[PATCH 3/4] sched: WARN when migrating to an offline CPU

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	[PATCH 3/4] sched: WARN when migrating to an offline CPU
Date	2017-09-07 17:20 +0200
Message-ID	<un6L0-1Qb-17@gated-at.bofh.it> (permalink)
References	<un6L0-1Qb-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Migrating tasks to offline CPUs is a pretty big fail, warn about it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1173,6 +1173,10 @@ void set_task_cpu(struct task_struct *p,
 	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
 				      lockdep_is_held(&task_rq(p)->lock)));
 #endif
+	/*
+	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+	 */
+	WARN_ON_ONCE(!cpu_online(new_cpu));
 #endif
 
 	trace_sched_migrate_task(p, new_cpu);

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[PATCH 3/4] sched: WARN when migrating to an offline CPU Peter Zijlstra <peterz@infradead.org> - 2017-09-07 17:20 +0200

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