From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/2763 Path: news.gmane.org!not-for-mail From: Jens Gustedt Newsgroups: gmane.linux.lib.musl.general Subject: [PATCH 1/3] protect some clobbered variables with volatile Date: Sun, 10 Feb 2013 23:31:41 +0100 Message-ID: <1360535421.23424.467.camel@eris.loria.fr> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1360535512 5296 80.91.229.3 (10 Feb 2013 22:31:52 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 10 Feb 2013 22:31:52 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-2764-gllmg-musl=m.gmane.org@lists.openwall.com Sun Feb 10 23:32:14 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1U4fRV-000885-BD for gllmg-musl@plane.gmane.org; Sun, 10 Feb 2013 23:32:13 +0100 Original-Received: (qmail 3861 invoked by uid 550); 10 Feb 2013 22:31:54 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 3853 invoked from network); 10 Feb 2013 22:31:54 -0000 X-IronPort-AV: E=Sophos;i="4.84,639,1355094000"; d="scan'208";a="2216030" Resent-From: Jens Gustedt Resent-To: musl@lists.openwall.com Resent-Cc: musl X-Mailer: Evolution 3.2.3-0ubuntu6 Xref: news.gmane.org gmane.linux.lib.musl.general:2763 Archived-At: When switching optimization to higher levels (-O3) and enable link time optimization (-flto) gcc finds two variables that might be clobbered accross longjmp (orig_tail in dynlink) or vfork (f in popen): src/ldso/dynlink.c:1014:27: warning: variable ‘orig_tail’ might be clobbered by ‘longjmp’ or ‘vfork’ [-Wclobbered] src/stdio/popen.c:21:8: warning: variable ‘f’ might be clobbered by ‘longjmp’ or ‘vfork’ [-Wclobbered] Trust the analysis of the compiler and protect these variables with volatile. Both variables are only loaded once or twice, so this should never cause a performance penalty. 1 1 src/ldso/dynlink.c 1 1 src/stdio/popen.c diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c index efbec8f..e19a21f 100644 --- a/src/ldso/dynlink.c +++ b/src/ldso/dynlink.c @@ -1011,7 +1011,7 @@ void __init_ldso_ctors(void) void *dlopen(const char *file, int mode) { - struct dso *volatile p, *orig_tail, *next; + struct dso *volatile p, *volatile orig_tail, *next; size_t orig_tls_cnt, orig_tls_offset, orig_tls_align; size_t i; int cs; diff --git a/src/stdio/popen.c b/src/stdio/popen.c index ed20f5a..e5fbc4f 100644 --- a/src/stdio/popen.c +++ b/src/stdio/popen.c @@ -18,7 +18,7 @@ FILE *popen(const char *cmd, const char *mode) { int p[2], op, i; pid_t pid; - FILE *f; + FILE *volatile f; sigset_t old; const char *modes = "rw", *mi = strchr(modes, *mode); -- 1.7.9.5