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> --- 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); -- 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>
