From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966114AbcHDTja (ORCPT ); Thu, 4 Aug 2016 15:39:30 -0400 Received: from mail.kernel.org ([198.145.29.136]:40680 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965896AbcHDThC (ORCPT ); Thu, 4 Aug 2016 15:37:02 -0400 Date: Thu, 4 Aug 2016 16:36:56 -0300 From: Arnaldo Carvalho de Melo To: Masami Hiramatsu Cc: "Wangnan (F)" , Linux Kernel Mailing List Subject: Re: perf test BPF failing on f24: fix Message-ID: <20160804193656.GK14639@kernel.org> References: <20160802195102.GD14639@kernel.org> <57A1A913.6000307@huawei.com> <20160803234557.29f43f755b7e14c634a54a9a@kernel.org> <20160803200415.GG14639@kernel.org> <20160804153221.8aa29dfc5533b14089bd7470@kernel.org> <20160804124857.GH14639@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160804124857.GH14639@kernel.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Thu, Aug 04, 2016 at 09:48:57AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Aug 04, 2016 at 03:32:21PM +0900, Masami Hiramatsu escreveu: > > FYI, if perf-probe failed to find the symbol in debuginfo, it tries to find its address > > from symbol table(kallsyms, here), and then tries to convert the address to the symbol > > in debuginfo again. It seems that in your case this convert process is failed. > Yeah, that is what is failing for me. [root@jouet ~]# grep ffffffffbd295b50 /proc/kallsyms ffffffffbd295b50 T SyS_epoll_wait ffffffffbd295b50 T sys_epoll_wait [root@jouet ~]# Adding some printfs in debuginfo__find_probe_point() Using /lib/modules/4.7.0+/build/vmlinux for symbols Open Debuginfo file: /lib/modules/4.7.0+/build/vmlinux Try to find probe point from debuginfo. Symbol sys_epoll_wait address found : ffffffffbd295b50 dwarf_addrdie(ffffffffbd295b50) dwarf_addrdie(ffffffffbd295b50) Failed to find debug information for address ffffffffbd295b50 Probe point 'sys_epoll_wait' not found. Error: Failed to add events. Reason: No such file or directory (Code: -2) [root@jouet ~]# grep ffffffffbd295b50 /proc/kallsyms ffffffffbd295b50 T SyS_epoll_wait ffffffffbd295b50 T sys_epoll_wait [root@jouet ~]# So: int err = debuginfo__get_text_offset(dbg, &baseaddr); is returning 0, no relocation, its dwarf_addrdie() that is not finding SyS_epoll_wait from its address. Trying to figure out why dwarf_addrdie(0xffffffffbd295b50) fails... - Arnaldo > > Then, could you grep DEBUG_INFO in .config? I guess your kernel enables some > > reduced debuginfo related config enabled... > If that is the case, then we better add a proper warning because this is > very subtle :-) > Checking... > [acme@jouet linux]$ grep ^CONFIG_DEBUG_ ../build/v4.7.0+/.config | grep 'INFO\|REDUCED' > CONFIG_DEBUG_INFO=y > [acme@jouet linux]$ > > Nope. > > - Arnaldo