Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752775AbeAFLCp (ORCPT + 1 other); Sat, 6 Jan 2018 06:02:45 -0500 Received: from the.earth.li ([46.43.34.31]:47272 "EHLO the.earth.li" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330AbeAFLCm (ORCPT ); Sat, 6 Jan 2018 06:02:42 -0500 Date: Sat, 6 Jan 2018 11:02:27 +0000 From: Jonathan McDowell To: "Rafael J. Wysocki" Cc: Andy Shevchenko , Darren Hart , ACPI Devel Maling List , Linux Kernel Mailing List , Linux Memory Management List , Joonsoo Kim , Platform Driver , Andy Lutomirski Subject: Re: [PATCH] ACPI / WMI: Call acpi_wmi_init() later Message-ID: <20180106110227.j2jkxjpjktcy6yjr@earth.li> References: <20171208151159.urdcrzl5qpfd6jnu@earth.li> <2601877.IhOx20xkUK@aspire.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 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 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. 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. \- |