From: Rafael J. Wysocki Date: Wed, 3 Jan 2018 11:49:29 +0000 (+0100) Subject: platform/x86: wmi: Call acpi_wmi_init() later X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~7^2~288 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success/%22http:/www.example.com/cgi/success?a=commitdiff_plain;h=64ab063b7193dd8f41f54751d9612c5b00735395;p=linux-4.9.git platform/x86: wmi: Call acpi_wmi_init() later commit 98b8e4e5c17bf87c1b18ed929472051dab39878c upstream. 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) Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index ceeb8c188ef3..00d82e8443bd 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -848,5 +848,5 @@ static void __exit acpi_wmi_exit(void) pr_info("Mapper unloaded\n"); } -subsys_initcall(acpi_wmi_init); +subsys_initcall_sync(acpi_wmi_init); module_exit(acpi_wmi_exit);