From: Davidlohr Bueso <dave.bueso@gmail.com>
Message-ID: <1424885948.9419.2.camel@stgolabs.net>
Subject: Re: [PATCH v3 3/3] tomoyo: reduce mmap_sem hold for mm->exe_file
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: jmorris@namei.org, akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, takedakn@nttdata.co.jp,
        linux-security-module@vger.kernel.org,
        tomoyo-dev-en@lists.sourceforge.jp
In-Reply-To: <201502252040.IHB78651.OQFSLtFFHOOJMV@I-love.SAKURA.ne.jp>
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Date: Wed, 25 Feb 2015 09:39:08 -0800
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On Wed, 2015-02-25 at 20:40 +0900, Tetsuo Handa wrote:
> Davidlohr Bueso wrote:
> > The mm->exe_file is currently serialized with mmap_sem (shared) in order
> > to both safely (1) read the file and (2) compute the realpath by calling
> > tomoyo_realpath_from_path, making it an absolute overkill. Good users will,
> > on the other hand, make use of the more standard get_mm_exe_file(), requiring
> > only holding the mmap_sem to read the value, and relying on reference
> > 
> > Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> 
> Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> James, will you apply to linux-security.git#next ?
> I'm not using publicly accessible git tree for sending pull requests.

I'm actually trying to route these through Andrew. Because there will be
lock conversions, I'm afraid that if such patches are merged in
different order to Linus' tree, it will break bisectibility as you'd
have races.

Thanks,
Davidlohr


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