diff mbox series

[RT,09/25] sched: migrate disable: Protect cpus_ptr with lock

Message ID c58bd5258b0f4f0b9ee767ca91402fd392a8c8db.1582320278.git.zanussi@kernel.org
State New
Headers show
Series [RT,01/25] Fix wrong-variable use in irq_set_affinity_notifier | expand

Commit Message

Tom Zanussi Feb. 21, 2020, 9:24 p.m. UTC 
From: Scott Wood <swood@redhat.com>

v4.14.170-rt75-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------


[ 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: Tom Zanussi <zanussi@kernel.org>
---
 kernel/sched/core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4708129e8df1..189e6f08575e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6923,9 +6923,8 @@  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);
@@ -6937,9 +6936,8 @@  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);