From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755949Ab2IBJE4 (ORCPT ); Sun, 2 Sep 2012 05:04:56 -0400 Received: from mailout-de.gmx.net ([213.165.64.22]:53722 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755903Ab2IBJEy (ORCPT ); Sun, 2 Sep 2012 05:04:54 -0400 X-Authenticated: #5108953 X-Provags-ID: V01U2FsdGVkX19AFbEuo9FA6TbkZBwbkuv9UyFWh6yKtY1Hx2AVWq RbMvSA8JV0Dhdm Message-ID: <50432132.90307@gmx.de> Date: Sun, 02 Sep 2012 11:04:50 +0200 From: =?UTF-8?B?VG9yYWxmIEbDtnJzdGVy?= User-Agent: Mozilla/5.0 (X11; Linux i686; rv:14.0) Gecko/20120721 Thunderbird/14.0 MIME-Version: 1.0 To: Steven Rostedt , Frederic Weisbecker , Ingo Molnar CC: Linux Kernel Subject: does gcc gives a false warning in kernel/trace/trace_events_filter.c ? X-Enigmail-Version: 1.5a1pre Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current git tree of linux gave with gcc-4.6.3 : kernel/trace/trace_events_filter.c: In function ‘ftrace_function_set_filter_cb’: kernel/trace/trace_events_filter.c:2074:8: warning: ‘ret’ may be used uninitialized in this function [-Wuninitialized] which refers to this piece of code: 2061 static int ftrace_function_set_filter_cb(enum move_type move, 2062 struct filter_pred *pred, 2063 int *err, void *data) 2064 { 2065 /* Checking the node is valid for function trace. */ 2066 if ((move != MOVE_DOWN) || 2067 (pred->left != FILTER_PRED_INVALID)) { 2068 *err = ftrace_function_check_pred(pred, 0); 2069 } else { 2070 *err = ftrace_function_check_pred(pred, 1); 2071 if (*err) 2072 return WALK_PRED_ABORT; 2073 2074 *err = __ftrace_function_set_filter(pred->op == OP_EQ, 2075 pred->regex.pattern, 2076 pred->regex.len, 2077 data); 2078 } 2079 2080 return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT; 2081 } 2082 >>From a Gentoo forum user I got a hint : "Maybe it's some kind of a weird inlining issue? I think it's referring to the ret in __ftrace_function_set_filter(), which would be uninitialized if the for-loop does not run (re_cnt ≤ 0)" Now I'm wondering if re_cnt can become zero or if gcc is wrong here ? -- MfG/Sincerely Toralf Förster pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3