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charset="utf-8" When a task leaves the BPF scheduler's control, p->scx.dsq_vtime and p->scx.slice keep whatever values they last held. The slice value is core-managed and is refilled on the next enqueue, but dsq_vtime is owned by the BPF scheduler and is never cleared by the core, so a task that leaves SCX and later returns carries a stale dsq_vtime across the round-trip. The stale values are also visible to other SCX schedulers that inspect the scx fields of non-SCX tasks. Fix this by resetting both dsq_vtime and slice in scx_disable_task(), after ops.disable(), so the BPF scheduler can still observe the task's final values and non-SCX tasks do not retain stale SCX state. Signed-off-by: Andrea Righi --- Changes in v2: - Reset SCX values in scx_disable_task() (Sashiko) - Link to v1: https://lore.kernel.org/all/20260608134908.3232097-1-arighi@= nvidia.com/ kernel/sched/ext.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 8e88a25bc602f..01b4f29de073c 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -3659,6 +3659,13 @@ static void scx_disable_task(struct scx_sched *sch, = struct task_struct *p) SCX_CALL_OP_TASK(sch, disable, rq, p); scx_set_task_state(p, SCX_TASK_READY); =20 + /* + * Reset the SCX-managed fields when @p leaves the BPF scheduler's + * control, after ops.disable() has observed their final values. + */ + p->scx.dsq_vtime =3D 0; + p->scx.slice =3D 0; + /* * Verify the task is not in BPF scheduler's custody. If flag * transitions are consistent, the flag should always be clear --=20 2.54.0