Bug 383820

Summary: plasma-discover dies at start in a thread with most calls to QQmlTypeLoader
Product: [Applications] Discover Reporter: rmbldr
Component: discoverAssignee: Aleix Pol <aleixpol>
Status: RESOLVED NOT A BUG    
Severity: crash Keywords: drkonqi
Priority: NOR    
Version First Reported In: 5.10.4   
Target Milestone: ---   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description rmbldr 2017-08-21 20:08:16 UTC 
Application: plasma-discover (5.10.4)

Qt Version: 5.9.1
Frameworks Version: 5.37.0
Operating System: Linux 4.10.0-32-generic x86_64
Distribution: KDE neon User Edition 5.10

-- Information about the crash:
- What I was doing when the application crashed:
Started plasma-discover from the command line (kdesudo is having problems, too. plasma-discove core dumps immediately, both starting with sudo from a user account and starting from root.

The crash can be reproduced every time.

-- Backtrace:
Application: Discover (plasma-discover), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
[Current thread is 1 (Thread 0x7fa7d90308c0 (LWP 9935))]

Thread 4 (Thread 0x7fa7c6a59700 (LWP 9939)):
[KCrash Handler]
#6  0x00007fa7d645101b in QString::QString (other=..., this=0x7fa7c6a56c50) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qstring.h:906
#7  QV4::Compiler::StringTableGenerator::stringForIndex (index=268435456, this=<optimized out>) at ../../include/QtQml/5.9.1/QtQml/private/../../../../../src/qml/compiler/qv4compiler_p.h:77
#8  QV4::Compiler::JSUnitGenerator::stringForIndex (index=268435456, this=<optimized out>) at ../../include/QtQml/5.9.1/QtQml/private/../../../../../src/qml/compiler/qv4compiler_p.h:97
#9  QmlIR::Document::stringAt (index=268435456, this=<optimized out>) at compiler/qqmlirbuilder_p.h:442
#10 QmlIR::IRLoader::loadObject (this=this@entry=0x7fa7c6a56cf0, serializedObject=<optimized out>) at compiler/qqmlirbuilder.cpp:2144
#11 0x00007fa7d6452ccf in QmlIR::IRLoader::load (this=this@entry=0x7fa7c6a56cf0) at compiler/qqmlirbuilder.cpp:2092
#12 0x00007fa7d65c4978 in QQmlTypeData::restoreIR (this=this@entry=0x7fa7bc0b2300, unit=...) at qml/qqmltypeloader.cpp:2443
#13 0x00007fa7d65c4dbc in QQmlTypeData::tryLoadFromDiskCache (this=0x7fa7bc0b2300) at qml/qqmltypeloader.cpp:2087
#14 0x00007fa7d65c66f2 in QQmlTypeData::dataReceived (this=0x7fa7bc0b2300, data=...) at qml/qqmltypeloader.cpp:2384
#15 0x00007fa7d65bd868 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc0b2300, d=...) at qml/qqmltypeloader.cpp:1269
#16 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc0b2300, fileName=...) at qml/qqmltypeloader.cpp:1259
#17 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc0b2300) at qml/qqmltypeloader.cpp:1134
#18 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc0b2300, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#19 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc0b2300, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#20 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc0b2300, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#21 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#22 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x7fa7bc095360) at qml/qqmltypeloader.cpp:2641
#23 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x7fa7bc095360) at qml/qqmltypeloader.cpp:2521
#24 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc095360, d=...) at qml/qqmltypeloader.cpp:1272
#25 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc095360, fileName=...) at qml/qqmltypeloader.cpp:1259
#26 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc095360) at qml/qqmltypeloader.cpp:1134
#27 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc095360, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#28 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc095360, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#29 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc095360, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#30 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#31 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x7fa7bc088120) at qml/qqmltypeloader.cpp:2641
#32 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x7fa7bc088120) at qml/qqmltypeloader.cpp:2521
#33 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc088120, d=...) at qml/qqmltypeloader.cpp:1272
#34 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc088120, fileName=...) at qml/qqmltypeloader.cpp:1259
#35 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc088120) at qml/qqmltypeloader.cpp:1134
#36 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc088120, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#37 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc088120, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#38 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc088120, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#39 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#40 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x7fa7bc079ea0) at qml/qqmltypeloader.cpp:2641
#41 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x7fa7bc079ea0) at qml/qqmltypeloader.cpp:2521
#42 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc079ea0, d=...) at qml/qqmltypeloader.cpp:1272
#43 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc079ea0, fileName=...) at qml/qqmltypeloader.cpp:1259
#44 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc079ea0) at qml/qqmltypeloader.cpp:1134
#45 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc079ea0, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#46 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc079ea0, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#47 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc079ea0, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#48 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#49 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x7fa7bc063d70) at qml/qqmltypeloader.cpp:2641
#50 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x7fa7bc063d70) at qml/qqmltypeloader.cpp:2521
#51 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc063d70, d=...) at qml/qqmltypeloader.cpp:1272
#52 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc063d70, fileName=...) at qml/qqmltypeloader.cpp:1259
#53 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc063d70) at qml/qqmltypeloader.cpp:1134
#54 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc063d70, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#55 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc063d70, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#56 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc063d70, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#57 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#58 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x7fa7bc0596c0) at qml/qqmltypeloader.cpp:2641
#59 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x7fa7bc0596c0) at qml/qqmltypeloader.cpp:2521
#60 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc0596c0, d=...) at qml/qqmltypeloader.cpp:1272
#61 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x7fa7bc0596c0, fileName=...) at qml/qqmltypeloader.cpp:1259
#62 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=this@entry=0x189cd08, blob=blob@entry=0x7fa7bc0596c0) at qml/qqmltypeloader.cpp:1134
#63 0x00007fa7d65ccf04 in PlainLoader::loadThread (this=<optimized out>, blob=0x7fa7bc0596c0, loader=0x189cd08) at qml/qqmltypeloader.cpp:979
#64 QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x7fa7bc0596c0, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1038
#65 0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x7fa7bc0596c0, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#66 QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=mode@entry=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#67 0x00007fa7d65c27b9 in QQmlTypeData::resolveTypes (this=this@entry=0x18ef3e0) at qml/qqmltypeloader.cpp:2641
#68 0x00007fa7d65c2c52 in QQmlTypeData::allDependenciesDone (this=0x18ef3e0) at qml/qqmltypeloader.cpp:2521
#69 0x00007fa7d65bd8ed in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=blob@entry=0x18ef3e0, d=...) at qml/qqmltypeloader.cpp:1272
#70 0x00007fa7d65be1b8 in QQmlTypeLoader::setData (this=this@entry=0x189cd08, blob=0x18ef3e0, fileName=...) at qml/qqmltypeloader.cpp:1259
#71 0x00007fa7d65bf39a in QQmlTypeLoader::loadThread (this=0x189cd08, blob=blob@entry=0x18ef3e0) at qml/qqmltypeloader.cpp:1134
#72 0x00007fa7d65bf41d in QQmlTypeLoaderThread::loadThread (this=<optimized out>, b=0x18ef3e0) at qml/qqmltypeloader.cpp:875
#73 0x00007fa7d662b408 in QQmlThreadPrivate::threadEvent (this=0x189c630) at qml/ftw/qqmlthread.cpp:196
#74 0x00007fa7d662ba7a in QQmlThreadPrivate::event (this=0x189c630, e=0x18f1b80) at qml/ftw/qqmlthread.cpp:134
#75 0x00007fa7d6dfd3fc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#76 0x00007fa7d6e04e07 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#77 0x00007fa7d5df5798 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#78 0x00007fa7d5df7f7b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#79 0x00007fa7d5e4b323 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#80 0x00007fa7d0735197 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#81 0x00007fa7d07353f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#82 0x00007fa7d073549c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#83 0x00007fa7d5e4a94b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#84 0x00007fa7d5df37ca in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#85 0x00007fa7d5c1ccd4 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#86 0x00007fa7d662b0c5 in QQmlThreadPrivate::run (this=0x189c630) at qml/ftw/qqmlthread.cpp:147
#87 0x00007fa7d5c21989 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#88 0x00007fa7d262a6ba in start_thread (arg=0x7fa7c6a59700) at pthread_create.c:333
#89 0x00007fa7d52123dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7fa7c725a700 (LWP 9937)):
#0  0x00007fa7d520224d in read () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fa7d07786f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fa7d0734e74 in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fa7d0735330 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fa7d073549c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fa7d5e4a94b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fa7d5df37ca in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fa7d5c1ccd4 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fa7d9170b75 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#9  0x00007fa7d5c21989 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fa7d262a6ba in start_thread (arg=0x7fa7c725a700) at pthread_create.c:333
#11 0x00007fa7d52123dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7fa7c82a2700 (LWP 9936)):
#0  0x00007fa7d520670d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fa7d04ccc62 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fa7d04ce8d7 in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fa7cb6c6329 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007fa7d5c21989 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fa7d262a6ba in start_thread (arg=0x7fa7c82a2700) at pthread_create.c:333
#6  0x00007fa7d52123dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fa7d90308c0 (LWP 9935)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fa7d5c228eb in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fa7d662b733 in QQmlThreadPrivate::wait (this=<optimized out>) at qml/ftw/qqmlthread.cpp:62
#3  QQmlThread::internalCallMethodInThread (this=0x189c700, message=<optimized out>) at qml/ftw/qqmlthread.cpp:327
#4  0x00007fa7d65b89a5 in QQmlThread::callMethodInThread<QQmlDataBlob*, QQmlDataBlob*, QQmlTypeLoaderThread> (arg=<synthetic pointer>, Member=<optimized out>, this=<optimized out>) at ../../include/QtQml/5.9.1/QtQml/private/../../../../../src/qml/qml/ftw/qqmlthread_p.h:165
#5  QQmlTypeLoaderThread::load (this=<optimized out>, b=<optimized out>) at qml/qqmltypeloader.cpp:812
#6  0x00007fa7d65cce91 in PlainLoader::load (this=<optimized out>, loader=0x189cd08, blob=0x18ef3e0) at qml/qqmltypeloader.cpp:983
#7  QQmlTypeLoader::doLoad<PlainLoader> (this=0x189cd08, loader=..., blob=0x18ef3e0, mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1047
#8  0x00007fa7d65c0e49 in QQmlTypeLoader::load (mode=QQmlTypeLoader::PreferSynchronous, blob=0x18ef3e0, this=0x189cd08) at qml/qqmltypeloader.cpp:1070
#9  QQmlTypeLoader::getType (this=0x189cd08, url=..., mode=QQmlTypeLoader::PreferSynchronous) at qml/qqmltypeloader.cpp:1647
#10 0x00007fa7d65a1f49 in QQmlComponentPrivate::loadUrl (this=0x18ef120, newUrl=..., mode=mode@entry=QQmlComponent::PreferSynchronous) at qml/qqmlcomponent.cpp:660
#11 0x00007fa7d65a22bb in QQmlComponent::loadUrl (this=this@entry=0x18f0f10, url=...) at qml/qqmlcomponent.cpp:617
#12 0x00007fa7d6618253 in QQmlApplicationEnginePrivate::startLoad (this=0x189cbb0, url=..., data=..., dataFlag=dataFlag@entry=false) at qml/qqmlapplicationengine.cpp:115
#13 0x00007fa7d66182ad in QQmlApplicationEngine::load (this=<optimized out>, url=...) at qml/qqmlapplicationengine.cpp:259
#14 0x00000000004122cc in ?? ()
#15 0x000000000040d16a in ?? ()
#16 0x00007fa7d512b830 in __libc_start_main (main=0x40cb40, argc=1, argv=0x7ffc90fbeb48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc90fbeb38) at ../csu/libc-start.c:291
#17 0x000000000040d719 in _start ()

Reported using DrKonqi
Comment 1 Aleix Pol 2017-09-06 15:30:13 UTC 
You shouldn't run Discover with sudo (or as root for that matter).

The backend will take care of the privilege escalation if it's necessary.