From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id 09AB16B0253 for ; Mon, 6 Nov 2017 03:10:16 -0500 (EST) Received: by mail-oi0-f71.google.com with SMTP id s185so9474804oif.16 for ; Mon, 06 Nov 2017 00:10:16 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id a2si1356261otd.64.2017.11.06.00.10.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Nov 2017 00:10:15 -0800 (PST) Subject: Re: POWER: Unexpected fault when writing to brk-allocated memory References: <20171105231850.5e313e46@roar.ozlabs.ibm.com> <871slcszfl.fsf@linux.vnet.ibm.com> From: Florian Weimer Message-ID: Date: Mon, 6 Nov 2017 09:10:10 +0100 MIME-Version: 1.0 In-Reply-To: <871slcszfl.fsf@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Aneesh Kumar K.V" , Nicholas Piggin , "Kirill A. Shutemov" Cc: linuxppc-dev@lists.ozlabs.org, linux-mm On 11/06/2017 07:18 AM, Aneesh Kumar K.V wrote: > We should not return that address, unless we requested with a hint value > of > 128TB. IIRC we discussed this early during the mmap interface > change and said, we will return an address > 128T only if the hint > address is above 128TB (not hint addr + length). I am not sure why > we are finding us returning and address > 128TB with paca limit set to > 128TB? See the memory maps I posted. I think it was not anticipated that the heap could be near the 128 TiB limit because it is placed next to the initially mapped object. I think this could become worse once we have static PIE support because static PIE binaries likely have the same memory layout. (Ordinary PIE does not.) Thanks, Florian -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org