[lttng-dev] Help needed: No UST events recorded

[PFLANZER Moritz]

Hi Jonathan,

Apologies that I forgot to mention which version of LTTng I'm using. I didn't build from master but downloaded the latest release archives for LTTng 2.12 "(Ta) Meilleure". "lttng --version" reports a corresponding "lttng (LTTng Trace Control) 2.12.1 - (Ta) Meilleure"

Please find the console log here: https://pastebin.com/PVzqrPvr
and the lttng-sessiond.log here: https://pastebin.com/g3aXAcQg

Thanks,
Moritz



Moritz Pflanzer
Software Development Engineer

[cid:image001.png at 01D3BF6E.185110B0]

Räffelstrasse 28

8045 Zürich
E: moritz.pflanzer at hexagon.com<mailto:moritz.pflanzer at hexagon.com><mailto:carolin.siebert at hexagon.com>
W: http://www.hexagongeosystems.com

________________________________
From: Jonathan Rajotte-Julien <jonathan.rajotte-julien at efficios.com>
Sent: 03 August 2020 17:31
To: PFLANZER Moritz <moritz.pflanzer at hexagon.com>
Cc: lttng-dev at lists.lttng.org <lttng-dev at lists.lttng.org>
Subject: Re: [lttng-dev] Help needed: No UST events recorded

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Hi Moritz

What is your version of lttng-tools?

  lttng --version

Please run the `hello` executable using the LTTNG_UST_DEBUG env variable, while
tracing, and provide the output.

  pkill lttng-sessiond
  lttng-sessiond -b -vvv --verbose-consumer 2> /tmp/lttng-sessiond.log
  lttng create
  lttng enable-event -u -a
  lttng start
  LTTNG_UST_DEBUG=y ./hello
  lttng stop
  lttng destroy
  pkill lttng-sessiond

Please also provide the /tmp/lttng-sessiond.log file via pastebin.

I suspect that if you cross-compiled lttng-ust from the master branch that
lttng-tools is not using the same version, resulting in the application not
being able to register to the lttng-sessiond.

Cheers

On Mon, Aug 03, 2020 at 09:35:25AM +0000, PFLANZER Moritz via lttng-dev wrote:
> Hi all!
>
> I'm struggling to get userspace tracing working on an aarch64 platform (busybox on top of Linux 5.4.24 kernel). I followed the guidelines in the docs and am currently using this example program for testing: https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Flttng%2Flttng-ust%2Ftree%2Fmaster%2Fdoc%2Fexamples%2Fhello-static-lib&data=02%7C01%7C%7Ce141a6eb68ea4d4c93c508d837c25b99%7C1b16ab3eb8f64fe39f3e2db7fe549f6a%7C0%7C0%7C637320655210160415&sdata=lPbFWob0G4U22ncUmqfz12Ha42xOymctYWCOJC34oC8%3D&reserved=0
> I cross-compiled lttng-ust and that example, but when I run the following commands on the platform no traces are recorded. If I use the same example on my x86 machine everything works as expected. (And kernelspace tracing is working on that aarch64 system.)
>
> Any hints where I could start investigating the issue are welcome.
>
> Regards,
> Moritz
>
> ~ # pwd
> /root
> ~ # lttng create
> Spawning a session daemon
> Session auto-20200720-174509 created.
> Traces will be written in /root/lttng-traces/auto-20200720-174509
> ~ # lttng enable-event -au
> All UST events are enabled in channel channel0
> ~ # lttng start
> Tracing started for session auto-20200720-174509
> ~ # ./hello
> Hello, World!
> Tracing...  done.
> ~ # lttng destroy
> Session auto-20200720-174509 destroyed
> ~ # ll
> total 40
> -rwxr-xr-x    1 root     root         39280 Jul 20 17:44 hello*
>
>
>
> Moritz Pflanzer
> Software Development Engineer
>
> [cid:image001.png at 01D3BF6E.185110B0]
>
> Räffelstrasse 28
>
> 8045 Zürich
> E: moritz.pflanzer at hexagon.com<mailto:moritz.pflanzer at hexagon.com><mailto:carolin.siebert at hexagon.com>
> W: http://www.hexagongeosystems.com/



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--
Jonathan Rajotte-Julien
EfficiOS
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