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. > --- > 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); > > --
