linux-kernel - Re: [PATCH] fix CONFIG_IO_STRICT_DEVMEM, do not enable by default

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Date:	Wed, 20 Jan 2016 15:53:11 -0800
From:	Kees Cook <keescook@...omium.org>
To:	Dan Williams <dan.j.williams@...el.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Russell King <linux@....linux.org.uk>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Larry Finger <Larry.Finger@...inger.net>
Subject: Re: [PATCH] fix CONFIG_IO_STRICT_DEVMEM, do not enable by default

On Wed, Jan 20, 2016 at 3:48 PM, Dan Williams <dan.j.williams@...el.com> wrote:
> On Wed, Jan 20, 2016 at 3:12 PM, Kees Cook <keescook@...omium.org> wrote:
>> On Wed, Jan 20, 2016 at 2:37 PM, Dan Williams <dan.j.williams@...el.com> wrote:
>>> Larry reports: "My PowerBook G4 Aluminum with a 32-bit PPC processor
>>> fails to boot for the 4.4-git series".  This is likely due to X still
>>> needing /dev/mem access on this platform.
>>>
>>> CONFIG_IO_STRICT_DEVMEM is not yet safe to turn on when
>>> CONFIG_STRICT_DEVMEM=y.  Remove the default so that old configurations
>>> do not change behavior.
>>>
>>> Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
>>> Reported-by: Larry Finger <Larry.Finger@...inger.net>
>>> Tested-by: Larry Finger <Larry.Finger@...inger.net>
>>> Link: http://marc.info/?l=linux-kernel&m=145332012023825&w=2
>>> Cc: Arnd Bergmann <arnd@...db.de>
>>> Cc: Ingo Molnar <mingo@...hat.com>
>>> Cc: Kees Cook <keescook@...omium.org>
>>> Cc: Russell King <linux@....linux.org.uk>
>>> Cc: Andrew Morton <akpm@...ux-foundation.org>
>>> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>>> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
>>
>> Acked-by: Kees Cook <keescook@...omium.org>
>>
>
> Thanks!
>
>> This should probably be CC: stable, yes?
>
> No, this breakage is new for the current merge window.

Ah! Okay, I misunderstood the "4.4" comment. Should that be 4.5-git?

-- 
Kees Cook
Chrome OS & Brillo Security