kmix crashes whenever usb sound device is inserted/removed

[Bernie Bernstein]

Kmix crashes every time I insert or remove a usb sound device (usb headset).

Kmix version: 4:4.8.2-0ubuntu1
on Kubuntu 12.04

Here is the following stack trace from the crash report:

Application: KMix (kmix), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fb1857c0780 (LWP 7635))]

Thread 3 (Thread 0x7fb16642f700 (LWP 7636)):
#0 0x00007fb185084b03 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1 0x00007fb17ae90ff6 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x00007fb17ae91124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3 0x00007fb181e0b426 in QEventDispatcherGlib::processEvents (this=0x7fb1600008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4 0x00007fb181ddac82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5 0x00007fb181ddaed7 in QEventLoop::exec (this=0x7fb16642edd0, flags=...) at kernel/qeventloop.cpp:204
#6 0x00007fb181cd9fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7 0x00007fb181dba9ff in QInotifyFileSystemWatcherEngine::run (this=0x1fe8910) at io/qfilesystemwatcher_inotify.cpp:248
#8 0x00007fb181cdcfcb in QThreadPrivate::start (arg=0x1fe8910) at thread/qthread_unix.cpp:298
#9 0x00007fb17b9f7e9a in start_thread (arg=0x7fb16642f700) at pthread_create.c:308
#10 0x00007fb1850904bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fb165a22700 (LWP 7637)):
#0 0x00007fb1850830bd in read () at ../sysdeps/unix/syscall-template.S:82
#1 0x00007fb17aecb88f in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x00007fb17ae90abd in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3 0x00007fb17ae90f96 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4 0x00007fb17ae91124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5 0x00007fb181e0b426 in QEventDispatcherGlib::processEvents (this=0x7fb1540008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6 0x00007fb181ddac82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#7 0x00007fb181ddaed7 in QEventLoop::exec (this=0x7fb165a21dd0, flags=...) at kernel/qeventloop.cpp:204
#8 0x00007fb181cd9fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#9 0x00007fb181dba9ff in QInotifyFileSystemWatcherEngine::run (this=0x20b01d0) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007fb181cdcfcb in QThreadPrivate::start (arg=0x20b01d0) at thread/qthread_unix.cpp:298
#11 0x00007fb17b9f7e9a in start_thread (arg=0x7fb165a22700) at pthread_create.c:308
#12 0x00007fb1850904bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fb1857c0780 (LWP 7635)):
[KCrash Handler]
#6 0x0000000002066db0 in ?? ()
#7 0x00007fb1853b0e26 in MDWSlider::update (this=0x2099e20) at ../../kmix/gui/mdwslider.cpp:1001
#8 0x00007fb1853ac64b in ViewDockAreaPopup::refreshVolumeLevels (this=<optimized out>) at ../../kmix/gui/viewdockareapopup.cpp:168
#9 0x00007fb181df0281 in QMetaObject::activate (sender=0x2018110, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3547
#10 0x00007fb181df0281 in QMetaObject::activate (sender=0x2023430, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3547
#11 0x00007fb185385b0c in Mixer_Backend::readSetFromHW (this=0x2023430) at ../../kmix/backends/mixer_backend.cpp:155
#12 0x00007fb185395df5 in sink_cb (c=<optimized out>, i=<optimized out>, eol=<optimized out>) at ../../kmix/backends/mixer_pulse.cpp:191
#13 0x00007fb18376d944 in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#14 0x00007fb17b3af693 in ?? () from /usr/lib/x86_64-linux-gnu/libpulsecommon-1.1.so
#15 0x00007fb17b3afa03 in pa_pdispatch_run () from /usr/lib/x86_64-linux-gnu/libpulsecommon-1.1.so
#16 0x00007fb183763bdd in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#17 0x00007fb17b3b42a9 in ?? () from /usr/lib/x86_64-linux-gnu/libpulsecommon-1.1.so
#18 0x00007fb183551ab3 in ?? () from /usr/lib/x86_64-linux-gnu/libpulse-mainloop-glib.so.0
#19 0x00007fb17ae90c9a in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007fb17ae91060 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fb17ae91124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007fb181e0b3bf in QEventDispatcherGlib::processEvents (this=0x1c51ad0, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#23 0x00007fb182af5d6e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#24 0x00007fb181ddac82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#25 0x00007fb181ddaed7 in QEventLoop::exec (this=0x7fff0e891990, flags=...) at kernel/qeventloop.cpp:204
#26 0x00007fb181ddff67 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#27 0x00007fb18539d3e2 in kdemain (argc=5, argv=0x7fff0e891f18) at ../../kmix/apps/main.cpp:76
#28 0x00007fb184fbf76d in __libc_start_main (main=0x400630 <main(int, char**)>, argc=5, ubp_av=0x7fff0e891f18, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff0e891f08) at libc-start.c:226
#29 0x0000000000400661 in _start ()