Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751610AbcCAGQl (ORCPT ); Tue, 1 Mar 2016 01:16:41 -0500 Received: from TYO201.gate.nec.co.jp ([210.143.35.51]:33500 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751172AbcCAGQk convert rfc822-to-8bit (ORCPT ); Tue, 1 Mar 2016 01:16:40 -0500 From: Atsushi Kumagai To: "linux-kernel@vger.kernel.org" , "kexec@lists.infradead.org" Subject: [PATCH 2/2] kexec: export OFFSET(page.compound_head) to find out compound tail page Thread-Topic: [PATCH 2/2] kexec: export OFFSET(page.compound_head) to find out compound tail page Thread-Index: AdFzf09DK22rFP50Q2On6BaoqImfUw== Date: Tue, 1 Mar 2016 06:14:38 +0000 Message-ID: <0910DD04CBD6DE4193FCF86B9C00BE9701E25FD3@BPXM01GP.gisp.nec.co.jp> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.21.220.163] Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1004 Lines: 28 PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail page's page->mapping has just a poisoned data since commit 1c290f642101e6. If makedumpfile checks page->mapping of an compound tail page to distinguish anonymous page as usual, it must fail in newer kernel. So it's necessary to export OFFSET(page.compound_head) to avoid checking compound tail pages. Signed-off-by: Atsushi Kumagai --- kernel/kexec_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 7c0b61d..4726999 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1415,6 +1415,7 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_OFFSET(page, private); VMCOREINFO_OFFSET(page, compound_dtor); VMCOREINFO_OFFSET(page, compound_order); + VMCOREINFO_OFFSET(page, compound_head); VMCOREINFO_OFFSET(pglist_data, node_zones); VMCOREINFO_OFFSET(pglist_data, nr_zones); #ifdef CONFIG_FLAT_NODE_MEM_MAP -- 2.7.2