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authorPeter Zijlstra <peterz@infradead.org>2017-10-09 10:36:53 +0200
committerIngo Molnar <mingo@kernel.org>2017-10-10 10:14:03 +0200
commit024c9d2faebdad3fb43fe49ad68e91a36190f1e2 (patch)
tree85959cb1c5d5ffe471c7c917a4cf80eba44bf59d /kernel/sched
parentf2cdd9cc6c97e617b95f430f527a6e3165e1bee8 (diff)
downloadlinux-024c9d2faebdad3fb43fe49ad68e91a36190f1e2.tar.gz
sched/core: Ensure load_balance() respects the active_mask
While load_balance() masks the source CPUs against active_mask, it had
a hole against the destination CPU. Ensure the destination CPU is also
part of the 'domain-mask & active-mask' set.

Reported-by: Levin, Alexander (Sasha Levin) <alexander.levin@verizon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 77d1dfda0e79 ("sched/topology, cpuset: Avoid spurious/wrong domain rebuilds")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/fair.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ed2ab474ec93..d3f3094856fe 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8043,6 +8043,13 @@ static int should_we_balance(struct lb_env *env)
 	int cpu, balance_cpu = -1;
 
 	/*
+	 * Ensure the balancing environment is consistent; can happen
+	 * when the softirq triggers 'during' hotplug.
+	 */
+	if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
+		return 0;
+
+	/*
 	 * In the newly idle case, we will allow all the cpu's
 	 * to do the newly idle load balance.
 	 */