Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752394Ab2BTH5i (ORCPT ); Mon, 20 Feb 2012 02:57:38 -0500 Received: from mail-vw0-f46.google.com ([209.85.212.46]:59605 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235Ab2BTH5g convert rfc822-to-8bit (ORCPT ); Mon, 20 Feb 2012 02:57:36 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of geunsik.lim@gmail.com designates 10.52.174.212 as permitted sender) smtp.mail=geunsik.lim@gmail.com; dkim=pass header.i=geunsik.lim@gmail.com MIME-Version: 1.0 In-Reply-To: <20120217142806.07a97347.akpm@linux-foundation.org> References: <1328257256-1296-1-git-send-email-geunsik.lim@gmail.com> <20120217142806.07a97347.akpm@linux-foundation.org> Date: Mon, 20 Feb 2012 16:57:35 +0900 Message-ID: Subject: Re: [PATCH] Fix potentially derefencing uninitialized 'r'. From: Geunsik Lim To: Andrew Morton Cc: "H. Peter Anvin" , Yinghai Lu , linux-kernel , linux-mm Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2085 Lines: 58 On Sat, Feb 18, 2012 at 7:28 AM, Andrew Morton wrote: > On Fri,  3 Feb 2012 17:20:56 +0900 > Geunsik Lim wrote: > >> struct memblock_region 'r' will not be initialized potentially >> because of while statement's condition in __next_mem_pfn_range()function. >> Initialize struct memblock_region data structure by default. >> >> Signed-off-by: Geunsik Lim >> --- >>  mm/memblock.c |    2 +- >>  1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/mm/memblock.c b/mm/memblock.c >> index 77b5f22..867f5a2 100644 >> --- a/mm/memblock.c >> +++ b/mm/memblock.c >> @@ -671,7 +671,7 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid, >>                               unsigned long *out_end_pfn, int *out_nid) >>  { >>       struct memblock_type *type = &memblock.memory; >> -     struct memblock_region *r; >> +     struct memblock_region *r = &type->regions[*idx]; >> >>       while (++*idx < type->cnt) { >>               r = &type->regions[*idx]; > > The following `if' test prevents any such dereference. > > Maybe you saw a compilation warning (I didn't).  If so, > unintialized_var() is one way of suppressing it. Yepp. This patch is for solving compilation warning as you commented. > > A better way is to reorganise the code (nicely).  Often that option > isn't available. I will post patch again after reorganizing the code with better way. Thanks. > > -- ---- Best regards, Geunsik Lim, Samsung Electronics http://leemgs.fedorapeople.org ---- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at  http://vger.kernel.org/majordomo-info.html Please read the FAQ at  http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/