sched_ext: Defer sub_kset base put to scx_sched_free_rcu_work

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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: 411d3ef1a7 ("sched_ext: Unregister sub_kset on scheduler disable")
Signed-off-by: Tejun Heo <tj@kernel.org>

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Tejun Heo 2026-05-11 13:18:23 -10:00

parent b273b75b8d

commit cceb874eee

1 changed files with 4 additions and 2 deletions

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kernel/sched/ext.c

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