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Hi Jonathan,</div>
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<br>
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After having written '<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important">sudo
systemctl stop lttng-sessiond.service', the command '<span style="background-color:rgb(255, 255, 255);display:inline !important">sudo lttng-sessiond -vvv > /tmp/lttng-sessiond.log 2>&1' gives me nothing.</span><br>
<span style="background-color:rgb(255, 255, 255);display:inline !important"><b><br>
</b></span></span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><span style="background-color:rgb(255, 255, 255);display:inline !important"><b>ls
-la /var/run/lttng/ : </b></span></span><a href="https://paste.ubuntu.com/p/gjbqKkCrZK/" id="LPlnk587030" style="font-family: Calibri, Helvetica, sans-serif, EmojiFont, "Apple Color Emoji", "Segoe UI Emoji", NotoColorEmoji, "Segoe UI Symbol", "Android Emoji", EmojiSymbols; font-size: 12pt;">Ubuntu
Pastebin</a></div>
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<b>groups</b> : <a href="https://paste.ubuntu.com/p/pjVFHk7kFZ/" id="LPlnk488565">Ubuntu Pastebin</a><br>
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><b>lttng-sessiond
-vvv > /tmp/lttng-sessiond-local.log 2>&1 :</b> nothing</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color: rgb(32, 31, 30); font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px;"><b>/tmp/lttng-sessiond-local.log
</b>: </span><a href="https://paste.ubuntu.com/p/bj38FhhVpc/" id="LPlnk513333" style="font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; font-size: 14.6667px;">Ubuntu
Pastebin</a></div>
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<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
The issue persist with the '<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important">lttng
list' command.</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important">Best
regards,</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><br>
</span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><b>Sorry
it was indeed : </b></span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><span style="background-color:rgb(255, 255, 255);display:inline !important">The
command lines entered to compile are quite the same, I just had to modify :</span><br style="background-color:rgb(255, 255, 255)">
<span style="background-color:rgb(255, 255, 255);display:inline !important">> this : gcc -o hello hello.o hello-tp.o <span style="background-color:rgb(255, 255, 255);display:inline !important">-llttng-ust -ldl</span></span><br style="background-color:rgb(255, 255, 255)">
<span style="background-color:rgb(255, 255, 255);display:inline !important">> to this : gcc -o hello hello.o hello-tp.o
<b>-L/usr/local/lib</b> -llttng-ust -ldl</span></span></div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<span style="color:rgb(32, 31, 30);font-family:"Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif;font-size:14.6667px;background-color:rgb(255, 255, 255);display:inline !important"><span style="background-color:rgb(255, 255, 255);display:inline !important">(I
just wanted to focus the importance of <span style="background-color:rgb(255, 255, 255);display:inline !important"><span> </span></span><b>-L/usr/local/lib)</b></span></span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>De :</b> Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com><br>
<b>Envoyé :</b> mercredi 24 mars 2021 16:32<br>
<b>À :</b> MONTET Julien <julien.montet@reseau.eseo.fr><br>
<b>Cc :</b> lttng-dev <lttng-dev@lists.lttng.org><br>
<b>Objet :</b> Re: [lttng-dev] Issues on basic LTTng trace userspace (tutorial)</font>
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<div class="PlainText">Hi Julien,<br>
<br>
Please always keep the mailing list in CC.<br>
<br>
> I am running 'lttng list --userspace' with the application running in another terminal (like the tutorial, and also with a while that loop on tracepoint(...).<br>
<br>
ok.<br>
<br>
> <br>
> You can find here the Ubuntu paste : Ubuntu Pastebin<<a href="https://paste.ubuntu.com/p/bWw25kmSTq/">https://paste.ubuntu.com/p/bWw25kmSTq/</a>><br>
<br>
Based on this, it seems like lttng-ust is unable to find the socket for a sessiond either<br>
locally (for your user) [1] or a global one (root lttng-sessiond) [2].<br>
<br>
[1] 43: libust[207688/207690]: Info: sessiond not accepting connections to local apps socket (in ust_listener_thread() at lttng-ust-comm.c:1822)<br>
[2] 45: libust[207688/207689]: Info: sessiond not accepting connections to global apps socket (in ust_listener_thread() at lttng-ust-comm.c:1822)<br>
<br>
Since you installed via the PPA, a systemd service control service is installed<br>
that control a global (root) lttng-sessiond.<br>
<br>
First let's stop it.<br>
sudo systemctl stop lttng-sessiond.service<br>
<br>
Then in a console, again use a paste service to share the content of /tmp/lttng-sessiond.log with us<br>
<br>
sudo lttng-sessiond -vvv > /tmp/lttng-sessiond.log 2>&1<br>
<br>
In another console, while the lttng-sessiond process is running, please have a look at the /var/run/lttng directory:<br>
<br>
ls -la /var/run/lttng/<br>
<br>
Again use a paste service to share this with us.<br>
<br>
Also can you provide the output of the following while using the user you are<br>
normally using to play with lttng:<br>
<br>
groups<br>
<br>
You can also try to spawn a local lttng-sessiond for the user.<br>
Note that a global and many local lttng-sessiond can coexist but for the sake of debugging<br>
we will only have one of each at a time. <br>
<br>
Kill the root lttng-sessiond we started earlier and start a local one:<br>
<br>
lttng-sessiond -vvv > /tmp/lttng-sessiond-local.log 2>&1 <br>
<br>
Note the absence of `sudo` here.<br>
<br>
Again please share the content of /tmp/lttng-sessiond-local.log via a paste<br>
service.<br>
<br>
>From there you can retry your experiment with the `lttng list` command.<br>
<br>
Cheers<br>
<br>
<br>
> The command lines entered to compile are quite the same, I just had to modify :<br>
> this : gcc -o hello hello.o hello-tp.o<br>
> to this : gcc -o hello hello.o hello-tp.o -L/usr/local/lib -llttng-ust -ldl<br>
<br>
As per the doc [3]:<br>
gcc -o hello hello.o hello-tp.o -llttng-ust -ldl<br>
<br>
[3] <a href="https://lttng.org/docs/v2.12/#doc-tracing-your-own-user-application">
https://lttng.org/docs/v2.12/#doc-tracing-your-own-user-application</a> Bullet point #6<br>
<br>
Cheers<br>
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