Threadsanitizer Detection on GM

Hongxu Chen <[email protected]> Wed, 6 Feb 2019 00:43:49 +0800
Newsgroups gmane.comp.video.graphicsmagick.bugs
Message-ID <CAJPBKOGueo_N=VhudRMJH5jJEOsEHJxX+03TWpaQx71WZE_cQw@mail.gmail.com>
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Hi,

    It is known that threadsanitizer has many false positives when
detecting concurrent bugs with projects that depend on openmp, and GM is
one of them. But I saw this commit (https://reviews.llvm.org/D13072), and
it seems to solve the problem.
    There is also a blog post about this
https://xrunhprof.wordpress.com/2018/08/27/tsan-with-openmp.  So I followed
the advice; and I built openmp with -DLIBOMP_TSAN_SUPPORT=TRUE and GM with
threadsanitizer and by running "gm convert", I can see some data races
reported. My question is:
    1. Can I rely on this result and think there are some data races?
    2. Or can I even build openmp with -DLIBOMP_TSAN_SUPPORT=TRUE and
threadsanitizer
as well?

Best Regards,
Hongxu

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div>Hi,</div><div><br><=
/div><div>=C2=A0 =C2=A0 It is known that threadsanitizer has many false pos=
itives when detecting concurrent bugs with projects that depend on openmp, =
and GM is one of=C2=A0them. But I saw this commit (<a href=3D"https://revie=
ws.llvm.org/D13072">https://reviews.llvm.org/D13072</a>), and it seems to s=
olve the problem.</div><div>=C2=A0 =C2=A0 There is also a blog post about t=
his=C2=A0<a href=3D"https://xrunhprof.wordpress.com/2018/08/27/tsan-with-op=
enmp">https://xrunhprof.wordpress.com/2018/08/27/tsan-with-openmp</a>.=C2=
=A0 So I followed the advice; and I built openmp with=C2=A0<span style=3D"f=
ont-size:13px;color:rgb(0,0,0);font-family:&quot;Segoe UI&quot;,&quot;Segoe=
 UI Emoji&quot;,&quot;Segoe UI Symbol&quot;,Lato,&quot;Helvetica Neue&quot;=
,Helvetica,Arial,sans-serif">-DLIBOMP_TSAN_SUPPORT=3DTRUE and GM with threa=
dsanitizer and by running &quot;gm convert&quot;, I can see some data races=
 reported. My question is:</span></div><div><span style=3D"color:rgb(0,0,0)=
;font-family:&quot;Segoe UI&quot;,&quot;Segoe UI Emoji&quot;,&quot;Segoe UI=
 Symbol&quot;,Lato,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif;fo=
nt-size:13px">=C2=A0 =C2=A0 1. Can I rely on this result and think there ar=
e some data races?</span></div><div><span style=3D"color:rgb(0,0,0);font-fa=
mily:&quot;Segoe UI&quot;,&quot;Segoe UI Emoji&quot;,&quot;Segoe UI Symbol&=
quot;,Lato,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif;font-size:=
13px">=C2=A0 =C2=A0 2. Or can I even build openmp with=C2=A0</span><span st=
yle=3D"color:rgb(0,0,0);font-family:&quot;Segoe UI&quot;,&quot;Segoe UI Emo=
ji&quot;,&quot;Segoe UI Symbol&quot;,Lato,&quot;Helvetica Neue&quot;,Helvet=
ica,Arial,sans-serif;font-size:13px">-DLIBOMP_TSAN_SUPPORT=3DTRUE and</span=
><span style=3D"color:rgb(0,0,0);font-family:&quot;Segoe UI&quot;,&quot;Seg=
oe UI Emoji&quot;,&quot;Segoe UI Symbol&quot;,Lato,&quot;Helvetica Neue&quo=
t;,Helvetica,Arial,sans-serif;font-size:13px">=C2=A0threadsanitizer as well=
?</span></div><br clear=3D"all"><div><div dir=3D"ltr" class=3D"gmail_signat=
ure"><div dir=3D"ltr"><div><div dir=3D"ltr"><font color=3D"#313131" face=3D=
"Arial, sans-serif"><span style=3D"font-size:12px">Best Regards,</span></fo=
nt><div><font color=3D"#313131" face=3D"Arial, sans-serif"><span style=3D"f=
ont-size:12px">Hongxu</span></font></div></div></div></div></div></div></di=
v></div></div>

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