[RFC 2/3] rt: Update nr_cpus_allowed if the affinity of a task changes while its migration is disabled

[Daniel Bristot de Oliveira]

Currently, if the affinity of a task changes when it is with migration
disabled, the nr_cpus_allowed is not being updated, creating an
inconsistency between nr_cpus_allowed and cpumask_weight(cpus_allowed)

This patch fixes this problem by calling set_cpus_allowed_common()
if the cpumask of a task changes while it is with migration disable.

Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Luis Claudio R. Goncalves <lgoncalv@xxxxxxxxxx>
Cc: Clark Williams <williams@xxxxxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: LKML <linux-kernel@xxxxxxxxxxxxxxx>
Cc: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index aeb3e12..0396bf2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1146,7 +1146,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
 	lockdep_assert_held(&p->pi_lock);
 
 	if (__migrate_disabled(p)) {
-		cpumask_copy(&p->cpus_allowed, new_mask);
+		set_cpus_allowed_common(p, new_mask);
 		return;
 	}
 
-- 
2.9.4