[PATCH RT 14/32] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr

Steven Rostedt
2020-01-17T17:43:01Z

From: Scott Wood <swood@redhat.com>

[ Upstream commit e5606fb7b042db634ed62b4dd733d62e050e468f ]

This function is concerned with the long-term cpu mask, not the
transitory mask the task might have while migrate disabled. Before
this patch, if a task was migrate disabled at the time
__set_cpus_allowed_ptr() was called, and the new mask happened to be
equal to the cpu that the task was running on, then the mask update
would be lost.

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 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3413b9ebef1f..d6bd8129a390 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1157,7 +1157,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
goto out;
}

- if (cpumask_equal(p->cpus_ptr, new_mask))
+ if (cpumask_equal(&p->cpus_mask, new_mask))
goto out;

dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
--
2.24.1