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

[Darren Hart]

On Sat, Jan 06, 2018 at 11:02:27AM +0000, Jonathan McDowell wrote:
> 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.
> 
> Note that I first started seeing it in v4.9 so would ideally hit the
> appropriate stable trees too.

Thanks, I'll take care of that.

-- 
Darren Hart
VMware Open Source Technology Center