I observe the same issue on Fedora 18 with Radeon HD 5670:

[KCrash Handler]
#6  __memset_sse2 () at ../sysdeps/x86_64/memset.S:873
#7  0x00007f59a39eaff2 in memset (__len=<optimized out>, __ch=204, __dest=<optimized out>) at /usr/include/bits/string3.h:84
#8  r600_texture_create_object (screen=screen@entry=0x1f317a0, base=base@entry=0x7fff57798810, pitch_in_bytes_override=pitch_in_bytes_override@entry=0, buf=buf@entry=0x0, surface=surface@entry=0x7fff57797b10) at r600_texture.c:509
#9  0x00007f59a39eb2c7 in r600_texture_create (screen=0x1f317a0, templ=0x7fff57798810) at r600_texture.c:601
#10 0x00007f59a39fda25 in dri2_drawable_process_buffers (att_count=1, atts=0x7fff577988f0, buffer_count=1, buffers=0x1e9fe80, drawable=0x1e9ff20) at dri2.c:254
#11 dri2_allocate_textures (drawable=0x1e9ff20, statts=0x7fff577988f0, statts_count=1) at dri2.c:404
#12 0x00007f59a39fc595 in dri_st_framebuffer_validate (stfbi=<optimized out>, statts=0x7fff577988f0, count=1, out=0x0) at dri_drawable.c:81
#13 0x00007f59a39fc7ce in dri_drawable_validate_att (statt=ST_ATTACHMENT_FRONT_LEFT, drawable=0x1e9ff20) at dri_drawable.c:206
#14 dri_set_tex_buffer2 (pDRICtx=<optimized out>, target=3553, format=8409, dPriv=<optimized out>) at dri_drawable.c:220
#15 0x000000304bacb3c3 in loadTexture (depth=24, size=..., pix=<optimized out>, this=0x1ea0b70) at /usr/src/debug/kde-workspace-4.10.1/kwin/glxbackend.cpp:716
#16 KWin::GlxTexture::loadTexture (this=0x1ea0b70, pix=<optimized out>, size=..., depth=24) at /usr/src/debug/kde-workspace-4.10.1/kwin/glxbackend.cpp:658
#17 0x000000304bac30d5 in KWin::SceneOpenGL::Window::bindTexture (this=0x2184e10) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene_opengl.cpp:822
#18 0x000000304bac9a8e in KWin::SceneOpenGL::Window::performPaint (this=this@entry=0x2184e10, mask=mask@entry=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene_opengl.cpp:931
#19 0x000000304bac249f in KWin::SceneOpenGL2::performPaintWindow (this=this@entry=0x1fc3af0, w=w@entry=0x1ef75c0, mask=mask@entry=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene_opengl.cpp:566
#20 0x000000304bac263d in KWin::SceneOpenGL2::finalDrawWindow (this=0x1fc3af0, w=w@entry=0x1ef75c0, mask=mask@entry=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene_opengl.cpp:551
#21 0x000000304bad63a5 in KWin::EffectsHandlerImpl::drawWindow (this=0x2170db0, w=w@entry=0x1ef75c0, mask=mask@entry=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/effects.cpp:318
#22 0x000000304bab585a in KWin::Scene::finalPaintWindow (this=<optimized out>, w=0x1ef75c0, mask=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene.cpp:449
#23 0x000000304bad6627 in KWin::EffectsHandlerImpl::paintWindow (this=0x2170db0, w=0x1ef75c0, mask=mask@entry=1, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/effects.cpp:281
#24 0x000000304bab841d in KWin::Scene::paintWindow (this=<optimized out>, w=0x2184e10, mask=1, region=..., quads=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene.cpp:356
#25 0x000000304bab774f in KWin::Scene::paintSimpleScreen (this=this@entry=0x1fc3af0, orig_mask=orig_mask@entry=0, region=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene.cpp:342
#26 0x000000304bab579e in KWin::Scene::finalPaintScreen (this=0x1fc3af0, mask=0, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene.cpp:186
#27 0x000000304bad67f0 in KWin::EffectsHandlerImpl::paintScreen (this=0x2170db0, mask=0, region=..., data=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/effects.cpp:254
#28 0x000000304bab6b38 in KWin::Scene::paintScreen (this=0x1fc3af0, mask=0x7fff57799444, region=0x7fff577994f0) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene.cpp:140
#29 0x000000304bac5f9e in KWin::SceneOpenGL::paint (this=0x1fc3af0, damage=..., toplevels=...) at /usr/src/debug/kde-workspace-4.10.1/kwin/scene_opengl.cpp:308
#30 0x000000304bab0f5c in KWin::Compositor::performCompositing (this=this@entry=0x1e65b30) at /usr/src/debug/kde-workspace-4.10.1/kwin/composite.cpp:610
#31 0x000000304bab1a10 in KWin::Compositor::slotCompositingOptionsInitialized (this=0x1e65b30) at /usr/src/debug/kde-workspace-4.10.1/kwin/composite.cpp:275
#32 0x000000399df8ceef in QMetaObject::activate (sender=0x1edf240, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3539
#33 0x000000399de6c5d7 in QFutureWatcherBase::event (this=<optimized out>, event=0x7f59a4001770) at concurrent/qfuturewatcher.cpp:344
#34 0x00000030439ca5cc in QApplicationPrivate::notify_helper (this=this@entry=0x1d38570, receiver=receiver@entry=0x1edf240, e=e@entry=0x7f59a4001770) at kernel/qapplication.cpp:4562
#35 0x00000030439cea4a in QApplication::notify (this=0x7fff5779a3f0, receiver=0x1edf240, e=0x7f59a4001770) at kernel/qapplication.cpp:4423
#36 0x00000030448473c6 in KApplication::notify (this=0x7fff5779a3f0, receiver=0x1edf240, event=0x7f59a4001770) at /usr/src/debug/kdelibs-4.10.1/kdeui/kernel/kapplication.cpp:311
#37 0x000000399df77abe in QCoreApplication::notifyInternal (this=0x7fff5779a3f0, receiver=receiver@entry=0x1edf240, event=event@entry=0x7f59a4001770) at kernel/qcoreapplication.cpp:946
#38 0x000000399df7b571 in sendEvent (event=0x7f59a4001770, receiver=0x1edf240) at kernel/qcoreapplication.h:231
#39 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x1ce1360) at kernel/qcoreapplication.cpp:1570
#40 0x0000003043a6b3bc in sendPostedEvents () at ../../src/corelib/kernel/qcoreapplication.h:236
#41 QEventDispatcherX11::processEvents (this=0x1ce2cc0, flags=...) at kernel/qeventdispatcher_x11.cpp:75
#42 0x000000399df7680f in QEventLoop::processEvents (this=this@entry=0x7fff5779a100, flags=...) at kernel/qeventloop.cpp:149
#43 0x000000399df76a98 in QEventLoop::exec (this=0x7fff5779a100, flags=...) at kernel/qeventloop.cpp:204
#44 0x000000399df7b888 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1218
#45 0x000000304ba67d6a in kdemain (argc=1, argv=0x7fff5779a538) at /usr/src/debug/kde-workspace-4.10.1/kwin/main.cpp:537
#46 0x0000003994c21a05 in __libc_start_main (main=0x400960 <main(int, char**)>, argc=1, ubp_av=0x7fff5779a538, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff5779a528) at libc-start.c:225
#47 0x0000000000400991 in _start ()