Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757183AbdIHUnJ (ORCPT ); Fri, 8 Sep 2017 16:43:09 -0400 Received: from mail-qt0-f196.google.com ([209.85.216.196]:35604 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757080AbdIHUnG (ORCPT ); Fri, 8 Sep 2017 16:43:06 -0400 X-Google-Smtp-Source: AOwi7QBGIMZZGWF/ooeHzug03tw8erAoDkOP9HJObXHuto3NlxvLRGEv27P5riql0xo4Cs3KmGZS2Q== Subject: [PATCH] mm/memory_hotplug: fix wrong casting for __remove_section() To: linux-mm@kvack.org Cc: Michal Hocko , LKML , qiuxishi@huawei.com, arbab@linux.vnet.ibm.com, Vlastimil Babka , Reza Arbab From: YASUAKI ISHIMATSU Message-ID: <51a59ec3-e7ba-2562-1917-036b8181092c@gmail.com> Date: Fri, 8 Sep 2017 16:43:04 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2248 Lines: 59 __remove_section() calls __remove_zone() to shrink zone and pgdat. But due to wrong castings, __remvoe_zone() cannot shrink zone and pgdat correctly if pfn is over 0xffffffff. So the patch fixes the following 3 wrong castings. 1. find_smallest_section_pfn() returns 0 or start_pfn which defined as unsigned long. But the function always returns 32bit value since the function is defined as int. 2. find_biggest_section_pfn() returns 0 or pfn which defined as unsigned long. the function always returns 32bit value since the function is defined as int. 3. __remove_section() calculates start_pfn using section_nr_to_pfn() and scn_nr. section_nr_to_pfn() just shifts scn_nr by PFN_SECTION_SHIFT bit. But since scn_nr is defined as int, section_nr_to_pfn() always return 32 bit value. The patch fixes the wrong castings. Signed-off-by: Yasuaki Ishimatsu --- mm/memory_hotplug.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 73bf17d..3514ef2 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -331,7 +331,7 @@ int __ref __add_pages(int nid, unsigned long phys_start_pfn, #ifdef CONFIG_MEMORY_HOTREMOVE /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ -static int find_smallest_section_pfn(int nid, struct zone *zone, +static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { @@ -356,7 +356,7 @@ static int find_smallest_section_pfn(int nid, struct zone *zone, } /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ -static int find_biggest_section_pfn(int nid, struct zone *zone, +static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { @@ -544,7 +544,7 @@ static int __remove_section(struct zone *zone, struct mem_section *ms, return ret; scn_nr = __section_nr(ms); - start_pfn = section_nr_to_pfn(scn_nr); + start_pfn = section_nr_to_pfn((unsigned long)scn_nr); __remove_zone(zone, start_pfn); sparse_remove_one_section(zone, ms, map_offset); -- 1.8.3.1