[PATCH v3 1/8] sched/deadline: Ignore special tasks when rebuilding domains

[Juri Lelli]

SCHED_DEADLINE special tasks get a fake bandwidth that is only used to
make sure sleeping and priority inheritance 'work', but it is ignored
for runtime enforcement and admission control.

Be consistent with it also when rebuilding root domains.

Reported-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Tested-by: Waiman Long <longman@xxxxxxxxxx>
Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
---
 kernel/sched/deadline.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ff4df16b5186..1a041c1fc0d1 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2956,7 +2956,7 @@ void dl_add_task_root_domain(struct task_struct *p)
 	struct dl_bw *dl_b;
 
 	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
-	if (!dl_task(p)) {
+	if (!dl_task(p) || dl_entity_is_special(&p->dl)) {
 		raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
 		return;
 	}
-- 
2.48.1