[lttng-dev] Error: opening metadata failed (LTTng on OpenWRT)

[Robin Michielsen]

Hi all,

Any suggestions from anyone on what to check and/or how to debug the issue that I described in my mail from last week?

Kind regards,
Robin

-----Original Message-----
From: jeremie.galarneau at gmail.com [mailto:jeremie.galarneau at gmail.com] On Behalf Of Jérémie Galarneau
Sent: Tuesday, 14 November, 2017 22:14
To: Robin Michielsen
Cc: lttng-dev at lists.lttng.org
Subject: Re: [lttng-dev] Error: opening metadata failed (LTTng on OpenWRT)

On 14 November 2017 at 12:09, Robin Michielsen <robin.michielsen.1 at gmail.com> wrote:
> Hi Jérémie,
>
> Maybe I misunderstood how to create a session, but are the commands that I listed not sufficient for this?
>
> •       lttng create
> •       lttng enable-event --kernel --syscall open,close
> •       lttng start
>

Yes, sorry. I missed it on the first read through.

Jérémie

> Kind regards,
> Robin
>
> -----Original Message-----
> From: jeremie.galarneau at gmail.com [mailto:jeremie.galarneau at gmail.com] 
> On Behalf Of Jérémie Galarneau
> Sent: Tuesday, 14 November, 2017 17:09
> To: Robin Michielsen
> Cc: lttng-dev at lists.lttng.org
> Subject: Re: [lttng-dev] Error: opening metadata failed (LTTng on 
> OpenWRT)
>
> Hi Robin,
>
> Can you add the commands you use to create the session?
>
> Thanks,
> Jérémie
>
> On 14 November 2017 at 04:41, Robin Michielsen <robin.michielsen.1 at gmail.com> wrote:
>> Hi all,
>>
>>
>>
>> I am trying to trace the Linux kernel (system calls) using LTTng on a 
>> platform that is running OpenWRT. I have cross compiled the latest 
>> versions
>> (2.10.x) of the lttng-modules, lttng-tools and lttng-ust packages and 
>> installed these on my OpenWRT system. Now when I start a kernel trace 
>> then the lttng tool returns the error "LTTng transport relay-metadata 
>> not found /
>> Error: Opening metadata failed". Does anybody know what might cause 
>> this error, or have a hint on what to check?
>>
>>
>>
>> I have attached the captured output of ‘lttng-sessiond -vvv 
>> --verbose-consumer’. Here is some more context:
>>
>> ·         MIPS platform running Linux 3.18.29
>>
>> ·         Package versions:
>>
>> o   lttng-modules-2.10.4
>>
>> o   lttng-tools-2.10.1
>>
>> o   lttng-ust-2.10.0
>>
>> ·         lsmod shows that the following modules have been loaded:
>>
>> o   lttng_clock
>>
>> o   lttng_lib_ring_buffer
>>
>> o   lttng_ring_buffer_client_discard
>>
>> o   lttng_statedump
>>
>> o   lttng_tracer
>>
>> ·         Commands to create and start a session:
>>
>> o   lttng create
>>
>> o   lttng enable-event --kernel --syscall open,close
>>
>> o   lttng start
>>
>>
>>
>> When ‘lttng start’ is called then lttng-sessiond’s debug output shows 
>> “Closing metadata fd -1 (in trace_kernel_destroy_metadata() at 
>> trace-kernel.c:569)” followed by “Sending response (size: 20, retcode:
>> Opening metadata failed (45)) (in thread_manage_clients() at main.c:4641)”.
>> I assume that the error that I’m seeing is because for some reason 
>> metadata fd is being closed.
>>
>>
>>
>> Does anybody know what may cause this issue, or have a hint on to check?
>>
>>
>>
>> Kind regards,
>>
>> Robin
>>
>>
>>
>>
>> _______________________________________________
>> lttng-dev mailing list
>> lttng-dev at lists.lttng.org
>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>
>
>
>
> --
> Jérémie Galarneau
> EfficiOS Inc.
> http://www.efficios.com
>



--
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com