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Date: Wed, 3 Apr 2019 18:59:51 +0000
From: Song Liu <songliubraving@...com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
CC: Jiri Olsa <jolsa@...hat.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Andi Kleen <andi@...stfloor.org>,
"jolsa@...nel.org" <jolsa@...nel.org>,
"namhyung@...nel.org" <namhyung@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-perf-users@...r.kernel.org" <linux-perf-users@...r.kernel.org>,
Andi Kleen <ak@...ux.intel.com>
Subject: Re: [BUG] perf: intel_pt won't display kernel function
> On Apr 3, 2019, at 11:55 AM, Song Liu <songliubraving@...com> wrote:
>
>
>
>> On Apr 3, 2019, at 11:50 AM, Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> wrote:
>>
>> Em Wed, Apr 03, 2019 at 04:27:56PM +0000, Song Liu escreveu:
>>>
>>>
>>>> On Apr 3, 2019, at 8:15 AM, Arnaldo Carvalho de Melo <arnaldo.melo@...il.com> wrote:
>>>>
>>>> Em Wed, Apr 03, 2019 at 11:53:53AM -0300, Arnaldo Carvalho de Melo escreveu:
>>>>> Em Wed, Apr 03, 2019 at 04:37:38PM +0200, Jiri Olsa escreveu:
>>>>>> hi,
>>>>>> perf script --call-trace stop working for me recently,
>>>>>> and displays only user space functions
>>>>>>
>>>>>> I bisected that to:
>>>>>> 7b612e291a5a perf tools: Synthesize PERF_RECORD_* for loaded BPF programs
>>>>>>
>>>>>> data from following comands will display user space functions only:
>>>>>> # perf-with-kcore record pt -e intel_pt// -- ls
>>>>>> # perf-with-kcore script pt --call-trace
>>>>>>
>>>>>> when I disable the bpf synthesizing (patch below), kernel functions are back
>>>>>>
>>>>>> I guess the new events mess up with intel_pt decoder somehow
>>>>>
>>>>> I.e. I'm adding the patch below to my perf/urgent branch.
>>>>
>>>> Song, that is what I have, can I have your Acked-by and please consider
>>>> taking a look at the bug Jiri reported,
>>>>
>>>> Thanks,
>>>>
>>>> - Arnaldo
>>>
>>> Current logic with --no-bpf-event is to generate PERF_RECORD_KSYMBOL, but not
>>> PERF_RECORD_BPF_EVENT:
>>
>> I see... The opts is done later, after querying the kernel for existing
>> BPF programs so that at least the KSYMBOL ones can be generated. So I'll
>> keep it as is, no need for this patch.
>>
>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__elixir.bootlin.com_linux_v5.1-2Drc3_source_tools_perf_util_bpf-2Devent.c-23L254&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=dR8692q0_uaizy0jkrBJQM5k2hfm4CiFxYT8KaysFrg&m=8ITYgIrqFBIy1uQFQPHrsX5kBX5RlmhwcknKYJa2eGs&s=MdB2zA9JstwC93qKEonsfTQeQYiw-yeOLbPxm3QMRo8&e=
>>>
>>> I will look into the intel_pt problem.
>>
>> Ok.
>>
>>> In the meanwhile, let's fix it for now.
>>
>> I'll wait a bit.
>
> I guess something like this might be a better fix? (Sorry for missing
> commit message):
>
> diff --git i/tools/perf/util/map.c w/tools/perf/util/map.c
> index e32628cd20a7..741430a35dca 100644
> --- i/tools/perf/util/map.c
> +++ w/tools/perf/util/map.c
> @@ -261,6 +261,12 @@ bool __map__is_extra_kernel_map(const struct map *map)
> return kmap && kmap->name[0];
> }
>
> +bool __map__is_bpf_prog(const struct map *map)
> +{
> + const char *name = map->dso->short_name;
> + return name && (strstr(name, "bpf_prog_") == name);
> +}
> +
> bool map__has_symbols(const struct map *map)
> {
> return dso__has_symbols(map->dso);
> diff --git i/tools/perf/util/map.h w/tools/perf/util/map.h
> index 0e20749f2c55..01079f1f4375 100644
> --- i/tools/perf/util/map.h
> +++ w/tools/perf/util/map.h
> @@ -159,10 +159,12 @@ int map__set_kallsyms_ref_reloc_sym(struct map *map, const char *symbol_name,
>
> bool __map__is_kernel(const struct map *map);
> bool __map__is_extra_kernel_map(const struct map *map);
> +bool __map__is_bpf_prog(const struct map *map);
>
> static inline bool __map__is_kmodule(const struct map *map)
> {
> - return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map);
> + return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map) &&
> + !__map__is_bpf_prog(map);
> }
>
> bool map__has_symbols(const struct map *map);
>
> Thanks,
> Song
Actually, it should be something like this:
diff --git i/tools/perf/util/map.c w/tools/perf/util/map.c
index e32628cd20a7..31cd23612529 100644
--- i/tools/perf/util/map.c
+++ w/tools/perf/util/map.c
@@ -261,6 +261,11 @@ bool __map__is_extra_kernel_map(const struct map *map)
return kmap && kmap->name[0];
}
+bool __map__is_bpf_prog(const struct map *map)
+{
+ return map->dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO;
+}
+
bool map__has_symbols(const struct map *map)
{
return dso__has_symbols(map->dso);
diff --git i/tools/perf/util/map.h w/tools/perf/util/map.h
index 0e20749f2c55..01079f1f4375 100644
--- i/tools/perf/util/map.h
+++ w/tools/perf/util/map.h
@@ -159,10 +159,12 @@ int map__set_kallsyms_ref_reloc_sym(struct map *map, const char *symbol_name,
bool __map__is_kernel(const struct map *map);
bool __map__is_extra_kernel_map(const struct map *map);
+bool __map__is_bpf_prog(const struct map *map);
static inline bool __map__is_kmodule(const struct map *map)
{
- return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map);
+ return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map) &&
+ !__map__is_bpf_prog(map);
}
bool map__has_symbols(const struct map *map);
>
>>
>>> Acked-by: Song Liu <songliubraving@...com>
>>>
>>> Thanks,
>>> Song
>>>
>>>
>>>> commit 011318ccc2024ba03e96c32a06f74ca5d6ab5503
>>>> Author: Arnaldo Carvalho de Melo <acme@...hat.com>
>>>> Date: Wed Apr 3 12:05:15 2019 -0300
>>>>
>>>> perf record: Do not synthesize BPF records when --no-bpf-event is used
>>>>
>>>> By default we synthesize and ask the kernel for BPF events, having a
>>>> --no-bpf-event option to disable that, which can be useful, for
>>>> instance, if there are still bugs in that code, which seems to be the
>>>> case as reported by Jiri Olsa in:
>>>>
>>>> "[BUG] perf: intel_pt won't display kernel function"
>>>> https://lore.kernel.org/lkml/20190403143738.GB32001@krava
>>>>
>>>> So add the check for record_opts.no_bpf_event when considering
>>>> synthesizing BPF events for pre-existing BPF programs in 'perf record'.
>>>>
>>>> The reported bug needs further analysis and is a separate matter.
>>>>
>>>> Cc: Adrian Hunter <adrian.hunter@...el.com>
>>>> Cc: Alexei Starovoitov <ast@...nel.org>
>>>> Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
>>>> Cc: Daniel Borkmann <daniel@...earbox.net>
>>>> Cc: Jiri Olsa <jolsa@...nel.org>
>>>> Cc: Martin KaFai Lau <kafai@...com>
>>>> Cc: Namhyung Kim <namhyung@...nel.org>
>>>> Cc: Peter Zijlstra <peterz@...radead.org>
>>>> Cc: Song Liu <songliubraving@...com>
>>>> Cc: Yonghong Song <yhs@...com>
>>>> Fixes: 7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs")
>>>> Link: https://lore.kernel.org/lkml/20190403145353.GE32553@kernel.org
>>>> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
>>>>
>>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>>>> index 4e2d953d4bc5..17d772f192ad 100644
>>>> --- a/tools/perf/builtin-record.c
>>>> +++ b/tools/perf/builtin-record.c
>>>> @@ -1114,10 +1114,11 @@ static int record__synthesize(struct record *rec, bool tail)
>>>> return err;
>>>> }
>>>>
>>>> - err = perf_event__synthesize_bpf_events(session, process_synthesized_event,
>>>> - machine, opts);
>>>> - if (err < 0)
>>>> - pr_warning("Couldn't synthesize bpf events.\n");
>>>> + if (!opts->no_bpf_event) {
>>>> + err = perf_event__synthesize_bpf_events(session, process_synthesized_event, machine, opts);
>>>> + if (err < 0)
>>>> + pr_warning("Couldn't synthesize bpf events.\n");
>>>> + }
>>>>
>>>> err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads,
>>>> process_synthesized_event, opts->sample_address,
>>
>> --
>>
>> - Arnaldo
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