From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754411AbXLFUmP (ORCPT ); Thu, 6 Dec 2007 15:42:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752129AbXLFUmA (ORCPT ); Thu, 6 Dec 2007 15:42:00 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.144]:54327 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752054AbXLFUl7 (ORCPT ); Thu, 6 Dec 2007 15:41:59 -0500 From: Adam Litke Subject: [PATCH] hugetlb: handle write-protection faults in follow_hugetlb_page Date: Thu, 06 Dec 2007 12:41:52 -0800 To: Andrew Morton Cc: Adam Litke , Dave Kleikamp , Ken Chen , linux-kernel@vger.kernel.org Message-Id: <20071206204152.16103.44490.stgit@kernel> Content-Type: text/plain; charset=utf-8; format=fixed Content-Transfer-Encoding: 8bit User-Agent: StGIT/0.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The follow_hugetlb_page() fix I posted (merged as git commit 5b23dbe8173c212d6a326e35347b038705603d39) missed one case. If the pte is present, but not writable and write access is requested by the caller to get_user_pages(), the code will do the wrong thing. Rather than calling hugetlb_fault to make the pte writable, it notes the presence of the pte and continues. This simple one-liner makes sure we also fault on the pte for this case. Please apply. Signed-off-by: Adam Litke Acked-by: Dave Kleikamp --- mm/hugetlb.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6121b57..6f97821 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -907,7 +907,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, */ pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); - if (!pte || pte_none(*pte)) { + if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) { int ret; spin_unlock(&mm->page_table_lock);