From 457be908c83637ee10bda085a23dc05afa3b14a0 Mon Sep 17 00:00:00 2001 From: Vincent Guittot Date: Thu, 26 Apr 2018 12:19:32 +0200 Subject: [PATCH] sched/fair: Fix the update of blocked load when newly idle With commit: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") ... we release the rq->lock when updating blocked load of idle CPUs. This opens a time window during which another CPU can add a task to this CPU's cfs_rq. The check for newly added task of idle_balance() is not in the common path. Move the out label to include this check. Reported-by: Heiner Kallweit Tested-by: Geert Uytterhoeven Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 31e77c93e432 ("sched/fair: Update blocked load when newly idle") Link: http://lkml.kernel.org/r/20180426103133.GA6953@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 54dc31e7ab9b..e3002e5ada31 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9847,6 +9847,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) if (curr_cost > this_rq->max_idle_balance_cost) this_rq->max_idle_balance_cost = curr_cost; +out: /* * While browsing the domains, we released the rq lock, a task could * have been enqueued in the meantime. Since we're not going idle, @@ -9855,7 +9856,6 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) if (this_rq->cfs.h_nr_running && !pulled_task) pulled_task = 1; -out: /* Move the next balance forward */ if (time_after(this_rq->next_balance, next_balance)) this_rq->next_balance = next_balance; -- 2.30.2