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| author | Tejun Heo <tj@kernel.org> | 2026-05-11 13:18:23 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-05-12 11:28:56 -1000 |
| commit | cceb874eee46fe4b3d3c6c496f19125d9a3a9a8f (patch) | |
| tree | 0e95ed7f1013afcc60734dd84ceac95ca84c8b6a /kernel | |
| parent | b273b75b8d677aea06dd06d80b61b3bb06e94680 (diff) | |
| download | linux-cceb874eee46fe4b3d3c6c496f19125d9a3a9a8f.tar.gz linux-cceb874eee46fe4b3d3c6c496f19125d9a3a9a8f.zip | |
sched_ext: Defer sub_kset base put to scx_sched_free_rcu_work
scx_sub_enable_workfn() pins parent->kobj before dropping scx_sched_lock,
but that does not pin parent->sub_kset. Concurrent disable can
kset_unregister and free sub_kset before scx_alloc_and_add_sched()
dereferences it.
Split sub_kset teardown: kobject_del() at disable keeps sysfs removal; defer
kobject_put() to scx_sched_free_rcu_work so the memory survives. A racing
child sees state_in_sysfs=0 with valid memory, sysfs_create_dir() fails, and
the existing exit_kind gate in scx_link_sched() turns it away with -ENOENT.
Fixes: 411d3ef1a705 ("sched_ext: Unregister sub_kset on scheduler disable")
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 6d69ba29cfd7..23f7b3f63b09 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4821,6 +4821,8 @@ static void scx_sched_free_rcu_work(struct work_struct *work) kfree(sch->cgrp_path); if (sch_cgroup(sch)) cgroup_put(sch_cgroup(sch)); + if (sch->sub_kset) + kobject_put(&sch->sub_kset->kobj); #endif /* CONFIG_EXT_SUB_SCHED */ for_each_possible_cpu(cpu) { @@ -5861,7 +5863,7 @@ static void scx_sub_disable(struct scx_sched *sch) if (sch->ops.exit) SCX_CALL_OP(sch, exit, NULL, sch->exit_info); if (sch->sub_kset) - kset_unregister(sch->sub_kset); + kobject_del(&sch->sub_kset->kobj); kobject_del(&sch->kobj); } #else /* CONFIG_EXT_SUB_SCHED */ @@ -5995,7 +5997,7 @@ static void scx_root_disable(struct scx_sched *sch) */ #ifdef CONFIG_EXT_SUB_SCHED if (sch->sub_kset) - kset_unregister(sch->sub_kset); + kobject_del(&sch->sub_kset->kobj); #endif kobject_del(&sch->kobj); |