From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vGsQm6zwpzDqDv for ; Mon, 6 Feb 2017 13:50:24 +1100 (AEDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v162mYCB041668 for ; Sun, 5 Feb 2017 21:50:21 -0500 Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) by mx0a-001b2d01.pphosted.com with ESMTP id 28dbu3rhaj-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Sun, 05 Feb 2017 21:50:21 -0500 Received: from localhost by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 5 Feb 2017 21:50:20 -0500 Subject: Re: [PATCH] powerpc/mm: fix a hardcode on memory boundary checking To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20170112090906.17864-1-rui.teng@linux.vnet.ibm.com> <877f5bvbjm.fsf@concordia.ellerman.id.au> Cc: "Aneesh Kumar K.V" , Boqun Feng , jia he From: Rui Teng Date: Mon, 6 Feb 2017 10:50:21 +0800 MIME-Version: 1.0 In-Reply-To: <877f5bvbjm.fsf@concordia.ellerman.id.au> Content-Type: text/plain; charset=windows-1252; format=flowed Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 31/01/2017 5:11 PM, Michael Ellerman wrote: > Rui Teng writes: > >> The offset of hugepage block will not be 16G, if the expected >> page is more than one. Calculate the totol size instead of the >> hardcode value. > > I assume you found this by code inspection and not by triggering an > actual bug? Yes, I found this problem only by code inspection. We were finding the ways to enable 16G huge page besides changing the device tree. For example, provide a new interface to set these size and pages parameters. So that I think it may cause problem here. > > cheers > >> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c >> index 8033493..b829f8e 100644 >> --- a/arch/powerpc/mm/hash_utils_64.c >> +++ b/arch/powerpc/mm/hash_utils_64.c >> @@ -506,7 +506,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node, >> printk(KERN_INFO "Huge page(16GB) memory: " >> "addr = 0x%lX size = 0x%lX pages = %d\n", >> phys_addr, block_size, expected_pages); >> - if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) { >> + if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) { >> memblock_reserve(phys_addr, block_size * expected_pages); >> add_gpage(phys_addr, block_size, expected_pages); >> } >> -- >> 2.9.0 >