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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 E78FAC433DF for ; Thu, 6 Aug 2020 19:44:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2E112177B for ; Thu, 6 Aug 2020 19:44:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QSoFgVDq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726293AbgHFToN (ORCPT ); Thu, 6 Aug 2020 15:44:13 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:43679 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725947AbgHFToM (ORCPT ); Thu, 6 Aug 2020 15:44:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596743051; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=W0++OTxXTfk2wjvHLjiHnZibQfFxJzlhhcpK1AT+7Ig=; b=QSoFgVDq2DBUxAQI3g4mL4WfjW4lI6zf5BKwjTbsJJa9spa4XGlCa2JZyB7P5VC2sQUJVY cnYFl3llB8DSkGmZ1cvrYxFvRt++i0MG5j+oxerPte8AYvAplPZaVCM68iNlhZGCb/1KC+ /jdMZE3DK6R3turFKbXBVGDlTWLEWdM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-436-XlM89QQdNsC8WHHcK82uFQ-1; Thu, 06 Aug 2020 15:44:07 -0400 X-MC-Unique: XlM89QQdNsC8WHHcK82uFQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D2D9A102C7EC; Thu, 6 Aug 2020 19:44:05 +0000 (UTC) Received: from krava (unknown [10.40.192.156]) by smtp.corp.redhat.com (Postfix) with SMTP id B49CB87A61; Thu, 6 Aug 2020 19:44:03 +0000 (UTC) Date: Thu, 6 Aug 2020 21:43:57 +0200 From: Jiri Olsa To: Jin Yao Cc: acme@kernel.org, jolsa@kernel.org, peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com Subject: Re: [PATCH] perf record: Skip side-band event setup if HAVE_LIBBPF_SUPPORT is not set Message-ID: <20200806194357.GA539212@krava> References: <20200805022937.29184-1-yao.jin@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200805022937.29184-1-yao.jin@linux.intel.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 05, 2020 at 10:29:37AM +0800, Jin Yao wrote: > We received an error report that perf-record caused 'Segmentation fault' > on a newly system (e.g. on the new installed ubuntu). > > (gdb) backtrace > #0 __read_once_size (size=4, res=, p=0x14) at /root/0-jinyao/acme/tools/include/linux/compiler.h:139 > #1 atomic_read (v=0x14) at /root/0-jinyao/acme/tools/include/asm/../../arch/x86/include/asm/atomic.h:28 > #2 refcount_read (r=0x14) at /root/0-jinyao/acme/tools/include/linux/refcount.h:65 > #3 perf_mmap__read_init (map=map@entry=0x0) at mmap.c:177 > #4 0x0000561ce5c0de39 in perf_evlist__poll_thread (arg=0x561ce68584d0) at util/sideband_evlist.c:62 > #5 0x00007fad78491609 in start_thread (arg=) at pthread_create.c:477 > #6 0x00007fad7823c103 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 hum, I recall discussing the same issue, I thought it was already fixed :-\ in any case: Acked-by: Jiri Olsa thanks, jirka > > The root cause is, evlist__add_bpf_sb_event() just returns 0 if > HAVE_LIBBPF_SUPPORT is not defined (inline function path). So it will > not create a valid evsel for side-band event. > > But perf-record still creates BPF side band thread to process the > side-band event, then the error happpens. > > We can reproduce this issue by removing the libelf-dev. e.g. > 1. apt-get remove libelf-dev > 2. perf record -a -- sleep 1 > > root@test:~# ./perf record -a -- sleep 1 > perf: Segmentation fault > Obtained 6 stack frames. > ./perf(+0x28eee8) [0x5562d6ef6ee8] > /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7fbfdc65f210] > ./perf(+0x342e74) [0x5562d6faae74] > ./perf(+0x257e39) [0x5562d6ebfe39] > /lib/x86_64-linux-gnu/libpthread.so.0(+0x9609) [0x7fbfdc990609] > /lib/x86_64-linux-gnu/libc.so.6(clone+0x43) [0x7fbfdc73b103] > Segmentation fault (core dumped) > > To fix this issue, > > 1. We either install the missing libraries to let HAVE_LIBBPF_SUPPORT > be defined. > e.g. apt-get install libelf-dev and install other related libraries. > > 2. Use this patch to skip the side-band event setup if HAVE_LIBBPF_SUPPORT > is not set. > > Signed-off-by: Jin Yao > --- > tools/perf/builtin-record.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index b6bdccd875bc..ae97f98e2753 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1506,6 +1506,7 @@ static int record__synthesize(struct record *rec, bool tail) > return err; > } > > +#ifdef HAVE_LIBBPF_SUPPORT > static int record__process_signal_event(union perf_event *event __maybe_unused, void *data) > { > struct record *rec = data; > @@ -1550,6 +1551,12 @@ static int record__setup_sb_evlist(struct record *rec) > > return 0; > } > +#else > +static int record__setup_sb_evlist(struct record *rec __maybe_unused) > +{ > + return 0; > +} > +#endif > > static int __cmd_record(struct record *rec, int argc, const char **argv) > { > -- > 2.17.1 >