From: Scott Wood Date: Sat, 27 Jul 2019 00:56:34 -0500 Subject: [PATCH 300/353] sched: migrate disable: Protect cpus_ptr with lock Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=88139859a77ae38bb0ca8c7822443ed42e90dac4 [ 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 Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt (VMware) --- 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 56c1aa35ed42..0f2c20111c09 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7247,9 +7247,8 @@ 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); @@ -7261,9 +7260,8 @@ 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);