From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751980AbbIXI32 (ORCPT ); Thu, 24 Sep 2015 04:29:28 -0400 Received: from m50-135.163.com ([123.125.50.135]:56050 "EHLO m50-135.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbbIXI3Y convert rfc822-to-8bit (ORCPT ); Thu, 24 Sep 2015 04:29:24 -0400 Content-Type: text/plain; charset=gb2312 Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] perf probe: Fix module probing with shortname From: pi3orama X-Mailer: iPhone Mail (13A344) In-Reply-To: <20150924020553.GF1897@kernel.org> Date: Thu, 24 Sep 2015 16:28:35 +0800 Cc: "Wangnan (F)" , linux-kernel@vger.kernel.org, lizefan@huawei.com, Namhyung Kim , Jiri Olsa , Masami Hiramatsu Content-Transfer-Encoding: 8BIT Message-Id: <5FD91EBA-72CD-4212-9219-631C48E1648C@163.com> 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> <20150924015008.GE1897@kernel.org> <20150924020553.GF1897@kernel.org> To: Arnaldo Carvalho de Melo X-CM-TRANSID: D9GowAC3GfQztANWjI1ECQ--.12026S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxAF4fXFWfKw48Cr15Wr4xCrg_yoWrKFWrpr 95CF4YkF4UJr4Yq3WFy3W8ZrySvrWrXr4jgrn8GrWfAF1q9FnrWF1I9w1a9F4Ykr4kKr12 vr10q34aq34UJa7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j1ApnUUUUU= X-Originating-IP: [103.14.185.15] X-CM-SenderInfo: lslt02xdpdqiywtou0bp/1tbiNBZ-QFC-JFdIPwAAs2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 发自我的 iPhone > 在 2015年9月24日，上午10:05，Arnaldo Carvalho de Melo 写道： > > Em Wed, Sep 23, 2015 at 10:50:08PM -0300, Arnaldo Carvalho de Melo escreveu: >> 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: > That's good, but the meaning of dso->kernel is still confusing. However, since the problem is solved, do you still think it should be fixed? Thank you. > Using it: > > > [root@zoo ~]# perf probe -v -m usbnet --add usbnet_start_xmit > probe-definition(0): usbnet_start_xmit > symbol:usbnet_start_xmit file:(null) line:0 offset:0 return:0 lazy:(null) > 0 arguments > Open Debuginfo file: /lib/modules/4.3.0-rc1+/kernel/drivers/net/usb/usbnet.ko > Try to find probe point from debuginfo. > Matched function: usbnet_start_xmit > Probe point found: usbnet_start_xmit+0 > Found 1 probe_trace_events. > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Writing event: p:probe/usbnet_start_xmit usbnet:usbnet_start_xmit+0 > Added new event: > probe:usbnet_start_xmit (on usbnet_start_xmit in usbnet) > > You can now use it in all perf tools, such as: > > perf record -e probe:usbnet_start_xmit -aR sleep 1 > > [root@zoo ~]# > > ot@zoo ~]# perf probe -m kvm --add apic_has_pending_timer > Added new event: > probe:apic_has_pending_timer (on apic_has_pending_timer in kvm) > > You can now use it in all perf tools, such as: > > perf record -e probe:apic_has_pending_timer -aR sleep 1 > > [root@zoo ~]# > > [root@zoo ~]# perf probe -m kvm -F ioapic* > ioapic_mmio_read > ioapic_mmio_write > ioapic_service > ioapic_set_irq > [root@zoo ~]# > > [root@zoo ~]# perf probe -m mac80211 -F 'i*_tx_*' | head -10 > ieee80211_add_tx_ts > ieee80211_agg_tx_operational > ieee80211_clear_tx_pending > ieee80211_del_tx_ts > ieee80211_get_key_tx_seq > ieee80211_get_tx_power > ieee80211_get_tx_rates > ieee80211_init_tx_queue > ieee80211_mgd_conn_tx_status > ieee80211_mgmt_tx_cancel_wait > [root@zoo ~]# > > - Arnaldo > > >> 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;