From b36ee36f5d6230ea331f5999401df432180eb114 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 29 Nov 2019 17:24:55 +0100 Subject: [PATCH 313/325] sched/core: migrate_enable() must access takedown_cpu_task on !HOTPLUG_CPU Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.115-rt48.tar.xz [ Upstream commit a61d1977f692e46bad99a100f264981ba08cb4bd ] The variable takedown_cpu_task is never declared/used on !HOTPLUG_CPU except for migrate_enable(). This leads to a link error. Don't use takedown_cpu_task in !HOTPLUG_CPU. Reported-by: Dick Hollenbeck Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- kernel/cpu.c | 2 ++ kernel/sched/core.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/kernel/cpu.c b/kernel/cpu.c index 2834eed32b55..d28254597f59 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -845,7 +845,9 @@ static int take_cpu_down(void *_param) return 0; } +#ifdef CONFIG_PREEMPT_RT_BASE struct task_struct *takedown_cpu_task; +#endif static int takedown_cpu(unsigned int cpu) { diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e465381b464d..cbd76324babd 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7314,9 +7314,11 @@ void migrate_enable(void) p->migrate_disable = 0; rq->nr_pinned--; +#ifdef CONFIG_HOTPLUG_CPU if (rq->nr_pinned == 0 && unlikely(!cpu_active(cpu)) && takedown_cpu_task) wake_up_process(takedown_cpu_task); +#endif if (!p->migrate_disable_scheduled) goto out; -- 2.25.1