From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:48752 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753616AbeAHWaz (ORCPT ); Mon, 8 Jan 2018 17:30:55 -0500 Date: Mon, 8 Jan 2018 14:30:49 -0800 From: Darren Hart To: Linux Stable Cc: Rafael Wysocki , Andy Shevchenko , Jonathan McDowell , Joonsoo Kim Subject: [PATCH] platform/x86: wmi: Call acpi_wmi_init() later Message-ID: <20180108223049.GA28743@fury> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: stable-owner@vger.kernel.org List-ID: commit 98b8e4e5c17bf87c1b18ed929472051dab39878c upstream Please apply to 4.9.x and later stable kernel trees (this is as far back as 86d9f48534e8 was applied). This submission should have followed Option 1, but I failed to Cc: stable in the original commit. 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 Signed-off-by: Darren Hart (VMware) --- drivers/platform/x86/wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index 791449a..daa68ac 100644 --- a/drivers/platform/x86/wmi.c +++ b/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); -- 2.9.4 -- Darren Hart VMware Open Source Technology Center