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Date: Wed, 23 Sep 2015 23:05:53 -0300 From: Arnaldo Carvalho de Melo <acme@...nel.org> To: "Wangnan (F)" <wangnan0@...wei.com> Cc: linux-kernel@...r.kernel.org, lizefan@...wei.com, pi3orama@....com, Namhyung Kim <namhyung@...nel.org>, Jiri Olsa <jolsa@...hat.com>, Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> Subject: Re: [PATCH] perf probe: Fix module probing with shortname 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: 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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