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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 67411C07E95 for ; Wed, 7 Jul 2021 16:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47A4C61CC6 for ; Wed, 7 Jul 2021 16:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230295AbhGGQd3 (ORCPT ); Wed, 7 Jul 2021 12:33:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:33780 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229519AbhGGQd2 (ORCPT ); Wed, 7 Jul 2021 12:33:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A3B2D61CAC; Wed, 7 Jul 2021 16:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625675448; bh=hFQSmO9JZuU7PCl2e+L0oHy7wyT+9t8i3+Qu5Qji0m0=; h=Subject:From:To:Date:In-Reply-To:References:From; b=dkncukvVxdLVbUB/3nlKeFY/kQGT4V3/rQZ7wcMxI5PX1KTpSOZUNNqZXZ1Azf4q3 0qdWwA3alXlmqklyHXekIUM2c2/s/QZqO9FsohRsyE03YY53lcZB1Jv4dJOoMyINS8 QUvZL0MKmjom4lqUl6+3TpoSVdWxfbj0yaX0QRAAjMdskNvN0oXQHAbnXHNZfzqOmT GjCHT0a4FkvTik31uWBZOYUxNXahl2rBkcSPY9IQ84I8xdG3RbA3pdU0H281NvcvYn XNW4HH/4sUM+LNoCL1oWykNt4vG9SSbUE1CGXYbwh9NeLfDy55Hb6nYH766Jp1Zv1a ovyUV6GRZk7dA== Message-ID: <9769cf1a02fae0be892d6b69cc624eb2b41c1d4d.camel@kernel.org> Subject: Re: [PATCH] tracing/histograms: Fix parsing of "sym-offset" modifier From: Tom Zanussi To: Steven Rostedt , LKML , Ingo Molnar , Andrew Morton , Masami Hiramatsu , Namhyung Kim , Daniel Bristot de Oliveira Date: Wed, 07 Jul 2021 11:30:46 -0500 In-Reply-To: <20210707110821.188ae255@oasis.local.home> References: <20210707110821.188ae255@oasis.local.home> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steve, On Wed, 2021-07-07 at 11:08 -0400, Steven Rostedt wrote: > From: "Steven Rostedt (VMware)" > > With the addition of simple mathematical operations (plus and minus), > the > parsing of the "sym-offset" modifier broke, as it took the '-' part > of the > "sym-offset" as a minus, and tried to break it up into a mathematical > operation of "field.sym - offset", in which case it failed to parse > (unless the event had a field called "offset"). > > Both .sym and .sym-offset modifiers should not be entered into > mathematical calculations anyway. If ".sym-offset" is found in the > modifier, then simply make it not an operation that can be calculated > on. > > Cc: stable@vger.kernel.org > Fixes: 100719dcef447 ("tracing: Add simple expression support to hist > triggers") > Signed-off-by: Steven Rostedt (VMware) > --- > kernel/trace/trace_events_hist.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/trace/trace_events_hist.c > b/kernel/trace/trace_events_hist.c > index ba03b7d84fc2..0207aeed31e6 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -1555,6 +1555,13 @@ static int contains_operator(char *str) > > switch (*op) { > case '-': > + /* > + * Unfortunately, the modifier ".sym-offset" > + * can confuse things. > + */ Good catch. > + if (op - str >= 4 && !strncmp(op - 4, ".sym-offset", > 11)) > + return FIELD_OP_NONE; > + > if (*str == '-') > field_op = FIELD_OP_UNARY_MINUS; > else Reviewed-by: Tom Zanussi