Felix points out this is being caused by compiz crashing. So it appears not to be an X or fglrx bug but rather something in nux:
Backtrace:
#0 0x0000000000000000 in ?? ()
#1 0x00007fffeb58fcf0 in nux::IOpenGLSurface::UnlockRect() ()
from /usr/lib/libnux-graphics-0.9.so.0
#2 0x00007fffeb58798a in nux::IOpenGLTexture2D::UnlockRect(int) ()
from /usr/lib/libnux-graphics-0.9.so.0
#3 0x00007fffeb55a545 in nux::CachedTexture2D::LoadMipLevel(nux::BaseTexture*, int) () from
/usr/lib/libnux-graphics-0.9.so.0
#4 0x00007fffeb55ae2d in nux::CachedTexture2D::CachedTexture2D(nux::NResourceSet*, nux::Texture2D*) () from
/usr/lib/libnux-graphics-0.9.so.0
#5 0x00007fffeb557b54 in nux::TGLResourceFactory<nux::Texture2D,
nux::CachedTexture2D>::BuildResource(nux::NResourceSet*, nux::ResourceData*) ()
from /usr/lib/libnux-graphics-0.9.so.0
#6 0x00007fffeb55736c in nux::NResourceCache::GetCachedResource(nux::ResourceData*) () from
/usr/lib/libnux-graphics-0.9.so.0
#7 0x00007fffeb54c8cd in nux::GraphicsEngine::CacheResource(nux::ResourceData*) () from
/usr/lib/libnux-graphics-0.9.so.0
#8 0x00007fffeb55a09f in nux::BaseTexture::GetDeviceTexture() ()
from /usr/lib/libnux-graphics-0.9.so.0
#9 0x00007fffebbbdfa1 in PanelHomeButton::Refresh() ()
from /usr/lib/compiz/libunityshell.so
#10 0x00007fffebbbe371 in PanelHomeButton::PanelHomeButton() ()
from /usr/lib/compiz/libunityshell.so
#11 0x00007fffebbc4b96 in PanelView::PanelView(char const*, int) ()
from /usr/lib/compiz/libunityshell.so
#12 0x00007fffebbde85c in UnityScreen::initLauncher(nux::NThread*, void*) ()
from /usr/lib/compiz/libunityshell.so
#13 0x00007fffebbdeabd in UnityScreen::initUnity(nux::NThread*, void*) ()
from /usr/lib/compiz/libunityshell.so
#14 0x00007fffeb919282 in nux::WindowThread::Run(void*) ()
from /usr/lib/libnux-0.9.so.0
#15 0x00007fffebbdf57a in UnityScreen::UnityScreen(CompScreen*) ()
from /usr/lib/compiz/libunityshell.so
#16 0x00007fffebbe1c49 in CompPlugin::VTableForScreenAndWindow<UnityScreen, UnityWindow>::initScreen(CompScreen*)
() from /usr/lib/compiz/libunityshell.so
#17 0x00000000004501fa in CompManager::initPlugin(CompPlugin*) ()
#18 0x00000000004512fe in CompPlugin::push(CompPlugin*) ()
#19 0x000000000042d588 in PrivateScreen::updatePlugins() ()
#20 0x000000000042d898 in PrivateScreen::processEvents() ()
#21 0x000000000042d8f8 in CompEventSource::callback() ()
#22 0x00007ffff6e4440f in Glib::Source::dispatch_vfunc(_GSource*, int (*)(void*), void*) () from
/usr/lib/libglibmm-2.4.so.1
#23 0x00007ffff6956c4d in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#24 0x00007ffff6957438 in ?? () from /lib/libglib-2.0.so.0
#25 0x00007ffff69576c9 in g_main_context_iteration ()
from /lib/libglib-2.0.so.0
#26 0x00007ffff6e452e3 in Glib::MainContext::iteration(bool) ()
from /usr/lib/libglibmm-2.4.so.1
#27 0x000000000042932a in CompScreen::eventLoop() ()
#28 0x00000000004222e0 in main ()
Felix points out this is being caused by compiz crashing. So it appears not to be an X or fglrx bug but rather something in nux:
Backtrace: face::UnlockRec t() () libnux- graphics- 0.9.so. 0 ture2D: :UnlockRect( int) () libnux- graphics- 0.9.so. 0 ure2D:: LoadMipLevel( nux::BaseTextur e*, int) () from libnux- graphics- 0.9.so. 0 ure2D:: CachedTexture2D (nux::NResource Set*, nux::Texture2D*) () from libnux- graphics- 0.9.so. 0 eFactory< nux::Texture2D, ure2D>: :BuildResource( nux::NResourceS et*, nux::ResourceData*) () libnux- graphics- 0.9.so. 0 ache::GetCached Resource( nux::ResourceDa ta*) () from libnux- graphics- 0.9.so. 0 gine::CacheReso urce(nux: :ResourceData* ) () from libnux- graphics- 0.9.so. 0 e::GetDeviceTex ture() () libnux- graphics- 0.9.so. 0 ::Refresh( ) () compiz/ libunityshell. so ::PanelHomeButt on() () compiz/ libunityshell. so :PanelView( char const*, int) () compiz/ libunityshell. so :initLauncher( nux::NThread* , void*) () compiz/ libunityshell. so :initUnity( nux::NThread* , void*) () compiz/ libunityshell. so ad::Run( void*) () libnux- 0.9.so. 0 :UnityScreen( CompScreen* ) () compiz/ libunityshell. so :VTableForScree nAndWindow< UnityScreen, UnityWindow> ::initScreen( CompScreen* ) compiz/ libunityshell. so :initPlugin( CompPlugin* ) () :push(CompPlugi n*) () :updatePlugins( ) () :processEvents( ) () ::callback( ) () :dispatch_ vfunc(_ GSource* , int (*)(void*), void*) () from libglibmm- 2.4.so. 1 context_ dispatch () from /lib/libglib- 2.0.so. 0 2.0.so. 0 context_ iteration () 2.0.so. 0 xt::iteration( bool) () libglibmm- 2.4.so. 1 :eventLoop( ) ()
#0 0x0000000000000000 in ?? ()
#1 0x00007fffeb58fcf0 in nux::IOpenGLSur
from /usr/lib/
#2 0x00007fffeb58798a in nux::IOpenGLTex
from /usr/lib/
#3 0x00007fffeb55a545 in nux::CachedText
/usr/lib/
#4 0x00007fffeb55ae2d in nux::CachedText
/usr/lib/
#5 0x00007fffeb557b54 in nux::TGLResourc
nux::CachedText
from /usr/lib/
#6 0x00007fffeb55736c in nux::NResourceC
/usr/lib/
#7 0x00007fffeb54c8cd in nux::GraphicsEn
/usr/lib/
#8 0x00007fffeb55a09f in nux::BaseTextur
from /usr/lib/
#9 0x00007fffebbbdfa1 in PanelHomeButton
from /usr/lib/
#10 0x00007fffebbbe371 in PanelHomeButton
from /usr/lib/
#11 0x00007fffebbc4b96 in PanelView:
from /usr/lib/
#12 0x00007fffebbde85c in UnityScreen:
from /usr/lib/
#13 0x00007fffebbdeabd in UnityScreen:
from /usr/lib/
#14 0x00007fffeb919282 in nux::WindowThre
from /usr/lib/
#15 0x00007fffebbdf57a in UnityScreen:
from /usr/lib/
#16 0x00007fffebbe1c49 in CompPlugin:
() from /usr/lib/
#17 0x00000000004501fa in CompManager:
#18 0x00000000004512fe in CompPlugin:
#19 0x000000000042d588 in PrivateScreen:
#20 0x000000000042d898 in PrivateScreen:
#21 0x000000000042d8f8 in CompEventSource
#22 0x00007ffff6e4440f in Glib::Source:
/usr/lib/
#23 0x00007ffff6956c4d in g_main_
#24 0x00007ffff6957438 in ?? () from /lib/libglib-
#25 0x00007ffff69576c9 in g_main_
from /lib/libglib-
#26 0x00007ffff6e452e3 in Glib::MainConte
from /usr/lib/
#27 0x000000000042932a in CompScreen:
#28 0x00000000004222e0 in main ()