Re: [PATCH] ACPI / WMI: Call acpi_wmi_init() later

[Darren Hart]

On Sat, Jan 06, 2018 at 12:30:23AM +0100, Rafael J. Wysocki wrote:
> On Wed, Jan 3, 2018 at 12:49 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Calling acpi_wmi_init() at the subsys_initcall() level causes ordering
> > issues to appear on some systems and they are difficult to reproduce,
> > because there is no guaranteed ordering between subsys_initcall()
> > calls, so they may occur in different orders on different systems.
> >
> > In particular, commit 86d9f48534e8 (mm/slab: fix kmemcg cache
> > creation delayed issue) exposed one of these issues where genl_init()
> > and acpi_wmi_init() are both called at the same initcall level, but
> > the former must run before the latter so as to avoid a NULL pointer
> > dereference.
> >
> > For this reason, move the acpi_wmi_init() invocation to the
> > initcall_sync level which should still be early enough for things
> > to work correctly in the WMI land.
> >
> > Link: https://marc.info/?t=151274596700002&r=1&w=2
> > Reported-by: Jonathan McDowell <noodles@xxxxxxxx>
> > Reported-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> > Tested-by: Jonathan McDowell <noodles@xxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> 
> Guys, this fixes a crash on boot.
> 
> If there are no concerns/objections I will just take it through the ACPI tree.

Queued up and running through tests now. I'll have it in for-next as soon as
those complete assuming to issues.

-- 
Darren Hart
VMware Open Source Technology Center