From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18C52C10F0E for ; Tue, 9 Apr 2019 13:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2EFE20880 for ; Tue, 9 Apr 2019 13:21:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726464AbfDINVZ (ORCPT ); Tue, 9 Apr 2019 09:21:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:38860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726035AbfDINVZ (ORCPT ); Tue, 9 Apr 2019 09:21:25 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 50E112084C; Tue, 9 Apr 2019 13:21:24 +0000 (UTC) Date: Tue, 9 Apr 2019 09:21:22 -0400 From: Steven Rostedt To: Rikard Falkeborn Cc: linux-kernel@vger.kernel.org, acme@redhat.com, tstoyanov@vmware.com, Linux Trace Devel Subject: Re: [PATCH] tools lib traceevent: Fix missing equality check for strcmp Message-ID: <20190409092122.2e8f62f0@gandalf.local.home> In-Reply-To: <20190409091529.2686-1-rikard.falkeborn@gmail.com> References: <20190409091529.2686-1-rikard.falkeborn@gmail.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Hi Rikard, On Tue, 9 Apr 2019 11:15:29 +0200 Rikard Falkeborn wrote: > There was a missing comparison with 0 when checking if type is "s64" or > "u64". Therefore, the body of the if-statement was entered if "type" was > "u64" or not "s64", which made the first strcmp() redundant since if > type is "u64", it's not "s64". > > If type is "s64", the body of the if-statement is not entered but since the > remainder of the function consists of if-statements which will not be > entered if type is "s64", we will just return "val", which is correct, > albeit at the cost of a few more calls to strcmp(), i.e., it will behave > just as if the if-statement was entered. > > If type is neither "s64" or "u64", the body of the if-statement will be > entered incorrectly and "val" returned. This means that any type that is > checked after "s64" and "u64" is handled the same way as "s64" and > "u64", i.e., the limiting of "val" to fit in for example "s8" is never > reached. > > This was introduced in the kernel tree when the sources were copied from > trace-cmd in commit f7d82350e597 ("tools/events: Add files to create > libtraceevent.a"), and in the trace-cmd repo in 1cdbae6035cei ("Implement > typecasting in parser") when the function was introduced, i.e., it has > always behaved the wrong way. > > Detected by cppcheck. Nice. Thanks for this. > > Fixes: f7d82350e597 ("tools/events: Add files to create libtraceevent.a") > Signed-off-by: Rikard Falkeborn Reviewed-by: Steven Rostedt (VMware) Arnaldo, Care to pull this in? Thanks! -- Steve > --- > I have only compile tested the patch but it should be correct. I don't > know if any other problems will surface due to this though. > --- > tools/lib/traceevent/event-parse.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c > index 87494c7c619d..981c6ce2da2c 100644 > --- a/tools/lib/traceevent/event-parse.c > +++ b/tools/lib/traceevent/event-parse.c > @@ -2233,7 +2233,7 @@ eval_type_str(unsigned long long val, const char *type, int pointer) > return val & 0xffffffff; > > if (strcmp(type, "u64") == 0 || > - strcmp(type, "s64")) > + strcmp(type, "s64") == 0) > return val; > > if (strcmp(type, "s8") == 0)