Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753118AbbGGDx5 (ORCPT ); Mon, 6 Jul 2015 23:53:57 -0400 Received: from mail-ig0-f169.google.com ([209.85.213.169]:34756 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751300AbbGGDxx (ORCPT ); Mon, 6 Jul 2015 23:53:53 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Tue, 7 Jul 2015 00:00:12 -0400 (EDT) To: Masami Hiramatsu cc: Vince Weaver , linux-kernel@vger.kernel.org, Ananth N Mavinakayanahalli , Anil S Keshavamurthy , "David S. Miller" , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Steven Rostedt Subject: Re: perf, kprobes: fuzzer generates huge number of WARNings In-Reply-To: <559B3899.5040802@hitachi.com> Message-ID: References: <559B3899.5040802@hitachi.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1573 Lines: 39 On Tue, 7 Jul 2015, Masami Hiramatsu wrote: > On 2015/07/07 6:27, Vince Weaver wrote: > > Hello > > > > I've been working on trying to get the perf_fuzzer to start fuzzing the > > PERF_EVENT_IOC_SET_BPF so I've added some really hackish kprobe support. > > > > However before I can get to the BPF testing the kprobe code generates a > > constant stream of WARNINGS which make the machine more or less useless > > until I stop it. I've included a small selection here. > > > > Is this expected? > > Did you get same message without BPF hack? And also, could you tell us > your kernel version and configuration? It's a Hawell machine running 4.2-rc1. I can post the .config if it's of interest. Well the BPF hack is in the fuzzer, not the kernel. And it's not really a hack, it just turned out to be a huge pain to figure out how to manually create a valid BPF program in conjunction with a valid kprobe event. I did have to sprinkle printks in the kprobe and bpf code to find out where various EINVAL returns were coming from, so potentially this is just a problem of printks happening where they shouldn't. I'll remove those changes and try to reproduce this tomorrow. This is possibly a long standing issue, until now I never ran the fuzzer as root so these particular code paths weren't tested. Vince -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/