From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752415AbbJFOfb (ORCPT ); Tue, 6 Oct 2015 10:35:31 -0400 Received: from mga03.intel.com ([134.134.136.65]:56493 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751498AbbJFOfa (ORCPT ); Tue, 6 Oct 2015 10:35:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,644,1437462000"; d="scan'208";a="820598955" From: "Kirill A. Shutemov" To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: [PATCH] hugetlb: clear PG_reserved before setting PG_head on gigantic pages Date: Tue, 6 Oct 2015 17:35:24 +0300 Message-Id: <1444142124-21921-1-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.5.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PF_NO_COMPOUND for PG_reserved assumes we don't use PG_reserved for compound pages. And we generally don't. But during allocation of gigantic pages we set PG_head before clearing PG_reserved and __ClearPageReserved() steps on the VM_BUG_ON_PAGE(). The fix is trivial: set PG_head after PG_reserved. Signed-off-by: Kirill A. Shutemov Reported-by: Sasha Levin --- Andrew, this patch can be folded into "page-flags: define PG_reserved behavior on compound pages". --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6ecf61ffa65d..bd3f3e20313b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1258,8 +1258,8 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order) /* we rely on prep_new_huge_page to set the destructor */ set_compound_order(page, order); - __SetPageHead(page); __ClearPageReserved(page); + __SetPageHead(page); for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { /* * For gigantic hugepages allocated through bootmem at -- 2.5.3