sched: fix rt-bandwidth hotplug race
When we hot-unplug a cpu and rebuild the sched-domain, all cpus will be
detatched. Alex observed the case where a runqueue was stealing bandwidth
from an already disabled runqueue to satisfy its own needs.
Stop this by skipping over already disabled runqueues.
Reported-by: Alex Nixon <alex.nixon@citrix.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Alex Nixon <alex.nixon@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 6163e4c..998ba54b 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -298,7 +298,7 @@
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
- if (iter == rt_rq)
+ if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
continue;
spin_lock(&iter->rt_runtime_lock);