Re: [PATCH RT 2/8] sched: __set_cpus_allowed_ptr: Check cpus_mask, not cpus_ptr

[Scott Wood]

On Tue, 2019-09-17 at 16:57 +0200, Sebastian Andrzej Siewior wrote:
> 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.

Right.  The old mask would be restored upon migrate_enable() even though
that's no longer the policy that was requested.

-Scott