Bug#797404: Backtrace

[Maximiliano Curia]

On 30/08/15 20:00, Adrián Arévalo Tirado wrote:
> Here's the backtrace if it serves as any help:

> #3 0x7f44bb3eb9a7 in
> QEventDispatcherGlib::processEvents(QFlags) ()
> from /usr/lib/x86_64-linux-gnu/libQtCore.so.4

> #8 0x7f449e55bfd0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
> 
> #18 0x7f44b68590c1 in __dlopen (file=, mode= out>) at dlopen.c:87
> 
> #19 0x7f44a89e973f in ?? () from /usr/lib/libvlccore.so.8

Right, I've hit a similar bug yesterday.

tl;dr run sudo /usr/lib/vlc/vlc-cache-gen -f /usr/lib/vlc/plugins

The problem is that libqt4 and libqt5 can't be loaded in the same process.
What is happening here is that you have a qt4 application that tries to do
something with the audio, that loads a phonon plugin which happens to be
phonon-backend-vlc, that loads the libvlccore, which in turn checks if the
cached information about it's plugins is up-to-date and decides that it needs
to regenerate the cache, and one of the plugins is the qt5 gui interface.
Which ends the program with the informative backtrace you saw.

Now, this shouldn't happen, vlc-nox regenerates the cache whenever a new
plugins gets installed, but apparently this isn't as bullet proof as we need
it to be. :(

Manually running the vlc-cache-gen command as is done by the trigger handler
in vlc-nox or even simply installing/reinstalling any vlc providing plugin
package fixes the issue.

Happy hacking,
-- 
"If you think your users are idiots, only idiots will use it."
-- Linus Torvalds
Saludos /\/\ /\ >< `/



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Bug#797404: Backtrace

[Adrián Arévalo Tirado]

Here's the backtrace if it serves as any help:

Application: KNotify (knotify4), signal: Segmentation fault

Using host libthread_db library /lib/x86_64-linux-gnu/libthread_db.so.1.

[Current thread is 1 (Thread 0x7f44bdae4900 (LWP 18690))]


Thread 2 (Thread 0x7f44ab0ec700 (LWP 18691)):

#0 0x7f44bac5d53d in poll () at ../sysdeps/unix/syscall-template.S:81

#1 0x7f44b8296ebc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0

#2 0x7f44b8296fcc in g_main_context_iteration () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0

#3 0x7f44bb3eb9a7 in
QEventDispatcherGlib::processEvents(QFlagsQEventLoop::ProcessEventsFlag)
() from /usr/lib/x86_64-linux-gnu/libQtCore.so.4

#4 0x7f44bb3baec1 in
QEventLoop::processEvents(QFlagsQEventLoop::ProcessEventsFlag) () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4

#5 0x7f44bb3bb225 in
QEventLoop::exec(QFlagsQEventLoop::ProcessEventsFlag) () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4

#6 0x7f44bb2aeef9 in QThread::exec() () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4

#7 0x7f44bb39b633 in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4

#8 0x7f44bb2b186f in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4

#9 0x7f44b877e0a4 in start_thread (arg=0x7f44ab0ec700) at
pthread_create.c:309

#10 0x7f44bac6607d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:111


Thread 1 (Thread 0x7f44bdae4900 (LWP 18690)):

[KCrash Handler]

#6 __strcmp_ssse3 () at ../sysdeps/x86_64/multiarch/../strcmp.S:1859

#7 0x7f449e266c9f in QMetaType::registerNormalizedType(QByteArray
const, void (*)(void*), void* (*)(void const*), void (*)(void*), void*
(*)(void*, void const*), int, QFlagsQMetaType::TypeFlag, QMetaObject
const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5

#8 0x7f449e55bfd0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5

#9 0x7f44bd9b89fa in call_init (l=optimized out, argc=argc@entry=1,
argv=argv@entry=0x7ffe83e684f8, env=env@entry=0x9df330) at dl-init.c:78

#10 0x7f44bd9b8ae3 in call_init (env=0x9df330, argv=0x7ffe83e684f8,
argc=1, l=optimized out) at dl-init.c:36

#11 _dl_init (main_map=main_map@entry=0xc67dc0, argc=1,
argv=0x7ffe83e684f8, env=0x9df330) at dl-init.c:126

#12 0x7f44bd9bcc48 in dl_open_worker (a=a@entry=0x7ffe83e66538) at
dl-open.c:577

#13 0x7f44bd9b88b4 in _dl_catch_error
(objname=objname@entry=0x7ffe83e66528,
errstring=errstring@entry=0x7ffe83e66530,
mallocedp=mallocedp@entry=0x7ffe83e66527,
operate=operate@entry=0x7f44bd9bc970 dl_open_worker,
args=args@entry=0x7ffe83e66538)
at dl-error.c:187

#14 0x7f44bd9bc43b in _dl_open (file=0xc56d10
/usr/lib/vlc/plugins/gui/libqt4_plugin.so, mode=-2147483647,
caller_dlopen=optimized out, nsid=-2, argc=1, argv=0x7ffe83e684f8,
env=0x9df330) at dl-open.c:661

#15 0x7f44b685902b in dlopen_doit (a=a@entry=0x7ffe83e66750) at
dlopen.c:66

#16 0x7f44bd9b88b4 in _dl_catch_error (objname=0x8ac5e0,
errstring=0x8ac5e8, mallocedp=0x8ac5d8, operate=0x7f44b6858fd0
dlopen_doit, args=0x7ffe83e66750) at dl-error.c:187

#17 0x7f44b68595dd in _dlerror_run (operate=operate@entry=0x7f44b6858fd0
dlopen_doit, args=args@entry=0x7ffe83e66750) at dlerror.c:163

#18 0x7f44b68590c1 in __dlopen (file=optimized out, mode=optimized
out) at dlopen.c:87

#19 0x7f44a89e973f in ?? () from /usr/lib/libvlccore.so.8

#20 0x7f44a89cd87b in ?? () from /usr/lib/libvlccore.so.8

#21 0x7f44a89cdba8 in ?? () from /usr/lib/libvlccore.so.8

#22 0x7f44a89cdb04 in ?? () from /usr/lib/libvlccore.so.8

#23 0x7f44a89ce084 in ?? () from /usr/lib/libvlccore.so.8

#24 0x7f44a89ce67a in ?? () from /usr/lib/libvlccore.so.8

#25 0x7f44a89546fd in libvlc_InternalInit () from
/usr/lib/libvlccore.so.8

#26 0x7f44a8725a8b in libvlc_new () from /usr/lib/libvlc.so.5

#27 0x7f44a8c9b80b in ?? () from
/usr/lib/x86_64-linux-gnu/qt4/plugins/phonon_backend/phonon_vlc.so

#28 0x7f44a8c7d8d9 in ?? () from
/usr/lib/x86_64-linux-gnu/qt4/plugins/phonon_backend/phonon_vlc.so

#29 0x7f44a8c7e3d3 in qt_plugin_instance () from
/usr/lib/x86_64-linux-gnu/qt4/plugins/phonon_backend/phonon_vlc.so

#30 0x7f44bb39f6d3 in QPluginLoader::instance() () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4

#31 0x7f44aa6e1c1b in ?? () from
/usr/lib/kde4/plugins/phonon_platform/kde.so

#32 0x7f44aa6e23b7 in ?? () from
/usr/lib/kde4/plugins/phonon_platform/kde.so

#33 0x7f44bd0c6e06 in ?? () from
/usr/lib/x86_64-linux-gnu/libphonon.so.4

#34 0x7f44bd0c8258 in Phonon::Factory::backend(bool) () from
/usr/lib/x86_64-linux-gnu/libphonon.so.4

#35 0x7f44bd0c89a2 in ?? () from
/usr/lib/x86_64-linux-gnu/libphonon.so.4

#36 0x7f44bd0bc03f in ?? () from
/usr/lib/x86_64-linux-gnu/libphonon.so.4

#37 0x7f44bd0b952f in ?? () from
/usr/lib/x86_64-linux-gnu/libphonon.so.4

#38 0x0040e879 in _start ()