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<p>Hi Majid,</p>
<p><br>
</p>
<p>See the documentation here:
<a class="moz-txt-link-freetext" href="http://lttng.org/docs/v2.10/#doc-using-lttng-ust-with-daemons">http://lttng.org/docs/v2.10/#doc-using-lttng-ust-with-daemons</a> and
<a class="moz-txt-link-freetext" href="http://lttng.org/docs/v2.10/#doc-liblttng-ust-fd">http://lttng.org/docs/v2.10/#doc-liblttng-ust-fd</a>. Firefox requires
at least one of those extra libraries to be preloaded, the one for
fork I think. <br>
</p>
<p><br>
</p>
<p>I recall trying to trace firefox with lttng-cyg-profile without
much success. Without the liblttng-ust-fork.so preloaded, my tabs
had segfaults. But when I tried with both libraries, it seemed
there was a conflict between cyg-profile and the other preloaded
libraries, I don't remember exactly what happened. Maybe you won't
have this problem with lttng-ust-libc-wrapper.<br>
</p>
<p><br>
</p>
<p>I hope this helps,</p>
<p>Geneviève<br>
</p>
<br>
<div class="moz-cite-prefix">On 2018-01-08 10:35 PM, Majid Rezazadeh
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CACbQsw8qxK=8sFZqUs_9KL_bRy+-bTY70PE3kKHEMeSyZHmjaA@mail.gmail.com">
<div dir="ltr"><span style="font-size:12.8px">Hi all</span><br>
<br>
<span style="font-size:12.8px">I am using lttng-ust-libc-wr</span><font
face="arial, helvetica, sans-serif">apper <span style="color:rgb(36,41,46);white-space:pre-wrap">for instrumenting</span> </font><span style="color:rgb(36,41,46);white-space:pre-wrap"><font face="arial, helvetica, sans-serif">some calls to libc for </font></span><font
face="arial, helvetica, sans-serif">som<span
style="font-size:12.8px">e applica</span></font><span
style="font-size:12.8px">tions like Firefox and Chrome, but I
receive "Segmentation fault (core dumped)". I compile
lttng-ust-pthread.c (gcc -fPIC -shared -o test.so
lttng-ust-pthread.c -ldl) and then I use "LD_PRELOAD=test.so
firefox" but I receive segmentation fault (I have exported
LD_LIBRARY_PATH to the absolute path of test.so file). I found
out that when I replace tracepoints with printf in
lttng_ust_pthread.c, I receive no error. It seems that hooking
tracepoints in this wrapper makes some problems. Do you have
any idea in this regard?</span><br>
<div>
<div style="font-size:12.8px"><br>
</div>
<div style="font-size:12.8px"><span style="font-size:12.8px"><font
color="#000000">Thanks<br>
<br>
</font></span></div>
</div>
<div style="font-size:12.8px"><span style="font-size:12.8px"><font
color="#000000">Majid</font></span></div>
</div>
<br>
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