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Wireshark-dev: Re: [Wireshark-dev] ThreadSanitizer issue in RecentFileStatus()

From: Jaap Keuter <jaap.keuter@xxxxxxxxx>
Date: Fri, 2 Feb 2018 17:08:40 +0100
Hi,

Good question.
Just spitballing here, in what thread are the constructors running?
RecentFileStatus::filename_ is being set during construction, but is run() already called from the other thread?

Jaap


> On 2 Feb 2018, at 15:04, Stig Bjørlykke <stig@xxxxxxxxxxxxx> wrote:
> 
> When running with ThreadSanitizer I constantly get this race condition
> report from a QString in RecentFileStatus.  Anyone else seen this?  I
> can't figure out the issue...
> 
> ==================
> WARNING: ThreadSanitizer: data race (pid=41949)
>  Read of size 8 at 0x7b0c000c0dd0 by thread T18:
>  * #0 QString::QString(QString const&) qstring.h:906
> (Wireshark:x86_64+0x100039756)
>    #1 QString::QString(QString const&) qstring.h:907
> (Wireshark:x86_64+0x100038998)
>    #2 RecentFileStatus::run() recent_file_status.cpp:33
> (Wireshark:x86_64+0x1004ffbec)
>    #3 non-virtual thunk to RecentFileStatus::run()
> recent_file_status.cpp (Wireshark:x86_64+0x1004ffd2c)
>    #4 <null> <null>:8575680 (QtCore:x86_64+0x27b6d)
> 
>  Previous write of size 8 at 0x7b0c000c0dd0 by main thread:
>  * #0 QString::QString(QString const&) qstring.h:906
> (Wireshark:x86_64+0x10003976d)
>    #1 QString::QString(QString const&) qstring.h:907
> (Wireshark:x86_64+0x100038998)
>    #2 RecentFileStatus::RecentFileStatus(QString, QObject*)
> recent_file_status.cpp:13 (Wireshark:x86_64+0x1004ff8b3)
>    #3 RecentFileStatus::RecentFileStatus(QString, QObject*)
> recent_file_status.cpp:14 (Wireshark:x86_64+0x1004ffac0)
>    #4 WiresharkApplication::refreshRecentCaptures()
> wireshark_application.cpp:256 (Wireshark:x86_64+0x10079a3b6)
>    #5 WiresharkApplication::qt_static_metacall(QObject*,
> QMetaObject::Call, int, void**)
> moc_wireshark_application_Debug.cpp:234 (Wireshark:x86_64+0x1000bbceb)
>    #6 QMetaObject::activate(QObject*, int, int, void**)
> <null>:8575680 (QtCore:x86_64+0x2194ba)
>    #7 main wireshark-qt.cpp:852 (Wireshark:x86_64+0x100037b0c)
> 
>  Issue is caused by frames marked with "*".
> 
>  Location is heap block of size 48 at 0x7b0c000c0db0 allocated by main thread:
>    #0 operator new(unsigned long) <null>:8575712
> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x6ba8e)
>    #1 WiresharkApplication::refreshRecentCaptures()
> wireshark_application.cpp:256 (Wireshark:x86_64+0x10079a36a)
>    #2 WiresharkApplication::qt_static_metacall(QObject*,
> QMetaObject::Call, int, void**)
> moc_wireshark_application_Debug.cpp:234 (Wireshark:x86_64+0x1000bbceb)
>    #3 QMetaObject::activate(QObject*, int, int, void**)
> <null>:8575712 (QtCore:x86_64+0x2194ba)
>    #4 main wireshark-qt.cpp:852 (Wireshark:x86_64+0x100037b0c)
> 
>  Thread T18 (tid=17501933, running) created by main thread at:
>    #0 pthread_create <null>:8575760
> (libclang_rt.tsan_osx_dynamic.dylib:x86_64h+0x2a34d)
>    #1 QThread::start(QThread::Priority) <null>:8575760 (QtCore:x86_64+0x2b5cb)
>    #2 main wireshark-qt.cpp:667 (Wireshark:x86_64+0x100036bcd)
> 
> SUMMARY: ThreadSanitizer: data race qstring.h:906 in
> QString::QString(QString const&)
> ==================
> 
> 
> -- 
> Stig Bjørlykke