lkml.org 
[lkml]   [2018]   [Jan]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ACPI / WMI: Call acpi_wmi_init() later
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@rjwysocki.net> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > 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@earth.li>
> > Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > Tested-by: Jonathan McDowell <noodles@earth.li>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> 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.

> > ---
> > drivers/platform/x86/wmi.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > Index: linux-pm/drivers/platform/x86/wmi.c
> > ===================================================================
> > --- linux-pm.orig/drivers/platform/x86/wmi.c
> > +++ linux-pm/drivers/platform/x86/wmi.c
> > @@ -1458,5 +1458,5 @@ static void __exit acpi_wmi_exit(void)
> > class_unregister(&wmi_bus_class);
> > }
> >
> > -subsys_initcall(acpi_wmi_init);
> > +subsys_initcall_sync(acpi_wmi_init);
> > module_exit(acpi_wmi_exit);
> >
> > --

J.

--
/-\ | 101 things you can't have too much
|@/ Debian GNU/Linux Developer | of : 36 - Spare video tapes.
\- |

\
 
 \ /
  Last update: 2018-01-06 12:03    [W:0.041 / U:0.484 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site