From: Michel Lespinasse <walken@google.com>
To: Ric Mason <ric.masonn@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] mm: mlock: document scary-looking stack expansion mlock chain
Date: Wed, 20 Feb 2013 22:22:58 +0800 [thread overview]
Message-ID: <CANN689FizixMWu7hKMV055=SY_Sg1rmYrB_KAEwOBP1tEOZw+Q@mail.gmail.com> (raw)
In-Reply-To: <5124C6CF.1020001@gmail.com>
On Wed, Feb 20, 2013 at 8:51 PM, Ric Mason <ric.masonn@gmail.com> wrote:
> On 02/01/2013 02:10 PM, Johannes Weiner wrote:
>>
>> The fact that mlock calls get_user_pages, and get_user_pages might
>> call mlock when expanding a stack looks like a potential recursion.
>
> Why expand stack need call mlock? I can't find it in the codes, could you
> point out to me?
Its hidden in find_expand_vma(). Basically if the existing stack is
already mlocked, any additional stack expansions get mlocked as well.
--
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.
--
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next prev parent reply other threads:[~2013-02-20 14:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-01 6:10 Johannes Weiner
2013-02-20 12:51 ` Ric Mason
2013-02-20 14:22 ` Michel Lespinasse [this message]
2013-02-20 14:24 ` Michel Lespinasse
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