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From c4c6908e112c8368299d23485a921dcc83876ec2 Mon Sep 17 00:00:00 2001
From: Scott Wood <swood@redhat.com>
Date: Sat, 27 Jul 2019 00:56:34 -0500
Subject: [PATCH 301/347] sched: migrate disable: Protect cpus_ptr with lock
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
[ Upstream commit 27ee52a891ed2c7e2e2c8332ccae0de7c2674b09 ]
Various places assume that cpus_ptr is protected by rq/pi locks,
so don't change it before grabbing those locks.
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/sched/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e64d2b2b3a69..6f91ee2b7e91 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7244,9 +7244,8 @@ migrate_disable_update_cpus_allowed(struct task_struct *p)
struct rq *rq;
struct rq_flags rf;
- p->cpus_ptr = cpumask_of(smp_processor_id());
-
rq = task_rq_lock(p, &rf);
+ p->cpus_ptr = cpumask_of(smp_processor_id());
update_nr_migratory(p, -1);
p->nr_cpus_allowed = 1;
task_rq_unlock(rq, p, &rf);
@@ -7258,9 +7257,8 @@ migrate_enable_update_cpus_allowed(struct task_struct *p)
struct rq *rq;
struct rq_flags rf;
- p->cpus_ptr = &p->cpus_mask;
-
rq = task_rq_lock(p, &rf);
+ p->cpus_ptr = &p->cpus_mask;
p->nr_cpus_allowed = cpumask_weight(&p->cpus_mask);
update_nr_migratory(p, 1);
task_rq_unlock(rq, p, &rf);
--
2.36.1
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