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Message-ID: <20180106225925.GA20169@fury>
Date: Sat, 6 Jan 2018 14:59:25 -0800
From: Darren Hart <dvhart@...radead.org>
To: Jonathan McDowell <noodles@...th.li>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux Memory Management List <linux-mm@...ck.org>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Platform Driver <platform-driver-x86@...r.kernel.org>,
Andy Lutomirski <luto@...capital.net>
Subject: Re: [PATCH] ACPI / WMI: Call acpi_wmi_init() later
On Sat, Jan 06, 2018 at 11:02:27AM +0000, Jonathan McDowell wrote:
> 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 <rjw@...ysocki.net> wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > >
> > > 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@...th.li>
> > > Reported-by: Joonsoo Kim <iamjoonsoo.kim@....com>
> > > Tested-by: Jonathan McDowell <noodles@...th.li>
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > 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.
Thanks, I'll take care of that.
--
Darren Hart
VMware Open Source Technology Center
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