On 2019-07-27 00:56:32 [-0500], Scott Wood wrote:
> 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.
lost as in "would not be carried out" I assume.
> Signed-off-by: Scott Wood <swood@xxxxxxxxxx>
> ---
> 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 c3407707e367..6e643d656d71 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1218,7 +1218,7 @@ 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;
>
> if (!cpumask_intersects(new_mask, cpu_valid_mask)) {
Sebastian
