From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757015AbcHBTwI (ORCPT ); Tue, 2 Aug 2016 15:52:08 -0400 Received: from mail.kernel.org ([198.145.29.136]:53806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750961AbcHBTvj (ORCPT ); Tue, 2 Aug 2016 15:51:39 -0400 Date: Tue, 2 Aug 2016 16:51:02 -0300 From: Arnaldo Carvalho de Melo To: Wang Nan Cc: Linux Kernel Mailing List Subject: perf test BPF failing on f24: fix Message-ID: <20160802195102.GD14639@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 Hi Wang, Something changed and a function used in a perf test for BPF is not anymore appearing on vmlinux, albeit still available on /proc/kallsyms: # readelf -wi /lib/modules/4.7.0+/build/vmlinux | grep -w sys_epoll_wait # But: [root@jouet ~]# grep -i sys_epoll_wait /proc/kallsyms ffffffffbd295b50 T SyS_epoll_wait ffffffffbd295b50 T sys_epoll_wait [root@jouet ~]# I noticed that it is some sort of aliasing so I checked the other variant: [root@jouet ~]# readelf -wi /lib/modules/4.7.0+/build/vmlinux | grep -w SyS_epoll_wait <2bc9b85> DW_AT_name : (indirect string, offset: 0xe7524): SyS_epoll_wait [root@jouet ~]# Trying to use perf probe also produces the same resuls I notice when running the perf test that is failing: [root@jouet ~]# perf probe sys_epoll_wait Failed to find debug information for address ffffffffbd295b50 Probe point 'sys_epoll_wait' not found. Error: Failed to add events. [root@jouet ~]# perf probe SyS_epoll_wait Added new events: probe:SyS_epoll_wait (on SyS_epoll_wait) probe:SyS_epoll_wait_1 (on SyS_epoll_wait) probe:SyS_epoll_wait_2 (on SyS_epoll_wait) You can now use it in all perf tools, such as: perf record -e probe:SyS_epoll_wait_2 -aR sleep 1 [root@jouet ~]# So I am changing the BPF perf test to use the CamelCase notation alias: Failing (with sys_epoll_wait): [root@jouet ~]# perf test BPF 37: Test BPF filter : 37.1: Test basic BPF filtering : FAILED! 37.2: Test BPF prologue generation : Skip 37.3: Test BPF relocation checker : Skip [root@jouet ~]# Changing to (SyS_epoll_wait): [root@jouet ~]# perf test BPF 37: Test BPF filter : 37.1: Test basic BPF filtering : Ok 37.2: Test BPF prologue generation : Ok 37.3: Test BPF relocation checker : Ok [root@jouet ~]# I'm adding a fix that just makes it use SyS_epoll_wait. - Arnaldo