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. > > --- > > 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. \- | -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
