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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 3A3EFC4321D for ; Fri, 24 Aug 2018 00:48:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B42FD21568 for ; Fri, 24 Aug 2018 00:48:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B42FD21568 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726364AbeHXEVC (ORCPT ); Fri, 24 Aug 2018 00:21:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:36328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725951AbeHXEVC (ORCPT ); Fri, 24 Aug 2018 00:21:02 -0400 Received: from vmware.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (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 21A7921557; Fri, 24 Aug 2018 00:48:51 +0000 (UTC) Date: Thu, 23 Aug 2018 20:48:49 -0400 From: Steven Rostedt To: Pavel Tikhomirov Cc: Ingo Molnar , Al Viro , linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Fix event filters and triggers to handle negative numbers Message-ID: <20180823204849.3b4aede3@vmware.local.home> In-Reply-To: <20180823102534.7642-1-ptikhomirov@virtuozzo.com> References: <20180823102534.7642-1-ptikhomirov@virtuozzo.com> X-Mailer: Claws Mail 3.15.1 (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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Aug 2018 13:25:34 +0300 Pavel Tikhomirov wrote: > Then tracing syscall exit event it is extremely useful to filter exit > codes equal to some negative value, to react only to required errors. > But negative numbers does not work: > > [root@snorch sys_exit_read]# echo "ret == -1" > filter > bash: echo: write error: Invalid argument > [root@snorch sys_exit_read]# cat filter > ret == -1 > ^ > parse_error: Invalid value (did you forget quotes)? Thanks for the patch. I'll apply it and then start testing it! -- Steve > > Similar thing happens when setting triggers. > > These is a regression in v4.17 introduced by the commit mentioned below, > testing without these commit shows no problem with negative numbers. > > Fixes: 80765597bc58 ("tracing: Rewrite filter logic to be simpler and faster") > Signed-off-by: Pavel Tikhomirov > --- > kernel/trace/trace_events_filter.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index 84a65173b1e9..2ba449292561 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -1299,7 +1299,7 @@ static int parse_pred(const char *str, void *data, > /* go past the last quote */ > i++; > > - } else if (isdigit(str[i])) { > + } else if (isdigit(str[i]) || str[i] == '-') { > > /* Make sure the field is not a string */ > if (is_string_field(field)) { > @@ -1312,6 +1312,9 @@ static int parse_pred(const char *str, void *data, > goto err_free; > } > > + if (str[i] == '-') > + i++; > + > /* We allow 0xDEADBEEF */ > while (isalnum(str[i])) > i++;