From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752422AbdKTTkW (ORCPT ); Mon, 20 Nov 2017 14:40:22 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:32695 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751867AbdKTTkS (ORCPT ); Mon, 20 Nov 2017 14:40:18 -0500 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Joonsoo Kim , Vlastimil Babka , Michal Nazarewicz , Michal Hocko , Mel Gorman , Johannes Weiner , Andrew Morton , Mike Kravetz , stable@vger.kernel.org Subject: [PATCH 1/1] mm/cma: fix alloc_contig_range ret code/potential leak Date: Mon, 20 Nov 2017 11:39:30 -0800 Message-Id: <20171120193930.23428-2-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20171120193930.23428-1-mike.kravetz@oracle.com> References: <20171120193930.23428-1-mike.kravetz@oracle.com> X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the call __alloc_contig_migrate_range() in alloc_contig_range returns -EBUSY, processing continues so that test_pages_isolated() is called where there is a tracepoint to identify the busy pages. However, it is possible for busy pages to become available between the calls to these two routines. In this case, the range of pages may be allocated. Unfortunately, the original return code (ret == -EBUSY) is still set and returned to the caller. Therefore, the caller believes the pages were not allocated and they are leaked. Update the return code with the value from test_pages_isolated(). Fixes: 8ef5849fa8a2 ("mm/cma: always check which page caused allocation failure") Cc: Signed-off-by: Mike Kravetz --- mm/page_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 77e4d3c5c57b..3605ca82fd29 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7632,10 +7632,10 @@ int alloc_contig_range(unsigned long start, unsigned long end, } /* Make sure the range is really isolated. */ - if (test_pages_isolated(outer_start, end, false)) { + ret = test_pages_isolated(outer_start, end, false); + if (ret) { pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n", __func__, outer_start, end); - ret = -EBUSY; goto done; } -- 2.13.6