linux-kernel - Re: [tip:x86/debug] x86/EFI: Properly init-annotate BGRT code

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Message-Id: <5102463602000078000B9761@nat28.tlf.novell.com>
Date:	Fri, 25 Jan 2013 07:45:42 +0000
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"Josh Triplett" <josh@...htriplett.org>
Cc:	<mingo@...nel.org>, <tglx@...utronix.de>, <mjg@...hat.com>,
	<linux-kernel@...r.kernel.org>, <hpa@...or.com>
Subject: Re: [tip:x86/debug] x86/EFI: Properly init-annotate BGRT code

>>> On 24.01.13 at 23:28, Josh Triplett <josh@...htriplett.org> wrote:
> On Thu, Jan 24, 2013 at 12:34:21PM -0800, tip-bot for Jan Beulich wrote:
>> Commit-ID:  13f0e4d2b9e2209f13d5a4122478eb79e6136870
>> Gitweb:     
> http://git.kernel.org/tip/13f0e4d2b9e2209f13d5a4122478eb79e6136870 
>> Author:     Jan Beulich <JBeulich@...e.com>
>> AuthorDate: Fri, 23 Nov 2012 16:30:07 +0000
>> Committer:  Ingo Molnar <mingo@...nel.org>
>> CommitDate: Thu, 24 Jan 2013 17:12:18 +0100
>> 
>> x86/EFI: Properly init-annotate BGRT code
>> 
>> These items are only ever referenced from initialization code.
> 
> Not true, and this patch will break the BGRT code.  bgrt_init, which
> does indeed have an __init annotation, stores bgrt_image and
> bgrt_image_size into the .private and .size fields of a sysfs
> bin_attribute, which does *not* have an __initdata annotation, and which
> will get read whenever the user reads the corresponding sysfs attribute.

Copying init-only data into a sysfs structure is no problem at all
- that structure obviously is non-__initdata and hence can be
read at any time. It was a different thing if .private and/or .size
stored _pointers_ to one of the two variables in question.

Jan

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