From: Michel Lespinasse <walken@google.com>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
Hugh Dickins <hughd@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: protect against concurrent vma expansion
Date: Wed, 19 Dec 2012 19:01:30 -0800 [thread overview]
Message-ID: <CANN689FoSGMUi0mC6dzXe5tXo-BL_4eFZ1NF-De38x8mNhPXcg@mail.gmail.com> (raw)
In-Reply-To: <1355968594.1415.4.camel@kernel-VirtualBox>
Hi Simon,
On Wed, Dec 19, 2012 at 5:56 PM, Simon Jeons <simon.jeons@gmail.com> wrote:
> One question.
>
> I found that mainly callsite of expand_stack() is #PF, but it holds
> mmap_sem each time before call expand_stack(), how can hold a *shared*
> mmap_sem happen?
the #PF handler calls down_read(&mm->mmap_sem) before calling expand_stack.
I think I'm just confusing you with my terminology; shared lock ==
read lock == several readers might hold it at once (I'd say they share
it)
--
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
--
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next prev parent reply other threads:[~2012-12-20 3:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-01 6:56 Michel Lespinasse
2012-12-03 23:01 ` Andrew Morton
2012-12-04 0:35 ` Michel Lespinasse
2012-12-04 0:43 ` Andrew Morton
2012-12-04 14:48 ` Michel Lespinasse
2012-12-20 1:56 ` Simon Jeons
2012-12-20 3:01 ` Michel Lespinasse [this message]
2013-01-04 0:40 ` Simon Jeons
2013-01-04 0:50 ` Michel Lespinasse
2013-01-04 1:18 ` Simon Jeons
2013-01-04 2:49 ` Al Viro
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