[lttng-dev] session create failed

[Jonathan Rajotte]

AFAIK if you want to use kernel tracing as a regular user you need:
1)  to be part of a tracing user group (default: tracing [1])
2) sessiond must be started by root

you can use "sudo lttng-sessiond -d" before doing any lttng related tasks
and/or you can add sessiond to your boot sequence.

[1] you might need to create it, you can also use another group via
lttng-sessiond -g <group_name>


On Tue, Mar 18, 2014 at 12:53 PM, Lingyu Zhu <lynuszhu at gmail.com> wrote:

>
>
> On Wed, Mar 19, 2014 at 12:35 AM, Jonathan Rajotte <
> jonathan.r.julien at gmail.com> wrote:
>
>> Hi Lingyu,
>>
>>  Does a sessiond is created on boot ?
>>> You can check via htop and filter for lttng or sessiond.
>>>
>> No sessiond is created on boot before I do these operations.
>> what else info should I provide?
>>
>>
>>
>>  On Tue, Mar 18, 2014 at 12:31 PM, Lingyu Zhu <lynuszhu at gmail.com> wrote:
>>
>>>   Hello,
>>> Sorry for being away a few days. My thesis opening proposal is hiting
>>> the deadline, which happens to be same date for GSoC. Now I can be fully
>>> devoted to lttng and compose my GSoC proposal.
>>>
>>> Anyway, I may have found a bug.I'm not very sure. Here is my log:
>>>
>>> ===================================================
>>>  [lynus at slave1 ~]$lttng create
>>> Spawning a session daemon
>>> Session auto-20140319-081547 created.
>>> Traces will be written in /home/lynus/lttng-traces/auto-20140319-081547
>>> [lynus at slave1 ~]$ lttng enable-event page_block -k
>>> Error: Event page_block: Tracing the kernel requires a root
>>> lttng-sessiond daemon, as well as "tracing" group membership or root user
>>> ID for the lttng client. (channel channel0, session auto-20140319-081547)
>>> Warning: Some command(s) went wrong
>>> [lynus at slave1 ~]$ lttng destroy
>>> Session auto-20140319-081547 destroyed
>>> [lynus at slave1 ~]$ sudo su -
>>> [sudo] password for lynus:
>>> root at slave1:~# lttng create
>>> Spawning a session daemon
>>> Warning: No tracing group detected
>>> Session auto-20140319-081615 created.
>>> Traces will be written in /root/lttng-traces/auto-20140319-081615
>>> PERROR [4774/4882]: bind inet: Address already in use (in
>>> lttcomm_bind_inet_sock() at inet.c:109)
>>> Warning: An other session daemon is using this JUL port. JUL support
>>> will be deactivated not interfering with the tracing.
>>> root at slave1:~# lttng create
>>> Session auto-20140319-081620 created.
>>> Traces will be written in /root/lttng-traces/auto-20140319-081620
>>> root at slave1:~#
>>> [END] 2014/3/19 0:04:31
>>> ======================================================
>>>
>>> These command is issued right after my machine is booted. And it failed
>>> every time if I try to enable kernel event as non-root user first then
>>> switch to root to create session.  If I directly switch to root and create
>>> a seesion, everything is normal. So I guess I may have come across a bug.
>>> Any comment?
>>>
>>> _______________________________________________
>>> lttng-dev mailing list
>>> lttng-dev at lists.lttng.org
>>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>>
>>>
>>
>>
>> --
>> Jonathan Rajotte Julien
>> Chargé de laboratoire, INF1995
>> Polytechnique Montréal
>>
>
>


-- 
Jonathan Rajotte Julien
Chargé de laboratoire, INF1995
Polytechnique Montréal
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