[lttng-dev] Error: Unable to list kernel events: Kernel tracer not available
Jonathan Rajotte-Julien
jonathan.rajotte-julien at efficios.com
Fri Nov 30 19:05:18 EST 2018
Hi Szymon,
First thing to validate is if the modules compilation worked.
Please give us the output of the following command:
ls -la /lib/modules/`uname -r`/extra
Since you installed lttng-tools via the package repo, a service was installed
to spawn lttng-sessiond.
You can control the service using systemctl:
sudo systemctl stop lttng-sessiond.service
sudo systemctl start lttng-sessiond.service
sudo systemctl restart lttng-sessiond.service
The output you gave us indicate that a sessiond is already running (the one
started by the systemd service). Which is of no use.
A colleague suggested that since you might have installed the modules package
after the lttng-tools package, the modules were not present when lttng-sessiond
service was started thus could not have been loaded.
To test this hypothesis you can issue the following command followed by your
test.
sudo systemctl restart lttng-sessiond.service
sleep 1
sudo lttng list -k
If it doesn't work, stop the service and start a sessiond in verbose mode
manually.
sudo systemctl stop lttng-sessiond.service
sudo lttng-sessiond -vvv --verbose-consumer
This should give us more information.
You can use a service like https://paste.debian.net/ to give us any of the
output if it ends up being more than ~20 lines.
Thanks for using the mailing list instead of Stack Overflow. Once we find the
problem we can update you SO thread with the solution.
Cheers
On Sat, Dec 01, 2018 at 12:22:05AM +0100, Szymon Rąpała wrote:
> Hello,
>
> I'm new to lttng so I tried to follow the 'Quick Start' tutorial from
> lttng.org.
>
> I have installed LTTng Stable 2.10 PPA (lttng-tools, lttng-modules-dkms,
> liblttng-ust-dev). At very beginning I am facing a problem with kernel
> tracking:
>
> ~/lttng_train$ sudo lttng create my
> Session my created.
> Traces will be written in /home/szymon/lttng-traces/my-20181130-222008
> ~/lttng_train$ sudo lttng list --kernel
> Error: Unable to list kernel events: Kernel tracer not available
> Error: Command error
>
> Any ideas? Thanks for support!
>
> Additional info:
>
> ~/lttng_train$ dpkg -l | grep lttng
> ii liblttng-ctl0:amd64
> 2.10.5-1~ubuntu16.04.1 amd64 LTTng
> control and utility library
> ii liblttng-ust-ctl4:amd64
> 2.10.2-1~ubuntu16.04.1 amd64 LTTng 2.0
> Userspace Tracer (trace control library)
> ii liblttng-ust-dev:amd64
> 2.10.2-1~ubuntu16.04.1 amd64 LTTng 2.0
> Userspace Tracer (development files)
> ii liblttng-ust-python-agent0:amd64
> 2.10.2-1~ubuntu16.04.1 amd64 LTTng 2.0
> Userspace Tracer (Python agent native library)
> ii liblttng-ust0:amd64
> 2.10.2-1~ubuntu16.04.1 amd64 LTTng 2.0
> Userspace Tracer (tracing libraries)
> ii lttng-modules-dkms
> 2.10.8-1~ubuntu16.04.1 all Linux Trace
> Toolkit (LTTng) kernel modules (DKMS)
> ii lttng-tools
> 2.10.5-1~ubuntu16.04.1 amd64 LTTng
> control and utility programs
>
> ~$ uname -a
> Linux szymon 4.4.0-98-generic #121-Ubuntu SMP Tue Oct 10 14:24:03 UTC
> 2017 x86_64 x86_64 x86_64 GNU/Linux
>
> ~$ lsb_release -a
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description: Ubuntu 16.04.5 LTS
> Release: 16.04
> Codename: xenial
>
> ~/lttng_train$ ps aux | grep lttng-sessiond
> root 7862 0.0 0.3 859960 10880 ? Ssl 19:12 0:00
> /usr/bin/lttng-sessiond
> szymon 14853 0.0 0.0 15440 936 pts/1 S+ 22:21 0:00 grep
> --color=auto lttng-sessiond
>
> ~/lttng_train$ lsmod | grep lttng
> ~/
>
> ~/lttng_train$ sudo lttng-sessiond -vvv
> DEBUG1 - 00:16:41.328643679 [16578/16578]: [sessiond configuration]
> DEBUG1 - 00:16:41.328715142 [16578/16578]: verbose: 3
> DEBUG1 - 00:16:41.328723618 [16578/16578]: verbose consumer: 0
> DEBUG1 - 00:16:41.328729230 [16578/16578]: quiet mode: False
> DEBUG1 - 00:16:41.328735428 [16578/16578]: agent_tcp_port:
> [5345, 5354]
> DEBUG1 - 00:16:41.328741084 [16578/16578]: application socket timeout: 5
> DEBUG1 - 00:16:41.328761096 [16578/16578]: no-kernel: False
> DEBUG1 - 00:16:41.328776829 [16578/16578]: background: False
> DEBUG1 - 00:16:41.328788328 [16578/16578]: daemonize: False
> DEBUG1 - 00:16:41.328800092 [16578/16578]: signal parent on start: False
> DEBUG1 - 00:16:41.328812153 [16578/16578]: tracing group name:
> tracing
> DEBUG1 - 00:16:41.328823395 [16578/16578]: kmod_probe_list: None
> DEBUG1 - 00:16:41.328834022 [16578/16578]: kmod_extra_probe_list: None
> DEBUG1 - 00:16:41.328848328 [16578/16578]: rundir:
> /var/run/lttng
> DEBUG1 - 00:16:41.328857048 [16578/16578]: application socket path:
> /var/run/lttng/lttng-ust-sock-7
> DEBUG1 - 00:16:41.328866302 [16578/16578]: client socket path:
> /var/run/lttng/client-lttng-sessiond
> DEBUG1 - 00:16:41.328881494 [16578/16578]: wait shm path:
> /lttng-ust-wait-7
> DEBUG1 - 00:16:41.328890337 [16578/16578]: health socket path:
> /var/run/lttng/sessiond-health
> DEBUG1 - 00:16:41.328896087 [16578/16578]: LTTNG_UST_CLOCK_PLUGIN: None
> DEBUG1 - 00:16:41.328902562 [16578/16578]: pid file path:
> /var/run/lttng/lttng-sessiond.pid
> DEBUG1 - 00:16:41.328909781 [16578/16578]: lock file path:
> /var/run/lttng/lttng-sessiond.lck
> DEBUG1 - 00:16:41.328916938 [16578/16578]: session load path: None
> DEBUG1 - 00:16:41.328924592 [16578/16578]: agent port file path:
> /var/run/lttng/agent.port
> DEBUG1 - 00:16:41.328936395 [16578/16578]: consumerd32 path:
> /var/run/lttng/ustconsumerd32
> DEBUG1 - 00:16:41.328947517 [16578/16578]: consumerd32 bin path:
> Unknown
> DEBUG1 - 00:16:41.328961683 [16578/16578]: consumerd32 lib dir:
> Unknown
> DEBUG1 - 00:16:41.328970009 [16578/16578]: consumerd32 err unix sock
> path:/var/run/lttng/ustconsumerd32/error
> DEBUG1 - 00:16:41.328977730 [16578/16578]: consumerd32 cmd unix sock
> path:/var/run/lttng/ustconsumerd32/command
> DEBUG1 - 00:16:41.328985023 [16578/16578]: consumerd64 path:
> /var/run/lttng/ustconsumerd64
> DEBUG1 - 00:16:41.328992714 [16578/16578]: consumerd64 bin path:
> /usr/lib/x86_64-linux-gnu/lttng/libexec/lttng-consumerd
> DEBUG1 - 00:16:41.329005793 [16578/16578]: consumerd64 lib dir:
> /usr/lib/x86_64-linux-gnu
> DEBUG1 - 00:16:41.329017089 [16578/16578]: consumerd64 err unix sock
> path:/var/run/lttng/ustconsumerd64/error
> DEBUG1 - 00:16:41.329028919 [16578/16578]: consumerd64 cmd unix sock
> path:/var/run/lttng/ustconsumerd64/command
> DEBUG1 - 00:16:41.329040967 [16578/16578]: kconsumerd path:
> /var/run/lttng/kconsumerd
> DEBUG1 - 00:16:41.329053218 [16578/16578]: kconsumerd err unix sock
> path: /var/run/lttng/kconsumerd/error
> DEBUG1 - 00:16:41.329064330 [16578/16578]: kconsumerd cmd unix sock
> path: /var/run/lttng/kconsumerd/command
> DEBUG3 - 00:16:41.329076040 [16578/16578]: Creating LTTng run
> directory: /var/run/lttng (in create_lttng_rundir() at main.c:5306)
> Error: A session daemon is already running.
> DEBUG1 - 00:16:41.329161207 [16578/16578]: Cleaning up options (in
> sessiond_cleanup_options() at main.c:648)
> DEBUG1 - 00:16:41.329178082 [16578/16578]: Destroying run_as worker
> (in run_as_destroy_worker() at runas.c:709)
>
> Regards,
>
> Simon
> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
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--
Jonathan Rajotte-Julien
EfficiOS
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