Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752811AbbKKUoT (ORCPT ); Wed, 11 Nov 2015 15:44:19 -0500 Received: from mail-pa0-f52.google.com ([209.85.220.52]:33691 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752187AbbKKUoS (ORCPT ); Wed, 11 Nov 2015 15:44:18 -0500 Date: Wed, 11 Nov 2015 12:44:15 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Sergey Senozhatsky cc: Andrew Morton , Christoph Lameter , Pekka Enberg , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings In-Reply-To: <1447162326-30626-3-git-send-email-sergey.senozhatsky@gmail.com> Message-ID: References: <1447162326-30626-1-git-send-email-sergey.senozhatsky@gmail.com> <1447162326-30626-3-git-send-email-sergey.senozhatsky@gmail.com> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1555 Lines: 43 On Tue, 10 Nov 2015, Sergey Senozhatsky wrote: > Define 'end' and 'first' as volatile to suppress > gcc warnings: > > page-types.c:854:13: warning: variable 'end' might be > clobbered by 'longjmp' or 'vfork' [-Wclobbered] > page-types.c:858:6: warning: variable 'first' might be > clobbered by 'longjmp' or 'vfork' [-Wclobbered] > > Signed-off-by: Sergey Senozhatsky > --- > tools/vm/page-types.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c > index bcf5ec7..0651cd5 100644 > --- a/tools/vm/page-types.c > +++ b/tools/vm/page-types.c > @@ -851,11 +851,12 @@ static void walk_file(const char *name, const struct stat *st) > uint8_t vec[PAGEMAP_BATCH]; > uint64_t buf[PAGEMAP_BATCH], flags; > unsigned long nr_pages, pfn, i; > - off_t off, end = st->st_size; > + off_t off; > int fd; > ssize_t len; > void *ptr; > - int first = 1; > + volatile int first = 1; > + volatile off_t end = st->st_size; > > fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW); > This can't possibly be correct, the warnings are legitimate and the result of the sigsetjmp() in the function. You may be interested in returns_twice rather than marking random automatic variables as volatile. -- 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/