gnome applications freezing

Since today upgrade some gnome/gtk based applications freeze ... Somehow it even blocks
access to other applications as well. That is alt-tab does not work! I had to switch to console
and kill offending program to restore functionality. Google chome, gvim -- and possibly other
applications are affected in similar fashion. It seems applications sits in pa_threaded_mainloop_wait()
forever ...

$ gdb -p `pidof meld`

(gdb) bt
#0 pthread_cond_wait@@GLIBC_2.3.2 ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:142
#1 0x00007f022b7bd970 in pa_threaded_mainloop_wait () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#2 0x00007f022b9d9662 in pulse_driver_play ()
   from /usr/lib/x86_64-linux-gnu/libcanberra-0.28/libcanberra-pulse.so
#3 0x00007f023463c83b in ca_context_play_full () from /usr/lib/x86_64-linux-gnu/libcanberra.so.0
#4 0x00007f023484bb4f in ca_gtk_play_for_widget ()
   from /usr/lib/x86_64-linux-gnu/libcanberra-gtk.so.0
#5 0x00007f0234a50bce in ?? ()
   from /usr/lib/x86_64-linux-gnu/gtk-2.0/modules/libcanberra-gtk-module.so
#6 0x00007f0234a51983 in ?? ()
   from /usr/lib/x86_64-linux-gnu/gtk-2.0/modules/libcanberra-gtk-module.so
#7 0x00007f023a555d76 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0
#8 0x00007f023c1d7b2a in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9 0x00007f023c1d7ef0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007f023c1d82ea in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#11 0x00007f023a91e437 in gtk_main () from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#12 0x00007f023afd1026 in ?? () from /usr/lib/python2.7/dist-packages/gtk-2.0/gtk/_gtk.so
#13 0x00000000004b7177 in PyEval_EvalFrameEx ()
#14 0x00000000004b6db7 in PyEval_EvalFrameEx ()
#15 0x00000000004bcd4d in PyEval_EvalCodeEx ()
#16 0x00000000004bd822 in PyEval_EvalCode ()
#17 0x00000000004dcd02 in run_mod ()
#18 0x00000000004dd8c4 in PyRun_FileExFlags ()
#19 0x00000000004de33e in PyRun_SimpleFileExFlags ()
#20 0x00000000004ee79d in Py_Main ()
#21 0x00007f023caf376d in __libc_start_main (main=0x41ab50 <main>, argc=2, ubp_av=0x7fff0bfc3288,
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff0bfc3278)
    at libc-start.c:226
#22 0x000000000041ccd9 in _start ()
#0 0x00007f023cbb6dc3 in __GI___poll (fds=<optimized out>, nfds=<optimized out>,
    timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1 0x00007f022b7bd34f in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#2 0x00007f022b7ae76c in pa_mainloop_poll () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#3 0x00007f022b7aedd9 in pa_mainloop_iterate () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#4 0x00007f022b7aee90 in pa_mainloop_run () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#5 0x00007f022b7bd2ff in ?? () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#6 0x00007f022b366c28 in ?? () from /usr/lib/x86_64-linux-gnu/libpulsecommon-1.1.so
#7 0x00007f023ddace9a in start_thread (arg=0x7f022a597700) at pthread_create.c:308
#8 0x00007f023cbc277d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#9 0x0000000000000000 in ?? ()

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: libcanberra-pulse 0.28-3ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-15.24-generic 3.2.5
Uname: Linux 3.2.0-15-generic x86_64
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
Date: Thu Feb 9 18:25:54 2012
InstallationMedia: Kubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/usr/bin/zsh
SourcePackage: libcanberra
UpgradeStatus: Upgraded to precise on 2012-01-07 (32 days ago)