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authorWaiman Long <longman@redhat.com>2023-03-17 11:15:05 -0400
committerTejun Heo <tj@kernel.org>2023-03-29 08:37:07 -1000
commit292fd843de26c551856e66faf134512c52dd78b4 (patch)
treec64dd23e8acc0f98aef4bf91310c321ec18390ee /kernel/cgroup
parentfcdb1eda5302599045bb366e679cccb4216f3873 (diff)
cgroup/cpuset: Fix partition root's cpuset.cpus update bug
It was found that commit 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") introduced a bug that corrupted "cpuset.cpus" of a partition root when it was updated. It is because the tmp->new_cpus field of the passed tmp parameter of update_parent_subparts_cpumask() should not be used at all as it contains important cpumask data that should not be overwritten. Fix it by using tmp->addmask instead. Also update update_cpumask() to make sure that trialcs->cpu_allowed will not be corrupted until it is no longer needed. Fixes: 7a2127e66a00 ("cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task") Signed-off-by: Waiman Long <longman@redhat.com> Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
-rw-r--r--kernel/cgroup/cpuset.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 636f1c682ac0..f310915d1257 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1513,7 +1513,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
spin_unlock_irq(&callback_lock);
if (adding || deleting)
- update_tasks_cpumask(parent, tmp->new_cpus);
+ update_tasks_cpumask(parent, tmp->addmask);
/*
* Set or clear CS_SCHED_LOAD_BALANCE when partcmd_update, if necessary.
@@ -1770,10 +1770,13 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
/*
* Use the cpumasks in trialcs for tmpmasks when they are pointers
* to allocated cpumasks.
+ *
+ * Note that update_parent_subparts_cpumask() uses only addmask &
+ * delmask, but not new_cpus.
*/
tmp.addmask = trialcs->subparts_cpus;
tmp.delmask = trialcs->effective_cpus;
- tmp.new_cpus = trialcs->cpus_allowed;
+ tmp.new_cpus = NULL;
#endif
retval = validate_change(cs, trialcs);
@@ -1838,6 +1841,11 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
}
spin_unlock_irq(&callback_lock);
+#ifdef CONFIG_CPUMASK_OFFSTACK
+ /* Now trialcs->cpus_allowed is available */
+ tmp.new_cpus = trialcs->cpus_allowed;
+#endif
+
/* effective_cpus will be updated here */
update_cpumasks_hier(cs, &tmp, false);