Bug 87244

Please see the directions in #87051 for getting a backtrace and include on here.  It's almost impossible to debug crashes without them.

I tried to follow your directions #87051 for getting a backtrace but it did now work. Probably there is some step missing. Something that is too obvious for you to remember mentioning it.

- Opened konsole.
- Typed screen <enter>
- Typed gdb juk <enter>
- gdb copyright and "(gdb)" prompt appeared. That's all. juk DID NOT START AT ALL.

Now your instructions say "logout". I did not know whether I should close gdb and Konsole  before logging out. I decided that I should NOT. So I let the logout process kill my Konsole with screen and gdb. Then I logged back in and types "screen -r". The gdb session appeared with gdb prompt and no useful info.

Ah, yes -- you need to type "run" to start it in gdb.

OK. Here's what I did.
(gdb) run
Starting program: /usr/kde3.3/bin/juk

Program exited normally.


You see that gdb says "Program exited normally." But juk is in fact running. It DID NOT EXIT. But gdb thinks it exited. 

What should I do now.

Heh -- sorry forgot one more thing.  For running in gdb you have to pass the "--nofork" parameter, so instead of "run" use "run --nofork".

Also, note that it's considered rude to use all caps; you're perfectly clear without that.  ;-)

OK. Sorry about capitals. Here's the gdb output:
===
Starting program: /usr/kde3.3/bin/juk --nofork
kio (KDirWatch): Can't use FAM (fam daemon not running?)
kio (KDirWatch): Available methods: Stat
kio (KDirWatch): addDir - recursive/watchFiles not supported in KDE 3.0
kio (KDirWatch): Added Dir /home/nobackup/mp3burned [KDirWatch-1]
kio (KDirWatch): Global Poll Freq is now 500 msec
kio (KDirWatch):  Started Polling Timer, freq 500
kio (KDirWatch):  Setup Stat (freq 500) for /home/nobackup/mp3burned
juk: [virtual void StatusLabel::updateData()]
kio (KSycoca): Trying to open ksycoca from /var/tmp/kdecache-milos/ksycoca
juk: [virtual void StatusLabel::updateData()]
juk: [virtual void StatusLabel::updateData()]
juk: [virtual void StatusLabel::updateData()]
juk: [virtual void StatusLabel::updateCurrent()]
juk: [virtual void StatusLabel::updateData()]
kio (KDirWatch):  Stopped Polling Timer
kio (KDirWatch): Removed Dir /home/nobackup/mp3burned [KDirWatch-1]
kio (KDirWatch): Poll Freq now 3600000 msec

Program received signal SIGSEGV, Segmentation fault.
0x624f7473 in ?? ()
===

Is it helpful?

Close -- but you still didn't type "backtrace" to get a backtrace when it crashed.

Sorry. Here it is:

(gdb) backtrace
#0  0x624f7473 in ?? ()
#1  0x08086345 in PlayerManager::qt_invoke(int, QUObject*) ()
#2  0x412503c7 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#3  0x412501c3 in QObject::activate_signal(int) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#4  0x40b30cc5 in KAction::activated() () from /usr/kde3.3/lib/libkdeui.so.4
#5  0x40b3027c in KAction::slotActivated() ()
   from /usr/kde3.3/lib/libkdeui.so.4
#6  0x40b30252 in KAction::activate() () from /usr/kde3.3/lib/libkdeui.so.4
#7  0x0808044f in JuK::queryExit() ()
#8  0x40b87f55 in KMainWindow::shuttingDown() ()
   from /usr/kde3.3/lib/libkdeui.so.4
#9  0x40b88819 in KMainWindow::qt_invoke(int, QUObject*) ()
   from /usr/kde3.3/lib/libkdeui.so.4
#10 0x08080879 in JuK::qt_invoke(int, QUObject*) ()
#11 0x412503c7 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#12 0x412501c3 in QObject::activate_signal(int) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#13 0x40da6bf8 in KApplication::shutDown() ()
   from /usr/kde3.3/lib/libkdecore.so.4
#14 0x40da6d9c in KApplication::qt_emit(int, QUObject*) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/kde3.3/lib/libkdecore.so.4
#15 0x40e4b8e3 in KUniqueApplication::qt_emit(int, QUObject*) ()
   from /usr/kde3.3/lib/libkdecore.so.4
#16 0x41250404 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#17 0x412501c3 in QObject::activate_signal(int) ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#18 0x41555246 in QApplication::aboutToQuit() ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#19 0x41207b5f in QEventLoop::enterLoop() ()
   from /usr/kde3.3/lib/libqt-mt.so.3
#20 0x41207a14 in QEventLoop::exec() () from /usr/kde3.3/lib/libqt-mt.so.3
#21 0x411f6ce0 in QApplication::exec() () from /usr/kde3.3/lib/libqt-mt.so.3
#22 0x08083c5e in main ()
#23 0x41acfc57 in __libc_start_main () from /lib/i686/libc.so.6

It seems to be crashing while trying to activate the "stop" action.  This should only happen if the PlayerManager instance was destructed though, which shouldn't happen by that time (actually I can't find a place where it does happen).  Odd.

It crashes when a user invokes logout while the JuK window is opened. It does not crash when a user invokes logout while the JuK window is minimized.

CVS commit by mpyne: 

Move some destructor code into the JuK class dtor.  Hopefully this will fix bug 87244, as it fixed the crash on my system.

Reporter:  If it doesn't fix the bug, feel free to reopen it.

CCMAIL:87244-done@bugs.kde.org


  M +4 -5      juk.cpp   1.223


--- kdemultimedia/juk/juk.cpp  #1.222:1.223
@@ -76,5 +76,8 @@ JuK::JuK(QWidget *parent, const char *na
 JuK::~JuK()
 {
-
+    action("stop")->activate();
+    delete m_systemTray;
+    m_systemTray = 0;
+    delete m_splitter;
 }
 
@@ -345,11 +348,7 @@ bool JuK::queryExit()
 
     hide();
-    action("stop")->activate();
-    delete m_systemTray;
-    m_systemTray = 0;
 
     Cache::instance()->save();
     saveConfig();
-    delete m_splitter;
     return true;
 }

CVS commit by mpyne: 

Backport fix for bug 87244 to KDE 3.3.

CCMAIL:87244@bugs.kde.org


  M +4 -5      juk.cpp   1.214.2.3


--- kdemultimedia/juk/juk.cpp  #1.214.2.2:1.214.2.3
@@ -74,5 +74,8 @@ JuK::JuK(QWidget *parent, const char *na
 JuK::~JuK()
 {
-
+    action("stop")->activate();
+    delete m_systemTray;
+    m_systemTray = 0;
+    delete m_splitter;
 }
 
@@ -330,11 +333,7 @@ bool JuK::queryExit()
 
     hide();
-    action("stop")->activate();
-    delete m_systemTray;
-    m_systemTray = 0;
 
     Cache::instance()->save();
     saveConfig();
-    delete m_splitter;
     return true;
 }