From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx145.postini.com [74.125.245.145]) by kanga.kvack.org (Postfix) with SMTP id 6D8036B0044 for ; Thu, 29 Mar 2012 08:25:45 -0400 (EDT) Date: Thu, 29 Mar 2012 14:25:42 +0200 From: Michal Hocko Subject: Re: [PATCH, v2] Fix potentially derefencing uninitialized 'r'. Message-ID: <20120329122450.GA30566@tiehlicka.suse.cz> References: <1329814703-14398-1-git-send-email-geunsik.lim@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1329814703-14398-1-git-send-email-geunsik.lim@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Geunsik Lim Cc: Andrew Morton , "H. Peter Anvin" , Yinghai Lu , linux-kernel , linux-mm On Tue 21-02-12 17:58:23, Geunsik Lim wrote: > From: Geunsik Lim The warning seems to be bogus. The only caller is for_each_mem_pfn_range and even if we had type->cnt == 0 we would return before accessing r. I guess it would be more reasonable to silent the warning by __maybe_unused. > > v2: reorganize the code with better way to avoid compilation warning > via the comment of Andrew Morton. > > v1: struct memblock_region 'r' will not be initialized potentially > because of while() condition in __next_mem_pfn_range()function. > Solve the compilation warning related problem by initializing > r data structure. > > Signed-off-by: Geunsik Lim > --- > mm/memblock.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 77b5f22..b8c40c5 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -673,14 +673,18 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid, > struct memblock_type *type = &memblock.memory; > struct memblock_region *r; > > - while (++*idx < type->cnt) { > + do { > r = &type->regions[*idx]; > > + if (++*idx < type->cnt) { > if (PFN_UP(r->base) >= PFN_DOWN(r->base + r->size)) > continue; > if (nid == MAX_NUMNODES || nid == r->nid) > break; > - } > + } else > + break; > + } while (1); > + > if (*idx >= type->cnt) { > *idx = -1; > return; > -- > 1.7.8.1 > > -- > 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/ -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org