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Subject: Re: [patch] mm: tiny-shmem fix lor, mmap_sem vs i_mutex
From: Matt Mackall <mpm@selenic.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>, mingo@elte.hu, a.p.zijlstra@chello.nl,
       linux-kernel@vger.kernel.org, Hugh Dickins <hugh@veritas.com>
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Date: Wed, 17 Sep 2008 13:46:42 -0700
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On Wed, 2008-09-17 at 13:14 -0700, Andrew Morton wrote:
> On Mon, 15 Sep 2008 00:12:31 +0200
> Nick Piggin <npiggin@suse.de> wrote:
> 
> > tiny-shmem calls do_truncate in shmem_file_setup. do_truncate takes i_mutex,
> > and shmem_file_setup is called with mmap_sem held. However i_mutex nests
> > outside mmap_sem.
> > 
> > Copy the code in shmem.c to avoid this problem.
> > 
> 
> It's a bit unfortunate (as in: arse-about) that we end up creating new
> files deep within the mmap code, but I guess we won't be changing that
> in a hurry.

Hugh and I talked about merging it back into one file ala the x86 32/64
merge. I've put it on my todo list.

-- 
Mathematics is the supreme nostalgia of our time.