PATCHES/patches/platform-x86-wmi-Call-acpi_wmi_init-later.patch

From 98b8e4e5c17bf87c1b18ed929472051dab39878c Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Wed, 3 Jan 2018 12:49:29 +0100
Subject: [PATCH] platform/x86: wmi: Call acpi_wmi_init() later

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@earth.li>
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: Jonathan McDowell <noodles@earth.li>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
---
 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 791449a2370f..daa68acbc900 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1268,5 +1268,5 @@ static void __exit acpi_wmi_exit(void)
        bus_unregister(&wmi_bus_type);
 }
 
-subsys_initcall(acpi_wmi_init);
+subsys_initcall_sync(acpi_wmi_init);
 module_exit(acpi_wmi_exit);
1	From 98b8e4e5c17bf87c1b18ed929472051dab39878c Mon Sep 17 00:00:00 2001
2	From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
3	Date: Wed, 3 Jan 2018 12:49:29 +0100
4	Subject: [PATCH] platform/x86: wmi: Call acpi_wmi_init() later
5
6	Calling acpi_wmi_init() at the subsys_initcall() level causes ordering
7	issues to appear on some systems and they are difficult to reproduce,
8	because there is no guaranteed ordering between subsys_initcall()
9	calls, so they may occur in different orders on different systems.
10
11	In particular, commit 86d9f48534e8 (mm/slab: fix kmemcg cache
12	creation delayed issue) exposed one of these issues where genl_init()
13	and acpi_wmi_init() are both called at the same initcall level, but
14	the former must run before the latter so as to avoid a NULL pointer
15	dereference.
16
17	For this reason, move the acpi_wmi_init() invocation to the
18	initcall_sync level which should still be early enough for things
19	to work correctly in the WMI land.
20
21	Link: https://marc.info/?t=151274596700002&r=1&w=2
22	Reported-by: Jonathan McDowell <noodles@earth.li>
23	Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
24	Tested-by: Jonathan McDowell <noodles@earth.li>
25	Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
26	Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
27	---
28	drivers/platform/x86/wmi.c \| 2 +-
29	1 file changed, 1 insertion(+), 1 deletion(-)
30
31	diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
32	index 791449a2370f..daa68acbc900 100644
33	--- a/drivers/platform/x86/wmi.c
34	+++ b/drivers/platform/x86/wmi.c
35	@@ -1268,5 +1268,5 @@ static void __exit acpi_wmi_exit(void)
36	bus_unregister(&wmi_bus_type);
37	}
38
39	-subsys_initcall(acpi_wmi_init);
40	+subsys_initcall_sync(acpi_wmi_init);
41	module_exit(acpi_wmi_exit);