From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751012AbdFTBzX (ORCPT ); Mon, 19 Jun 2017 21:55:23 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:30080 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750844AbdFTBzW (ORCPT ); Mon, 19 Jun 2017 21:55:22 -0400 From: Nitin Gupta To: "David S. Miller" Cc: Nitin Gupta , "David S. Miller" , Lorenzo Stoakes , Jan Kara , Michal Hocko , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/4] sparc64: Fix gup_huge_pmd Date: Mon, 19 Jun 2017 18:53:00 -0700 Message-Id: <1497923621-96708-3-git-send-email-nitin.m.gupta@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1497923621-96708-1-git-send-email-nitin.m.gupta@oracle.com> References: <1497923621-96708-1-git-send-email-nitin.m.gupta@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 The function assumes that each PMD points to head of a huge page. This is not correct as a PMD can point to start of any 8M region with a, say 256M, hugepage. The fix ensures that it points to the correct head of any PMD huge page. Signed-off-by: Nitin Gupta --- arch/sparc/mm/gup.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index 7cfa9c5..b1c649d 100644 --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -80,6 +80,8 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, refs = 0; head = pmd_page(pmd); page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT); + if (PageTail(head)) + head = compound_head(head); do { VM_BUG_ON(compound_head(page) != head); pages[*nr] = page; -- 2.9.2