From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753733AbbFMB3q (ORCPT ); Fri, 12 Jun 2015 21:29:46 -0400 Received: from smtprelay0199.hostedemail.com ([216.40.44.199]:42384 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751104AbbFMB3p (ORCPT ); Fri, 12 Jun 2015 21:29:45 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::,RULES_HIT:41:355:379:541:599:800:960:968:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3871:3872:3873:3874:4362:4470:5007:6119:6261:7875:7903:10004:10400:10848:10967:11026:11232:11473:11658:11914:12043:12438:12517:12519:12663:12740:13069:13161:13229:13311:13357:14096:14097:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: knife21_8f14adae0c434 X-Filterd-Recvd-Size: 2209 Date: Fri, 12 Jun 2015 21:29:42 -0400 From: Steven Rostedt To: Vince Weaver Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo Subject: Re: perf,ftrace: fuzzer triggers warning in trace_events_filter code Message-ID: <20150612212942.3b834558@gandalf.local.home> In-Reply-To: References: <20150612174045.1e9b0ca0@gandalf.local.home> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 12 Jun 2015 21:15:10 -0400 (EDT) Vince Weaver wrote: > On Fri, 12 Jun 2015, Steven Rostedt wrote: > > > On Fri, 12 Jun 2015 17:18:22 -0400 (EDT) > > Vince Weaver wrote: > > > > > > > > So I've modified my fuzzer to try to exercise the > > > PERF_EVENT_IOC_SET_FILTER ioctl() and it is starting to turn up some > > > warnings. > > > > Is there any way to know what the filter string you used that generated > > this? > > Various seem to trigger it. One example is > > ext4:ext4_truncate_exit > (((dev<=913)blocks==916)common_type&756) > Thanks, OK, I know what the issue is. I'm also thinking the solution may simply be removing that WARN_ON(). But I'll look at it a little deeper before deciding that. The WARN_ON() simply detected an anomaly, but nothing breaks when that anomaly occurs. Well, I don't see anything breaking, it just expected that we couldn't get to this path, but now we know we can. Thus the solution is to remove the WARN_ON() or detect the bad filter before getting there. -- Steve