From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932162AbVIXKbO (ORCPT ); Sat, 24 Sep 2005 06:31:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932163AbVIXKbO (ORCPT ); Sat, 24 Sep 2005 06:31:14 -0400 Received: from silver.veritas.com ([143.127.12.111]:94 "EHLO silver.veritas.com") by vger.kernel.org with ESMTP id S932162AbVIXKbN (ORCPT ); Sat, 24 Sep 2005 06:31:13 -0400 Date: Sat, 24 Sep 2005 11:30:43 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: Andrew Morton cc: Nick Piggin , linux-kernel@vger.kernel.org Subject: [PATCH] mremap move ZERO_PAGE fix Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-OriginalArrivalTime: 24 Sep 2005 10:31:09.0041 (UTC) FILETIME=[13B91610:01C5C0F3] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Fix nasty little bug we've missed in Nick's mremap move ZERO_PAGE patch. The "pte" at that point may be a swap entry or a pte_file entry: we must check pte_present before perhaps corrupting such an entry. Patch below against 2.6.14-rc2-mm1, but the same bug is in 2.6.14-rc2's mm/mremap.c, and more dangerous there since it's affecting all arches: I think the safest course is to send Nick's patch and Yoichi's build fix and this fix (build tested) on to Linus - so only MIPS can be affected. Signed-off-by: Hugh Dickins --- 2.6.14-rc2-mm1/include/asm-generic/pgtable.h 2005-09-22 12:32:00.000000000 +0100 +++ linux/include/asm-generic/pgtable.h 2005-09-24 10:51:41.000000000 +0100 @@ -164,7 +164,8 @@ static inline void ptep_set_wrprotect(st #define move_pte(pte, prot, old_addr, new_addr) \ ({ \ pte_t newpte = (pte); \ - if (pfn_valid(pte_pfn(pte)) && pte_page(pte) == ZERO_PAGE(old_addr)) \ + if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \ + pte_page(pte) == ZERO_PAGE(old_addr)) \ newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \ newpte; \ })