compiz (switcher plugin) crashes on Alt+Tab using LLVMpipe

Using LLVMpipe and the swticher plugin, compiz crashes as soon as I hit Alt+Tab. Looks like yet another problem with mipmapping:

(gdb) where
#0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1 0x00007fc43cfe925b in lp_rast_finish () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#2 0x00007fc43cfee2a5 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#3 0x00007fc43cfee8db in lp_setup_bind_framebuffer () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#4 0x00007fc43cff908c in llvmpipe_set_framebuffer_state () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#5 0x00007fc43c37153c in cso_set_framebuffer () from /usr/lib/x86_64-linux-gnu/dri/libgallium.so
#6 0x00007fc43c3ca957 in util_gen_mipmap () from /usr/lib/x86_64-linux-gnu/dri/libgallium.so
#7 0x00007fc43c45aef0 in st_generate_mipmap () from /usr/lib/x86_64-linux-gnu/dri/libgallium.so
#8 0x00007fc43cb87fde in _mesa_GenerateMipmapEXT () from /usr/lib/x86_64-linux-gnu/dri/libdricore.so
#9 0x00007fc43e09dc20 in GLTexture::enable (this=0x1165040, filter=<optimised out>) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/texture.cpp:230
#10 0x00007fc43e09dcd8 in TfpTexture::enable (this=0x1165040, filter=GLTexture::Good) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/texture.cpp:616
#11 0x00007fc43e0a305f in enableFragmentOperationsAndDrawGeometry (mask=720896, filter=GLTexture::Good, attrib=..., texture=0x1165040, w=0xf23cc0, gs=0xc21b80) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:1106
#12 GLWindow::glDrawTexture (this=0xf23cc0, texture=0x1165040, attrib=..., mask=720896) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:1174
#13 0x00007fc43e0a3d5a in GLWindow::glDraw (this=0xf23cc0, transform=..., fragment=..., region=..., mask=720896) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:1225
#14 0x00007fc431ccafe9 in DecorWindow::glDraw (this=0xf20590, transform=..., attrib=..., region=..., mask=196608) at /home/dan/bzr/compiz/trunk/plugins/decor/src/decor.cpp:162
#15 0x00007fc43e0a3baa in GLWindow::glDraw (this=0xf23cc0, transform=..., fragment=..., region=..., mask=196608) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:1184
#16 0x00007fc431893ed8 in BaseSwitchWindow::paintThumb (this=0xf20080, attrib=..., transform=..., mask=196608, x=626, y=504, width1=192, height1=172, width2=159, height2=144)
    at /home/dan/bzr/compiz/trunk/plugins/compiztoolbox/src/compiztoolbox.cpp:491
#17 0x00007fc4306aed08 in SwitchWindow::paintThumb (this=<optimised out>, attrib=..., transform=..., mask=<optimised out>, x=<optimised out>, y=<optimised out>) at /home/dan/bzr/compiz/trunk/plugins/switcher/src/switcher.cpp:875
#18 0x00007fc4306b262f in SwitchWindow::glPaint (this=0x1c0b130, attrib=..., transform=..., region=..., mask=0) at /home/dan/bzr/compiz/trunk/plugins/switcher/src/switcher.cpp:988
#19 0x00007fc43e0a3efc in GLWindow::glPaint (this=0x3087730, attrib=..., transform=..., region=..., mask=0) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:1237
#20 0x00007fc4306b2dea in SwitchScreen::glPaintOutput (this=<optimised out>, sAttrib=..., transform=..., region=..., output=0xbd85e0, mask=70) at /home/dan/bzr/compiz/trunk/plugins/switcher/src/switcher.cpp:810
#21 0x00007fc43e0a4829 in GLScreen::glPaintOutput (this=0xc21b80, sAttrib=..., transform=..., region=..., output=0xbd85e0, mask=<optimised out>) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/paint.cpp:482
#22 0x00007fc43e0b7daf in PrivateGLScreen::paintOutputs (this=0xc21bf0, outputs=..., mask=5, region=...) at /home/dan/bzr/compiz/trunk/plugins/opengl/src/screen.cpp:1164
#23 0x00007fc43e6e79a3 in CompositeScreen::paint (this=0xc11e00, outputs=..., mask=<optimised out>) at /home/dan/bzr/compiz/trunk/plugins/composite/src/screen.cpp:869
#24 0x00007fc43e6e97ef in CompositeScreen::handlePaintTimeout (this=0xc11e00) at /home/dan/bzr/compiz/trunk/plugins/composite/src/screen.cpp:831
#25 0x00007fc443539c3b in operator() (this=<optimised out>) at /usr/include/boost/function/function_template.hpp:1013
#26 CompTimer::triggerCallback (this=<optimised out>) at /home/dan/bzr/compiz/trunk/src/timer/src/timer.cpp:227
#27 0x00007fc443539d3f in CompTimeoutSource::callback (this=<optimised out>) at /home/dan/bzr/compiz/trunk/src/timer/src/timer.cpp:150
#28 0x00007fc4435391ed in operator() (this=<optimised out>) at /usr/include/sigc++-2.0/sigc++/functors/slot.h:440
#29 dispatch (slot=<optimised out>, this=<optimised out>) at /home/dan/bzr/compiz/trunk/src/timer/src/timer.cpp:133
#30 CompTimeoutSource::dispatch (this=<optimised out>, slot=<optimised out>) at /home/dan/bzr/compiz/trunk/src/timer/src/timer.cpp:131
#31 0x00007fc441a34f2f in Glib::Source::dispatch_vfunc(_GSource*, int (*)(void*), void*) () from /usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1
#32 0x00007fc44153cd53 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007fc44153d0a0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#34 0x00007fc44153d49a in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#35 0x000000000040235d in main (argc=16, argv=0x7fff73f46c88) at /home/dan/bzr/compiz/trunk/src/main.cpp:260
(gdb) quit