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Date: Mon, 16 Mar 2015 20:44:46 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Hugh Dickins <hughd@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jan Kratochvil <jan.kratochvil@redhat.com>,
        Sergio Durigan Junior <sergiodj@redhat.com>,
        GDB Patches <gdb-patches@sourceware.org>,
        Pedro Alves <palves@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: install_special_mapping && vm_pgoff (Was: vvar, gup &&
	coredump)
Message-ID: <20150316194446.GA21791@redhat.com>
References: <20150305154827.GA9441@host1.jankratochvil.net> <87zj7r5fpz.fsf@redhat.com> <20150305205744.GA13165@host1.jankratochvil.net> <20150311200052.GA22654@redhat.com> <20150312143438.GA4338@redhat.com> <CALCETrW5rmAHutzm_OwK2LTd_J0XByV3pvWGyW=AmC=v7rLfhQ@mail.gmail.com> <20150312165423.GA10073@redhat.com> <20150312174653.GA13086@redhat.com> <20150316190154.GA18472@redhat.com> <CALCETrU9pLE2x3+vei1xw6B8uu4B33DOEzP03ue9DeS8sJhYUg@mail.gmail.com>
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On 03/16, Andy Lutomirski wrote:
>
> Ick, you're probably right.  For what it's worth, the vdso *seems* to
> be okay (on 64-bit only, and only if you don't poke at it too hard) if
> you mremap it in one piece.  CRIU does that.

I need to run away till tomorrow, but looking at this code even if "one piece"
case doesn't look right if it was cow'ed. I'll verify tomorrow.

Oleg.