Re: [PATCH] arm64: Call numa_store_cpu_info() earlier.

From: Catalin Marinas
Date: Thu Sep 22 2016 - 13:07:02 EST

On Tue, Sep 20, 2016 at 11:46:35AM -0700, David Daney wrote:
> From: David Daney <david.daney@xxxxxxxxxx>
> The wq_numa_init() function makes a private CPU to node map by calling
> cpu_to_node() early in the boot process, before the non-boot CPUs are
> brought online. Since the default implementation of cpu_to_node()
> returns zero for CPUs that have never been brought online, the
> workqueue system's view is that *all* CPUs are on node zero.
> When the unbound workqueue for a non-zero node is created, the
> tsk_cpus_allowed() for the worker threads is the empty set because
> there are, in the view of the workqueue system, no CPUs on non-zero
> nodes. The code in try_to_wake_up() using this empty cpumask ends up
> using the cpumask empty set value of NR_CPUS as an index into the
> per-CPU area pointer array, and gets garbage as it is one past the end
> of the array. This results in:

Queued for 4.8. Thanks.