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-rw-r--r--kernel/sched/ext.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index cc5df32db8ff..8a2a90659c65 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1495,11 +1495,13 @@ static void dispatch_enqueue(struct scx_sched *sch, struct rq *rq,
if (!(dsq->id & SCX_DSQ_FLAG_BUILTIN))
rcu_assign_pointer(dsq->first_task, p);
} else {
- bool was_empty;
-
- was_empty = list_empty(&dsq->list);
+ /*
+ * dsq->list can contain parked BPF iterator cursors, so
+ * list_empty() here isn't a reliable proxy for "no real
+ * task in the DSQ". Test dsq->first_task directly.
+ */
list_add_tail(&p->scx.dsq_list.node, &dsq->list);
- if (was_empty && !(dsq->id & SCX_DSQ_FLAG_BUILTIN))
+ if (!dsq->first_task && !(dsq->id & SCX_DSQ_FLAG_BUILTIN))
rcu_assign_pointer(dsq->first_task, p);
}
}