linux-kernel - Re: [GIT] kbuild: kconfig changes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 8 Aug 2010 17:57:12 +0200
From:	Sam Ravnborg <sam@...nborg.org>
To:	Arve Hj?nnev?g <arve@...roid.com>
Cc:	Michal Marek <mmarek@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	JBeulich@...ell.com, aris@...hat.com, catalin.marinas@....com,
	jacmet@...site.dk, justinmattock@...il.com, lizf@...fujitsu.com,
	ulfalizer.lkml@...il.com, zippel@...ux-m68k.org,
	linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [GIT] kbuild: kconfig changes

On Fri, Aug 06, 2010 at 09:43:24PM -0700, Arve Hj?nnev?g wrote:
> On Fri, Aug 6, 2010 at 9:01 PM, Sam Ravnborg <sam@...nborg.org> wrote:
> >>
> >> This change prevents some the minimal defconfig options from working.
> >> Specifically our usb gadget drivers do not get set.
> >
> > Can you help me reproduce this?
> >
> > I have found an issue with choice values in combination with
> > tristate logic that fails. I hope this is something similar.
> >
> 
> It is probably the same problem. The gadget driver that was not set is
> not buildable as a module (it is not in the mainline kernel). If I
> select another gadget driver instead it just gets changed to build as
> a module instead.
> 
> If you create a file, arch/arm/configs/test_defconfig with the following:
> CONFIG_MODULES=y
> CONFIG_USB_GADGET=y
> CONFIG_USB_MASS_STORAGE=y
> 
> then "make test_defconfig" results in .config having:
> CONFIG_USB_MASS_STORAGE=m
> 
>  (at least if you are set up to compile for arm)

Thanks Arve.

I have it reproduced now with a simple Kconfig:

$ cat Kconfig
config M
	def_bool y
	option modules

choice
	prompt "choice list"

config A
	tristate "a"

config B
	tristate "b"

endchoice

$cat defconfig
CONFIG_M=y
CONFIG_A=y
# CONFIG_B is not set


If I do:

    $scripts/kconfig/conf --defconfig=defconfig Kconfig

with the above input the resulting .config is OK.

But If I drop the line:

    # CONFIG_B is not set

in the defconfig file then I end with CONFIG_A set to m.
And this is not as expected - I cannot see why it should matter
if we specify the value of B or not.

What we see here is that savedefconfig trigger a bug in the
other part of kconfig - a bug which was not exposed before.

The reason why your patch cured it was that we then no
longer triggered the bug (at least I guess so I did not look to close).

I will look into this as time permits. I assume the fix is simple
when I find the reason.

I fear it is in menu_finalize() and that part of kconfig I have
not yet understood.

	Sam
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/