From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86/refcount: Implement fast refcount_t handling
Date: Mon, 24 Apr 2017 12:48:53 +0200
Message-ID: <20170424104853.k6s2jjmcdbbghit4@hirez.programming.kicks-ass.net>
References: <20170421220939.GA65363@beast>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Return-path: <kernel-hardening-return-7508-glkh-kernel-hardening=m.gmane.org@lists.openwall.com>
List-Post: <mailto:kernel-hardening@lists.openwall.com>
List-Help: <mailto:kernel-hardening-help@lists.openwall.com>
List-Unsubscribe: <mailto:kernel-hardening-unsubscribe@lists.openwall.com>
List-Subscribe: <mailto:kernel-hardening-subscribe@lists.openwall.com>
Content-Disposition: inline
In-Reply-To: <20170421220939.GA65363@beast>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, Eric Biggers <ebiggers3@gmail.com>, Christoph Hellwig <hch@infradead.org>, "axboe@kernel.dk" <axboe@kernel.dk>, James Bottomley <James.Bottomley@hansenpartnership.com>, Elena Reshetova <elena.reshetova@intel.com>, Hans Liljestrand <ishkamiel@gmail.com>, David Windsor <dwindsor@gmail.com>, x86@kernel.org, Ingo Molnar <mingo@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jann Horn <jann@thejh.net>, davem@davemloft.net, linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, PaX Team <pageexec@freemail.hu>
List-Id: linux-arch.vger.kernel.org

On Fri, Apr 21, 2017 at 03:09:39PM -0700, Kees Cook wrote:
> diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
> index e3f4cd8876b5..1bdafb29b802 100644
> --- a/drivers/misc/lkdtm_bugs.c
> +++ b/drivers/misc/lkdtm_bugs.c
> @@ -135,9 +135,15 @@ void lkdtm_HUNG_TASK(void)
>  	schedule();
>  }
>  
> +#ifdef CONFIG_FAST_REFCOUNT
> +#define REFCOUNT_MAX	INT_MAX
> +#else
> +#define REFCOUNT_MAX	UINT_MAX
> +#endif

That doesn't seem like a sensible place for this.

From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-arch-owner@vger.kernel.org>
Received: from merlin.infradead.org ([205.233.59.134]:50788 "EHLO
        merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1168702AbdDXKtC (ORCPT
        <rfc822;linux-arch@vger.kernel.org>); Mon, 24 Apr 2017 06:49:02 -0400
Date: Mon, 24 Apr 2017 12:48:53 +0200
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86/refcount: Implement fast refcount_t handling
Message-ID: <20170424104853.k6s2jjmcdbbghit4@hirez.programming.kicks-ass.net>
References: <20170421220939.GA65363@beast>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20170421220939.GA65363@beast>
Sender: linux-arch-owner@vger.kernel.org
List-ID: <linux-arch.vger.kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, Eric Biggers <ebiggers3@gmail.com>, Christoph Hellwig <hch@infradead.org>, "axboe@kernel.dk" <axboe@kernel.dk>, James Bottomley <James.Bottomley@hansenpartnership.com>, Elena Reshetova <elena.reshetova@intel.com>, Hans Liljestrand <ishkamiel@gmail.com>, David Windsor <dwindsor@gmail.com>, x86@kernel.org, Ingo Molnar <mingo@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jann Horn <jann@thejh.net>, davem@davemloft.net, linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, PaX Team <pageexec@freemail.hu>
Message-ID: <20170424104853.tgpVB3WPG0ZR2us9jOjX45F9C8aDluukXQ2GLjx7yaA@z>

On Fri, Apr 21, 2017 at 03:09:39PM -0700, Kees Cook wrote:
> diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
> index e3f4cd8876b5..1bdafb29b802 100644
> --- a/drivers/misc/lkdtm_bugs.c
> +++ b/drivers/misc/lkdtm_bugs.c
> @@ -135,9 +135,15 @@ void lkdtm_HUNG_TASK(void)
>  	schedule();
>  }
>  
> +#ifdef CONFIG_FAST_REFCOUNT
> +#define REFCOUNT_MAX	INT_MAX
> +#else
> +#define REFCOUNT_MAX	UINT_MAX
> +#endif

That doesn't seem like a sensible place for this.