cpus.exclusive-not-set.patch
queue-6.10/mm-memory-failure-use-raw_spinlock_t-in-struct-memory_failure_cpu.patch
