From patchwork Tue Jun 4 16:55:36 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 248765 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id E75612C00A7 for ; Wed, 5 Jun 2013 03:02:42 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Ujud1-0000Y1-DC; Tue, 04 Jun 2013 17:02:35 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Ujucw-0000Xk-Fw for kernel-team@lists.ubuntu.com; Tue, 04 Jun 2013 17:02:30 +0000 Received: from c-67-160-231-42.hsd1.ca.comcast.net ([67.160.231.42] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UjuXt-0003FB-6J; Tue, 04 Jun 2013 16:57:17 +0000 Received: from kamal by fourier with local (Exim 4.80) (envelope-from ) id 1UjuXr-0002uG-32; Tue, 04 Jun 2013 09:57:15 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 52/75] mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer Date: Tue, 4 Jun 2013 09:55:36 -0700 Message-Id: <1370364959-9475-53-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1370364959-9475-1-git-send-email-kamal@canonical.com> References: <1370364959-9475-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Cc: Benjamin Herrenschmidt , Kamal Mostafa , Hugh Dickins , "Aneesh Kumar K.V" , Andrew Morton , Linus Torvalds X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.8.13.2 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Aneesh Kumar K.V" commit 7c3425123ddfdc5f48e7913ff59d908789712b18 upstream. We should not use set_pmd_at to update pmd_t with pgtable_t pointer. set_pmd_at is used to set pmd with huge pte entries and architectures like ppc64, clear few flags from the pte when saving a new entry. Without this change we observe bad pte errors like below on ppc64 with THP enabled. BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 pmd:c000001ec0000000 Signed-off-by: Aneesh Kumar K.V Cc: Hugh Dickins Cc: Benjamin Herrenschmidt Reviewed-by: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- mm/huge_memory.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b795dcf..9459edd 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2366,7 +2366,12 @@ static void collapse_huge_page(struct mm_struct *mm, pte_unmap(pte); spin_lock(&mm->page_table_lock); BUG_ON(!pmd_none(*pmd)); - set_pmd_at(mm, address, pmd, _pmd); + /* + * We can only use set_pmd_at when establishing + * hugepmds and never for establishing regular pmds that + * points to regular pagetables. Use pmd_populate for that + */ + pmd_populate(mm, pmd, pmd_pgtable(_pmd)); spin_unlock(&mm->page_table_lock); anon_vma_unlock_write(vma->anon_vma); goto out;