summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2021-08-26 15:37:38 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-08-26 19:02:00 +0200
commite681dcbaa4b284454fecd09617f8b24231448446 (patch)
tree9274cf04df39c1ef533537a713df7f57c92fef2f
parentsched: Fix Core-wide rq->lock for uninitialized CPUs (diff)
downloadlinux-e681dcbaa4b284454fecd09617f8b24231448446.tar.xz
linux-e681dcbaa4b284454fecd09617f8b24231448446.zip
sched: Fix get_push_task() vs migrate_disable()
push_rt_task() attempts to move the currently running task away if the next runnable task has migration disabled and therefore is pinned on the current CPU. The current task is retrieved via get_push_task() which only checks for nr_cpus_allowed == 1, but does not check whether the task has migration disabled and therefore cannot be moved either. The consequence is a pointless invocation of the migration thread which correctly observes that the task cannot be moved. Return NULL if the task has migration disabled and cannot be moved to another CPU. Fixes: a7c81556ec4d3 ("sched: Fix migrate_disable() vs rt/dl balancing") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210826133738.yiotqbtdaxzjsnfj@linutronix.de
-rw-r--r--kernel/sched/sched.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index da4295f5ab77..ddefb0419d7a 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2255,6 +2255,9 @@ static inline struct task_struct *get_push_task(struct rq *rq)
if (p->nr_cpus_allowed == 1)
return NULL;
+ if (p->migration_disabled)
+ return NULL;
+
rq->push_busy = true;
return get_task_struct(p);
}