From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 725E4280282 for ; Sat, 6 Jan 2018 06:02:38 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id p8so3952474wrh.17 for ; Sat, 06 Jan 2018 03:02:38 -0800 (PST) Received: from the.earth.li (the.earth.li. [2001:41c8:10:b1f:c0ff:ee:15:900d]) by mx.google.com with ESMTPS id t3si5026532wmc.40.2018.01.06.03.02.36 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 06 Jan 2018 03:02:36 -0800 (PST) Date: Sat, 6 Jan 2018 11:02:27 +0000 From: Jonathan McDowell 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: Sender: owner-linux-mm@kvack.org List-ID: 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 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. \- | -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org