[lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[François Belias via lttng-dev]

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Hello,

When I run the command `sudo lttng list -k`, I get the following error:

```
Error: Unable to list kernel events: Kernel tracer not available.
```

I am trying to build LTTng-modules from the source. I followed the steps
from this website: [LTTng Documentation](
https://lttng.org/docs/v2.13/#doc-building-from-source), but I still
encounter this error. Can someone help me resolve this issue?

Thanks.

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Re: [lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[Kienan Stewart via lttng-dev]

Hi François,

On 7/12/24 2:53 PM, François Belias via lttng-dev wrote:
> Hello,
> 
> When I run the command `sudo lttng list -k`, I get the following error:

To check a few things:

   * Is lttng-sessiond being run by the root user?
   * If you run lttng-session with the "-vvv" option, are there messages 
related to loading the kernel modules?
   * Once the lttng-sessiond is started, you can check to see if the 
kernel modules have been loaded by running the following command:

```
lsmod | grep lttng
```

thanks,
kienan

> 
> ```
> Error: Unable to list kernel events: Kernel tracer not available.
> ```
> 
> I am trying to build LTTng-modules from the source. I followed the steps 
> from this website: [LTTng 
> Documentation](https://lttng.org/docs/v2.13/#doc-building-from-source 
> <https://lttng.org/docs/v2.13/#doc-building-from-source>), but I still 
> encounter this error. Can someone help me resolve this issue?
> 
> Thanks.
> 
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
_______________________________________________
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Re: [lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[François Belias via lttng-dev]

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Hi Kienan,
Yes, `lttng-sessiond` is being run by the root user. I have shared a
screenshot of the result when I ran the `lttng-sessiond -vvv` command, but
I don't think the kernel modules are loaded.
thanks


Le ven. 12 juill. 2024, à 15 h 24, Kienan Stewart <kstewart@efficios.com> a
écrit :

> Hi François,
>
> On 7/12/24 2:53 PM, François Belias via lttng-dev wrote:
> > Hello,
> >
> > When I run the command `sudo lttng list -k`, I get the following error:
>
> To check a few things:
>
>    * Is lttng-sessiond being run by the root user?
>    * If you run lttng-session with the "-vvv" option, are there messages
> related to loading the kernel modules?
>    * Once the lttng-sessiond is started, you can check to see if the
> kernel modules have been loaded by running the following command:
>
> ```
> lsmod | grep lttng
> ```
>
> thanks,
> kienan
>
> >
> > ```
> > Error: Unable to list kernel events: Kernel tracer not available.
> > ```
> >
> > I am trying to build LTTng-modules from the source. I followed the steps
> > from this website: [LTTng
> > Documentation](https://lttng.org/docs/v2.13/#doc-building-from-source
> > <https://lttng.org/docs/v2.13/#doc-building-from-source>), but I still
> > encounter this error. Can someone help me resolve this issue?
> >
> > Thanks.
> >
> > _______________________________________________
> > lttng-dev mailing list
> > lttng-dev@lists.lttng.org
> > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>

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Re: [lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[François Belias via lttng-dev]

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sorry I forgot the last part of your previous email. This is the result of
the command lsmod | grep lttng.

Le ven. 12 juill. 2024, à 15 h 52, François Belias <beliasossim@gmail.com>
a écrit :

> Hi Kienan,
> Yes, `lttng-sessiond` is being run by the root user. I have shared a
> screenshot of the result when I ran the `lttng-sessiond -vvv` command, but
> I don't think the kernel modules are loaded.
> thanks
>
>
> Le ven. 12 juill. 2024, à 15 h 24, Kienan Stewart <kstewart@efficios.com>
> a écrit :
>
>> Hi François,
>>
>> On 7/12/24 2:53 PM, François Belias via lttng-dev wrote:
>> > Hello,
>> >
>> > When I run the command `sudo lttng list -k`, I get the following error:
>>
>> To check a few things:
>>
>>    * Is lttng-sessiond being run by the root user?
>>    * If you run lttng-session with the "-vvv" option, are there messages
>> related to loading the kernel modules?
>>    * Once the lttng-sessiond is started, you can check to see if the
>> kernel modules have been loaded by running the following command:
>>
>> ```
>> lsmod | grep lttng
>> ```
>>
>> thanks,
>> kienan
>>
>> >
>> > ```
>> > Error: Unable to list kernel events: Kernel tracer not available.
>> > ```
>> >
>> > I am trying to build LTTng-modules from the source. I followed the
>> steps
>> > from this website: [LTTng
>> > Documentation](https://lttng.org/docs/v2.13/#doc-building-from-source
>> > <https://lttng.org/docs/v2.13/#doc-building-from-source>), but I still
>> > encounter this error. Can someone help me resolve this issue?
>> >
>> > Thanks.
>> >
>> > _______________________________________________
>> > lttng-dev mailing list
>> > lttng-dev@lists.lttng.org
>> > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>
>

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Re: [lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[Kienan Stewart via lttng-dev]

Hi François,

On 7/12/24 3:52 PM, François Belias wrote:
> Hi Kienan,
> Yes, `lttng-sessiond` is being run by the root user. I have shared a 
> screenshot of the result when I ran the `lttng-sessiond -vvv` command, 
> but I don't think the kernel modules are loaded.
> thanks
> 
> 

There are two issues in the screenshot you attached:

   1. You are not starting lttng-sessiond as the root user, you are 
running it as the user 'philippe'
   2. The error in the screenshot indicates that there is already 
another lttng-sessiond running.

Could you please stop all of the lttng-sessionds, then run 
`lttng-sessiond -vvv` as the root user?

thanks,
kienan

> Le ven. 12 juill. 2024, à 15 h 24, Kienan Stewart <kstewart@efficios.com 
> <mailto:kstewart@efficios.com>> a écrit :
> 
>     Hi François,
> 
>     On 7/12/24 2:53 PM, François Belias via lttng-dev wrote:
>      > Hello,
>      >
>      > When I run the command `sudo lttng list -k`, I get the following
>     error:
> 
>     To check a few things:
> 
>         * Is lttng-sessiond being run by the root user?
>         * If you run lttng-session with the "-vvv" option, are there
>     messages
>     related to loading the kernel modules?
>         * Once the lttng-sessiond is started, you can check to see if the
>     kernel modules have been loaded by running the following command:
> 
>     ```
>     lsmod | grep lttng
>     ```
> 
>     thanks,
>     kienan
> 
>      >
>      > ```
>      > Error: Unable to list kernel events: Kernel tracer not available.
>      > ```
>      >
>      > I am trying to build LTTng-modules from the source. I followed
>     the steps
>      > from this website: [LTTng
>      >
>     Documentation](https://lttng.org/docs/v2.13/#doc-building-from-source <https://lttng.org/docs/v2.13/#doc-building-from-source>
>      > <https://lttng.org/docs/v2.13/#doc-building-from-source
>     <https://lttng.org/docs/v2.13/#doc-building-from-source>>), but I still
>      > encounter this error. Can someone help me resolve this issue?
>      >
>      > Thanks.
>      >
>      > _______________________________________________
>      > lttng-dev mailing list
>      > lttng-dev@lists.lttng.org <mailto:lttng-dev@lists.lttng.org>
>      > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>     <https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev>
> 
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Re: [lttng-dev] Error: Unable to list kernel events: Kernel tracer not available

[François Belias via lttng-dev]

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Hi Kienan,
 like you asked i stopped all the lttng-sessionds. I did ps aux | grep
lttng-sessiond to locate the processes and sudo kill to terminate them.
When I ran sudo lttng-sessiond I got this error and this warning

Warning: No kernel tracer available

Le ven. 12 juill. 2024, à 16 h 01, Kienan Stewart <kstewart@efficios.com> a
écrit :

> Hi François,
>
> On 7/12/24 3:52 PM, François Belias wrote:
> > Hi Kienan,
> > Yes, `lttng-sessiond` is being run by the root user. I have shared a
> > screenshot of the result when I ran the `lttng-sessiond -vvv` command,
> > but I don't think the kernel modules are loaded.
> > thanks
> >
> >
>
> There are two issues in the screenshot you attached:
>
>    1. You are not starting lttng-sessiond as the root user, you are
> running it as the user 'philippe'
>    2. The error in the screenshot indicates that there is already
> another lttng-sessiond running.
>
> Could you please stop all of the lttng-sessionds, then run
> `lttng-sessiond -vvv` as the root user?
>
> thanks,
> kienan
>
> > Le ven. 12 juill. 2024, à 15 h 24, Kienan Stewart <kstewart@efficios.com
> > <mailto:kstewart@efficios.com>> a écrit :
> >
> >     Hi François,
> >
> >     On 7/12/24 2:53 PM, François Belias via lttng-dev wrote:
> >      > Hello,
> >      >
> >      > When I run the command `sudo lttng list -k`, I get the following
> >     error:
> >
> >     To check a few things:
> >
> >         * Is lttng-sessiond being run by the root user?
> >         * If you run lttng-session with the "-vvv" option, are there
> >     messages
> >     related to loading the kernel modules?
> >         * Once the lttng-sessiond is started, you can check to see if the
> >     kernel modules have been loaded by running the following command:
> >
> >     ```
> >     lsmod | grep lttng
> >     ```
> >
> >     thanks,
> >     kienan
> >
> >      >
> >      > ```
> >      > Error: Unable to list kernel events: Kernel tracer not available.
> >      > ```
> >      >
> >      > I am trying to build LTTng-modules from the source. I followed
> >     the steps
> >      > from this website: [LTTng
> >      >
> >     Documentation](
> https://lttng.org/docs/v2.13/#doc-building-from-source <
> https://lttng.org/docs/v2.13/#doc-building-from-source>
> >      > <https://lttng.org/docs/v2.13/#doc-building-from-source
> >     <https://lttng.org/docs/v2.13/#doc-building-from-source>>), but I
> still
> >      > encounter this error. Can someone help me resolve this issue?
> >      >
> >      > Thanks.
> >      >
> >      > _______________________________________________
> >      > lttng-dev mailing list
> >      > lttng-dev@lists.lttng.org <mailto:lttng-dev@lists.lttng.org>
> >      > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >     <https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev>
> >
>

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