From: Scott Wood swood@redhat.com
[ Upstream commit fd844ba9ae59b51e34e77105d79f8eca780b3bd6 ]
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: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Link: https://lkml.kernel.org/r/20200617121742.cpxppyi7twxmpin7@linutronix.de Signed-off-by: Sasha Levin sashal@kernel.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 361cbc2dc9667..f5537f87c1928 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1649,7 +1649,7 @@ 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);