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Date: Tue, 7 Nov 2017 14:16:58 +0300
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@amacapital.net>,
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        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
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        Ingo Molnar <mingo@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: POWER: Unexpected fault when writing to brk-allocated memory
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On Tue, Nov 07, 2017 at 09:15:21AM +0100, Florian Weimer wrote:
> MAP_FIXED is near-impossible to use correctly.  I hope you don't expect
> applications to do that.  If you want address-based opt in, it should work
> without MAP_FIXED.  Sure, in obscure cases, applications might still see
> out-of-range addresses, but I expected a full opt-out based on RLIMIT_AS
> would be sufficient for them.

Just use mmap(-1), without MAP_FIXED to get full address space.

-- 
 Kirill A. Shutemov