linux-kernel - Re: [PATCH 11/11] perf tools: Stop fallbacking to kallsyms for vdso symbols lookup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87bm7fgnhz.fsf@intel.com>
Date:   Sat, 27 Oct 2018 13:09:44 -0700
From:   Vinicius Costa Gomes <vinicius.gomes@...el.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Clark Williams <williams@...hat.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        David Ahern <dsahern@...il.com>, Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH 11/11] perf tools: Stop fallbacking to kallsyms for vdso symbols lookup

Hi Jirka,

Jiri Olsa <jolsa@...hat.com> writes:

> On Fri, Oct 26, 2018 at 04:19:52PM -0700, Vinicius Costa Gomes wrote:
>> Hi,
>> 
>> Adrian Hunter <adrian.hunter@...el.com> writes:
>> 
>> > On 18/10/18 1:55 AM, Arnaldo Carvalho de Melo wrote:
>> >> From: Arnaldo Carvalho de Melo <acme@...hat.com>
>> >> 
>> >> David reports that:
>> >> 
>> >> <quote>
>> >> Perf has this hack where it uses the kernel symbol map as a backup when
>> >> a symbol can't be found in the user's symbol table(s).
>> >
>> > I don't think this is a complete fix because it exposes new problems.
>> 
>> This commit broke function name resolution for 'perf record -g' for me.
>> 
>> What I mean is, with this commit applied:
>> 
>> $ ./tools/perf/perf record -g -- sleep 1
>> 
>> $ ./tools/perf/perf report
>> 
>> 'perf report' doesn't seem to be able to show the function names of the
>> trace.
>> 
>> If I revert this commit, function names are resolved fine.
>
> that commit just showed up some places where we have the
> ip resolve wrong.. would attached patch fix it for you?

Thank you for your patch.

I can some difference in the output, but I wouldn't say that it's fixed.

Here are some samples, if it's useful somehow:

https://gist.github.com/vcgomes/985626705e0968b973e426964f86a4b0

The "ping" tests were done running

$ sudo ./tools/perf/perf record -g -- ping -f -c 1000 127.0.0.1

And the "sleep" tests were done running

$ sudo ./tools/perf/perf record -g -- /bin/sleep 1


--
Vinicius