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From: Christian Dietrich <stettberger@dokucode.de>
To: Tejun Heo <tj@kernel.org>, David Howells <dhowells@redhat.com>,
	Christoph Lameter <cl@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Dead Config in mm/percpu.c
Date: Wed, 21 Jul 2010 11:22:51 +0200	[thread overview]
Message-ID: <861vaxjij8.fsf@peer.zerties.org> (raw)

Hi all!
       
        As part of the VAMOS[0] research project at the University of
Erlangen we are looking at multiple integrity errors in linux'
configuration system.

        I've been running a check on the mm/ sourcetree for
config Items not defined in Kconfig and found 1 such case. Sourcecode
blocks depending on these Items are not reachable from a vanilla
kernel -- dead code. I've seen such dead blocks made on purpose
e.g. while integrating new features into the kernel but generally
they're just useless.

We found, that CONFIG_NEED_PER_CPU_KM is a dead symbol, so it isn't defined
anywhere. Cause of that the percpu_km.c is never included anywhere. Is
this a intended dead symbol, for use in out of tree development, or is
this just an error?

Regards
        Christian Dietrich
-- 
(λ x . x x) (λ x . x x) -- See how beatiful the lambda is
No documentation is better than bad documentation
-- Das Ausdrucken dieser Mail wird urheberrechtlich verfolgt.

WARNING: multiple messages have this Message-ID (diff)
From: Christian Dietrich <stettberger@dokucode.de>
To: Tejun Heo <tj@kernel.org>, David Howells <dhowells@redhat.com>,
	Christoph Lameter <cl@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Dead Config in mm/percpu.c
Date: Wed, 21 Jul 2010 11:22:51 +0200	[thread overview]
Message-ID: <861vaxjij8.fsf@peer.zerties.org> (raw)

Hi all!
       
        As part of the VAMOS[0] research project at the University of
Erlangen we are looking at multiple integrity errors in linux'
configuration system.

        I've been running a check on the mm/ sourcetree for
config Items not defined in Kconfig and found 1 such case. Sourcecode
blocks depending on these Items are not reachable from a vanilla
kernel -- dead code. I've seen such dead blocks made on purpose
e.g. while integrating new features into the kernel but generally
they're just useless.

We found, that CONFIG_NEED_PER_CPU_KM is a dead symbol, so it isn't defined
anywhere. Cause of that the percpu_km.c is never included anywhere. Is
this a intended dead symbol, for use in out of tree development, or is
this just an error?

Regards
        Christian Dietrich
-- 
(λ x . x x) (λ x . x x) -- See how beatiful the lambda is
No documentation is better than bad documentation
-- Das Ausdrucken dieser Mail wird urheberrechtlich verfolgt.

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             reply	other threads:[~2010-07-21  9:23 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-21  9:22 Christian Dietrich [this message]
2010-07-21  9:22 ` Dead Config in mm/percpu.c Christian Dietrich
2010-07-21 15:12 ` Tejun Heo
2010-07-21 15:12   ` Tejun Heo
2010-08-10  6:26   ` Mike Frysinger
2010-08-10  6:26     ` Mike Frysinger

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