From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932482AbbIXBuR (ORCPT ); Wed, 23 Sep 2015 21:50:17 -0400 Received: from mail.kernel.org ([198.145.29.136]:55495 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932095AbbIXBuO (ORCPT ); Wed, 23 Sep 2015 21:50:14 -0400 Date: Wed, 23 Sep 2015 22:50:08 -0300 From: Arnaldo Carvalho de Melo To: "Wangnan (F)" Cc: linux-kernel@vger.kernel.org, lizefan@huawei.com, pi3orama@163.com, Namhyung Kim , Jiri Olsa , Masami Hiramatsu Subject: Re: [PATCH] perf probe: Fix module probing with shortname Message-ID: <20150924015008.GE1897@kernel.org> References: <1442892872-33708-1-git-send-email-wangnan0@huawei.com> <20150922133504.GA2580@redhat.com> <5601FD04.4060108@huawei.com> <20150923024902.GA5041@redhat.com> <20150923160319.GG5041@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150923160319.GG5041@redhat.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Sep 23, 2015 at 01:03:19PM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Sep 22, 2015 at 11:49:02PM -0300, Arnaldo Carvalho de Melo escreveu: > > Em Wed, Sep 23, 2015 at 09:14:44AM +0800, Wangnan (F) escreveu: > > > On 2015/9/22 21:35, Arnaldo Carvalho de Melo wrote: > > > >Em Tue, Sep 22, 2015 at 03:34:32AM +0000, Wang Nan escreveu: > > > >>This is caused by a misunderstood of dso->kernel in kernel_get_module_dso() > > > >>that, for kernel module, dso->kernel is DSO_TYPE_USER. dso->kernel is DSO_TYPE_KERNEL > > > >>iff dso is vmlinux. > > > >Kernel modules having DSO_TYPE_USER seems to be the bug, no? I'll try to > > > >check that... > > > I also noticed this problem when I working on commit > > > 1f121b03d058dd07199d8924373d3c52a207f63b ("perf tools: Deal with > > > kernel module names in '[]' correctly") ;) > > Thanks for working on this, it is an area that needs cleaning up, too > > many ways to say what a dso is, will study your findings and try to come > > up with a patch proposal tomorrow. > > > So care must be taken. > > So, yes, there are multiple uses for this dso->kernel thing, we need to > look at each one and go on clarifying it so that this gets corrected and > sane, but I think we need some helpers to clarify all this, namely: > > Adding DSO_TYPE_KMODULE and DSO_TYPE_GUEST_KMODULE, setting > dso->kernel with it when loading host and guest kernel modules and > adding: > > bool dso__is_host_kernel(struct dso *dso) > bool dso__is_host_kmodule(struct dso *dso) > > bool dso__is_guest_kernel(struct dso *dso) So I tried this, ended up basically using __map__is_kernel(), in several places, which I think is right, and I've stashed in my tmp.perf/core branch so that you can take a look. But then I realized that we already have a better way to achieve what is needed in that function, see the patch below, fixed things for me: diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 2b78e8f19b45..7fb0533ab18c 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -269,12 +269,13 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso) int ret = 0; if (module) { - list_for_each_entry(dso, &host_machine->dsos.head, node) { - if (!dso->kernel) - continue; - if (strncmp(dso->short_name + 1, module, - dso->short_name_len - 2) == 0) - goto found; + char module_name[128]; + + snprintf(module_name, sizeof(module_name), "[%s]", module); + map = map_groups__find_by_name(&host_machine->kmaps, MAP__FUNCTION, module_name); + if (map) { + dso = map->dso; + goto found; } pr_debug("Failed to find module %s.\n", module); return -ENOENT;