43 lines
1.7 KiB
Diff
43 lines
1.7 KiB
Diff
From f8b5196327b0e22ac852740408737cb40515c72c Mon Sep 17 00:00:00 2001
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Message-Id: <f8b5196327b0e22ac852740408737cb40515c72c.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Mike Galbraith <efault@gmx.de>
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Date: Sun, 19 Aug 2018 08:28:35 +0200
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Subject: [PATCH 229/333] sched: Allow pinned user tasks to be awakened to the
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CPU they pinned
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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Since commit 7af443ee16976 ("sched/core: Require cpu_active() in
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select_task_rq(), for user tasks") select_fallback_rq() will BUG() if
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the CPU to which a task has pinned itself and pinned becomes
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!cpu_active() while it slept.
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The task will continue running on the to-be-removed CPU and will remove
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itself from the CPU during takedown_cpu() (while cpuhp_pin_lock will be
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acquired) and move to another CPU based on its mask after the
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migrate_disable() section has been left.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Mike Galbraith <efault@gmx.de>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/sched/core.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/kernel/sched/core.c b/kernel/sched/core.c
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index f13cc0073bbc..297934719db9 100644
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--- a/kernel/sched/core.c
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+++ b/kernel/sched/core.c
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@@ -904,7 +904,7 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
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if (!cpumask_test_cpu(cpu, p->cpus_ptr))
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return false;
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- if (is_per_cpu_kthread(p))
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+ if (is_per_cpu_kthread(p) || __migrate_disabled(p))
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return cpu_online(cpu);
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return cpu_active(cpu);
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--
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2.17.1
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