Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753242AbeAEXa0 (ORCPT + 1 other); Fri, 5 Jan 2018 18:30:26 -0500 Received: from mail-oi0-f66.google.com ([209.85.218.66]:35347 "EHLO mail-oi0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752370AbeAEXaY (ORCPT ); Fri, 5 Jan 2018 18:30:24 -0500 X-Google-Smtp-Source: ACJfBotwR9DSOrkpJ/BjLq1PsXH2NAPAKZZQsbF/JsgBSgSTF7vBQonZiDyEhdwnYLkUfGDBi2sidN9uWi6FfiH1rhI= MIME-Version: 1.0 In-Reply-To: <2601877.IhOx20xkUK@aspire.rjw.lan> References: <20171208151159.urdcrzl5qpfd6jnu@earth.li> <2601877.IhOx20xkUK@aspire.rjw.lan> From: "Rafael J. Wysocki" Date: Sat, 6 Jan 2018 00:30:23 +0100 X-Google-Sender-Auth: VrSoWuEw4U6p2qSjrR2OZRmnPcE Message-ID: Subject: Re: [PATCH] ACPI / WMI: Call acpi_wmi_init() later To: Andy Shevchenko , Darren Hart Cc: Jonathan McDowell , ACPI Devel Maling List , Linux Kernel Mailing List , Linux Memory Management List , Joonsoo Kim , Platform Driver , Andy Lutomirski Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, Jan 3, 2018 at 12:49 PM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > 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 > Reported-by: Joonsoo Kim > Tested-by: Jonathan McDowell > Signed-off-by: Rafael J. Wysocki 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); > > --