Sorry about the terrible turnaround time. This appears to be a crash in QtWebKit, while it is trying to load a plugin. Rather unlikely to be directly related to anything we are doing in RKWard.

Is this crash repeatable for you? Do other page loads (e.g. ?print) work ok for you?

Sure no problem.

Actually this occurs on one of my systems but not the other, so indeed, most likely it is not directly an RKward problem.

On the system that does crash, it now happens every time when I click on the index when in a help page. What could be the problem? The two systems I use for working with R/RKward both have the same OS (Manjaro) and are equally updated. If it is a webkit problem any pointers were to look into? Below is the trace from a test I just did.

Cheers

Application: RKWard (rkward), signal: Aborted
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f5206494640 (LWP 6265))]

Thread 7 (Thread 0x7f518bb9f700 (LWP 6282)):
#0  0x00007f51fd3ed97b in poll () at /usr/lib/libc.so.6
#1  0x00007f51f73eaff3 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f51f73eb10e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f51fe085314 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f51fe0273db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f51fde367ae in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f51fde3bb4d in  () at /usr/lib/libQt5Core.so.5
#7  0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 6 (Thread 0x7f51d0bff700 (LWP 6278)):
#0  0x00007f51f7431b94 in g_mutex_unlock () at /usr/lib/libglib-2.0.so.0
#1  0x00007f51f73eae9e in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f51f73eb10e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f51fe085314 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f51fe0273db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f51fde367ae in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f51fde3bb4d in  () at /usr/lib/libQt5Core.so.5
#7  0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 5 (Thread 0x7f51d3e30700 (LWP 6270)):
#0  0x00007f51fd3ed97b in poll () at /usr/lib/libc.so.6
#1  0x00007f51f73eaff3 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f51f73eb10e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f51fe085314 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f51fe0273db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f51fde367ae in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x0000563f709ada1a in RKFrontendTransmitter::run() ()
#7  0x00007f51fde3bb4d in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7f51dfb59700 (LWP 6269)):
#0  0x00007f51fe084be0 in  () at /usr/lib/libQt5Core.so.5
#1  0x00007f51fe08339a in QTimerInfoList::updateCurrentTime() () at /usr/lib/libQt5Core.so.5
#2  0x00007f51fe083976 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/libQt5Core.so.5
#3  0x00007f51fe08505f in  () at /usr/lib/libQt5Core.so.5
#4  0x00007f51f73ea519 in g_main_context_prepare () at /usr/lib/libglib-2.0.so.0
#5  0x00007f51f73eaf1e in  () at /usr/lib/libglib-2.0.so.0
#6  0x00007f51f73eb10e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#7  0x00007f51fe085314 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#8  0x00007f51fe0273db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#9  0x00007f51fde367ae in QThread::exec() () at /usr/lib/libQt5Core.so.5
#10 0x00007f52008be416 in  () at /usr/lib/libQt5DBus.so.5
#11 0x00007f51fde3bb4d in  () at /usr/lib/libQt5Core.so.5
#12 0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#13 0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7f51e7e12700 (LWP 6268)):
#0  0x00007f51fd3ed97b in poll () at /usr/lib/libc.so.6
#1  0x00007f51f3dac180 in  () at /usr/lib/libxcb.so.1
#2  0x00007f51f3dade4b in xcb_wait_for_event () at /usr/lib/libxcb.so.1
#3  0x00007f51ea9b882a in  () at /usr/lib/libQt5XcbQpa.so.5
#4  0x00007f51fde3bb4d in  () at /usr/lib/libQt5Core.so.5
#5  0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#6  0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7f51ebd77700 (LWP 6267)):
#0  0x00007f51fbda53bd in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f51fdab85bd in __gthread_cond_wait (__mutex=<optimized out>, __cond=<optimized out>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu/bits/gthr-default.h:864
#2  0x00007f51fdab85bd in std::condition_variable::wait(std::unique_lock<std::mutex>&) (this=<optimized out>, __lock=...) at /build/gcc/src/gcc/libstdc++-v3/src/c++11/condition_variable.cc:53
#3  0x00007f5204cb2d09 in  () at /usr/lib/libQt5WebKit.so.5
#4  0x00007f5204cb2e59 in  () at /usr/lib/libQt5WebKit.so.5
#5  0x00007f51fdabeb9f in std::execute_native_thread_routine(void*) (__p=0x563f70d8a580) at /build/gcc/src/gcc/libstdc++-v3/src/c++11/thread.cc:83
#6  0x00007f51fbd9f08c in start_thread () at /usr/lib/libpthread.so.0
#7  0x00007f51fd3f7e7f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7f5206494640 (LWP 6265)):
[KCrash Handler]
#6  0x00007f51fd336860 in raise () at /usr/lib/libc.so.6
#7  0x00007f51fd337ec9 in abort () at /usr/lib/libc.so.6
#8  0x00007f51fd379437 in __libc_message () at /usr/lib/libc.so.6
#9  0x00007f51fd37f78b in  () at /usr/lib/libc.so.6
#10 0x00007f51fd38124c in _int_free () at /usr/lib/libc.so.6
#11 0x00007f5188134282 in std::locale::_Impl::_M_install_facet(std::locale::id const*, std::locale::facet const*) () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#12 0x00007f5188140de3 in std::locale::_Impl::_Impl(unsigned long) () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#13 0x00007f5188141d55 in std::locale::_S_initialize_once() () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#14 0x00007f51fbda6def in __pthread_once_slow () at /usr/lib/libpthread.so.0
#15 0x00007f5188141da1 in std::locale::_S_initialize() () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#16 0x00007f5188141de3 in std::locale::locale() () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#17 0x00007f51881136a4 in std::ios_base::Init::Init() () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#18 0x00007f518810b7b8 in  () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#19 0x00007f518810b7ea in  () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#20 0x00007f520636547a in call_init.part () at /lib64/ld-linux-x86-64.so.2
#21 0x00007f5206365586 in _dl_init () at /lib64/ld-linux-x86-64.so.2
#22 0x00007f5206369a5e in dl_open_worker () at /lib64/ld-linux-x86-64.so.2
#23 0x00007f51fd433b64 in _dl_catch_error () at /usr/lib/libc.so.6
#24 0x00007f520636927a in _dl_open () at /lib64/ld-linux-x86-64.so.2
#25 0x00007f51fa5fee86 in  () at /usr/lib/libdl.so.2
#26 0x00007f51fd433b64 in _dl_catch_error () at /usr/lib/libc.so.6
#27 0x00007f51fa5ff587 in  () at /usr/lib/libdl.so.2
#28 0x00007f51fa5fef22 in dlopen () at /usr/lib/libdl.so.2
#29 0x00007f51fe024b1e in  () at /usr/lib/libQt5Core.so.5
#30 0x00007f51fe01e079 in QLibrary::load() () at /usr/lib/libQt5Core.so.5
#31 0x00007f5202d3c291 in  () at /usr/lib/libQt5WebKit.so.5
#32 0x00007f5202d1f838 in  () at /usr/lib/libQt5WebKit.so.5
#33 0x00007f5202d1c941 in  () at /usr/lib/libQt5WebKit.so.5
#34 0x00007f5202d1d312 in  () at /usr/lib/libQt5WebKit.so.5
#35 0x00007f5202cfabdb in  () at /usr/lib/libQt5WebKit.so.5
#36 0x00007f5203ea51ac in WebCore::Page::pluginData() const () at /usr/lib/libQt5WebKit.so.5
#37 0x00007f5203a6841b in  () at /usr/lib/libQt5WebKit.so.5
#38 0x00007f5203db01c0 in  () at /usr/lib/libQt5WebKit.so.5
#39 0x00007f5203db078b in  () at /usr/lib/libQt5WebKit.so.5
#40 0x00007f520408ce8b in  () at /usr/lib/libQt5WebKit.so.5
#41 0x00007f5203e1be6e in  () at /usr/lib/libQt5WebKit.so.5
#42 0x00007f5203e055c4 in  () at /usr/lib/libQt5WebKit.so.5
#43 0x00007f520413d907 in  () at /usr/lib/libQt5WebKit.so.5
#44 0x00007f520413912a in  () at /usr/lib/libQt5WebKit.so.5
#45 0x00007f520413e11d in  () at /usr/lib/libQt5WebKit.so.5
#46 0x00007f51fe0596c6 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#47 0x00007f5200dd5324 in  () at /usr/lib/libQt5Network.so.5
#48 0x00007f5200e8d662 in  () at /usr/lib/libQt5Network.so.5
#49 0x00007f51fe05a112 in QObject::event(QEvent*) () at /usr/lib/libQt5Core.so.5
#50 0x00007f51ff038fec in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#51 0x00007f51ff0409c6 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#52 0x00007f51fe028da0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#53 0x00007f51fe02ba06 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/libQt5Core.so.5
#54 0x00007f51fe085d04 in  () at /usr/lib/libQt5Core.so.5
#55 0x00007f51f73eae38 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#56 0x00007f51f73eb081 in  () at /usr/lib/libglib-2.0.so.0
#57 0x00007f51f73eb10e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#58 0x00007f51fe0852f1 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#59 0x00007f51eaa40482 in  () at /usr/lib/libQt5XcbQpa.so.5
#60 0x00007f51fe0273db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#61 0x00007f51fe0307d8 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#62 0x0000563f7082965c in main ()

> If it is a webkit problem any pointers were to look into?

Well, not sure how to track this down. But from the two backtraces: Thread 1 is the active thread, i.e. the one to look at. Here are some relevant lines from that:

[just a few more step to the crash, now, looks like an invalid free()]
#9  0x00007fc59460e599 in _int_free () at /usr/lib/libc.so.6
[everything in between happens inside jre/lib/libdeploy.so]
#18 0x00007fc5126a67ea in  () at /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so
#19 0x00007fc59d63a51a in call_init.part () at /lib64/ld-linux-x86-64.so.2
[...]
#27 0x00007fc5918b2f22 in dlopen () at /usr/lib/libdl.so.2
[...]
#29 0x00007fc59529f429 in QLibrary::load() () at /usr/lib/libQt5Core.so.5
[...]
#35 0x00007fc59b17e19c in WebCore::Page::pluginData() const () at /usr/lib/libQt5WebKit.so.5

So, in essence, what's happening is that QtWebKit is trying to load some plugin. That plugin loads /usr/lib/jvm/java-9-jre/jre/lib/libdeploy.so (possibly as one out of several libraries). Then while initializing that, there is an invalid free.

What we can conclude up to here is that it's some java-based plugin. Which exactly? You could try attaching strace to the running session (before you trigger the crash) as

  strace -p PID_OF_RKWARD (not rkward.rbackend)

That might generate some further hints.

Any updates? Did you get a chance to try strace on the problem?

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Sorry for the extremely long time to respond to this.

It is still affecting one of my systems and changing Java doesn't seem to help.

I did an strace on the rkward process.

The output file is quite big so instead of copy pasting here it can be seen at the link below:

https://1drv.ms/t/s!Apk6A1i6O8mluXucwdPpUxTIidm5

I just loaded a library went into its help page with ? and then cklicked on index and then the crash happened.

Thanks. Some of the last few lines that look ok are (starting at line 8658):

access("/usr/share/icedtea-web/lib/IcedTeaPlugin.so", F_OK) = 0
access("/usr/lib/mozilla/plugins/libflashplayer.so", F_OK) = 0
access("/usr/lib/jvm/java-10-jre/jre/lib/libnpjp2.so", F_OK) = 0
statx(AT_FDCWD, "/usr/lib/jvm/java-10-jre/jre/lib/libnpjp2.so", AT_STATX_SYNC_AS_STAT, STATX_ALL, {stx_mask=STATX_ALL, stx_attributes=0, stx_mode=S_IFREG|0755, stx_size=175104, ...}) = 0

Where, looking a few lines above, libnpjp2.so is resolved from a symlink inside the mozilla plugins:

readlink("/usr/lib/mozilla/plugins/libnpjp2-jre10.so", "/usr/lib/jvm/java-10-jre/jre/lib"..., 4095) = 44

I'm not quite sure, which of the three plugins is being loaded, first, but then we see loading of jre/libdeploy.so, as we had observed, before, then things start going wrong.

Perhaps you can try moving the plugins out of the way one by one, to see, which one is causing the issue. My first guess would be IcedTea.

Thanks a lot for your suggestions.

Finnaly it got fixed. I unistalled all kinds of plugins I saw, not simply moved, just to be certain.

However, removing, IcedTea, flash, aspera didn't help, pressing the index link of a help page would still crush Rkward.

In the end I removed the:
/usr/lib/mozilla/plugins/libnpjp2-jdk10.so
/usr/lib/mozilla/plugins/libnpjp2-jre10.so

and then Rkward stopped crashing, so now pressing the index or searching with ?? works again, great.

I did an strace after the fix as well and just quickly looked for jre/jdk but nothing popped up, so is java not needed for showing help pages?

Anyway, thanks for all the help.

Cheers

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!