Application: kwin (4.10.5)
KDE Platform Version: 4.10.5
Qt Version: 4.8.2
Operating System: Linux 3.9.0-custom x86_64
Distribution: Ubuntu 12.04.2 LTS

-- Information about the crash:
- What I was doing when the application crashed:

Recently, the screensaver has gone blank sometimes when it is enabled.  Unclear, when exactly that happens.  The same sometimes happens for full-screen video applications, for example flash player.  Killing the bad application (screensaver) then sometimes crashes kwin, too, with the attached backtrace.  I know that there are many related bugs, but I am on a fairly (3.9.0) recent kernel and X-driver (2:2.21.12~precise~ppa1 via http://ppa.launchpad.net/glasen/intel-driver/ubuntu/)

- Unusual behavior I noticed:

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f9480b047c0 (LWP 17054))]

Thread 3 (Thread 0x7f9457fff700 (LWP 17069)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f947cc19022 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f947cc19059 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f9474639e9a in start_thread (arg=0x7f9457fff700) at pthread_create.c:308
#4  0x00007f9480357ccd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f945ffff700 (LWP 19790)):
#0  0x00007f9480351033 in select () at ../sysdeps/unix/syscall-template.S:82
#1  0x00007f947b73f866 in qt_safe_select (nfds=19, fdread=0x7f9458000ac8, fdwrite=0x7f9458000d60, fdexcept=0x7f9458000ff8, orig_timeout=<optimized out>) at kernel/qcore_unix.cpp:83
#2  0x00007f947b744cb2 in QEventDispatcherUNIXPrivate::doSelect (this=0x7f9458000910, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:223
#3  0x00007f947b7451a3 in QEventDispatcherUNIX::processEvents (this=0x7f94580008f0, flags=...) at kernel/qeventdispatcher_unix.cpp:926
#4  0x00007f947b711e62 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f947b7120b7 in QEventLoop::exec (this=0x7f945fffed90, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f947b611077 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007f947b6f1b6f in QInotifyFileSystemWatcherEngine::run (this=0x36732a0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f947b61409b in QThreadPrivate::start (arg=0x36732a0) at thread/qthread_unix.cpp:307
#9  0x00007f9474639e9a in start_thread (arg=0x7f945ffff700) at pthread_create.c:308
#10 0x00007f9480357ccd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f9480b047c0 (LWP 17054)):
[KCrash Handler]
#6  brw_update_renderbuffer_surface (brw=0x385c520, rb=0x25e1900, unit=0) at brw_wm_surface_state.c:1165
#7  0x00007f945eb82ab0 in brw_update_renderbuffer_surfaces (brw=0x385c520) at brw_wm_surface_state.c:1261
#8  0x00007f945eb6bc42 in brw_upload_state (brw=0x385c520) at brw_state_upload.c:500
#9  0x00007f945eb589f7 in brw_try_draw_prims (max_index=<optimized out>, min_index=<optimized out>, ib=0x7fff949b5058, nr_prims=59152552, prim=0x7fff949b5040, arrays=<optimized out>, ctx=0x385c520) at brw_draw.c:493
#10 brw_draw_prims (ctx=0x385c520, prim=0x7fff949b5040, nr_prims=59152552, ib=0x7fff949b5058, index_bounds_valid=<optimized out>, min_index=0, max_index=3, tfb_vertcount=0x0) at brw_draw.c:589
#11 0x00007f945e6d3699 in vbo_draw_arrays (ctx=0x385c520, mode=6, start=0, count=<optimized out>, numInstances=1, baseInstance=<optimized out>) at ../../../../../src/mesa/vbo/vbo_exec_array.c:645
#12 0x00007f945e77aabf in _mesa_meta_glsl_Clear (ctx=0x385c520, buffers=<optimized out>) at ../../../../../src/mesa/drivers/common/meta.c:2091
#13 0x00007f945eb4c2c4 in brw_clear (mask=0, ctx=0x385c520) at brw_clear.c:239
#14 brw_clear (ctx=0x385c520, mask=<optimized out>) at brw_clear.c:208
#15 0x00007f94806f1341 in KWin::SceneOpenGL::paintBackground (this=0x2675d00, region=...) at ../../kwin/scene_opengl.cpp:349
#16 0x00007f94806e2289 in KWin::Scene::paintScreen (this=0x2675d00, mask=0x7fff949b53c8, region=0x7fff949b5510) at ../../kwin/scene.cpp:137
#17 0x00007f94806f5f33 in KWin::SceneOpenGL::paint (this=0x2675d00, damage=..., toplevels=...) at ../../kwin/scene_opengl.cpp:308
#18 0x00007f94806da9c9 in performCompositing (this=0x25decd0) at ../../kwin/composite.cpp:610
#19 KWin::Compositor::performCompositing (this=0x25decd0) at ../../kwin/composite.cpp:541
#20 0x00007f947b72c679 in QObject::event (this=0x25decd0, e=<optimized out>) at kernel/qobject.cpp:1157
#21 0x00007f947aa947b4 in notify_helper (e=0x7fff949b5bd0, receiver=0x25decd0, this=0x24abc90) at kernel/qapplication.cpp:4556
#22 QApplicationPrivate::notify_helper (this=0x24abc90, receiver=0x25decd0, e=0x7fff949b5bd0) at kernel/qapplication.cpp:4528
#23 0x00007f947aa99583 in QApplication::notify (this=0x7fff949b5fb0, receiver=0x25decd0, e=0x7fff949b5bd0) at kernel/qapplication.cpp:4417
#24 0x00007f947fe316b6 in KApplication::notify (this=0x7fff949b5fb0, receiver=0x25decd0, event=0x7fff949b5bd0) at ../../kdeui/kernel/kapplication.cpp:311
#25 0x00007f947b71332c in QCoreApplication::notifyInternal (this=0x7fff949b5fb0, receiver=0x25decd0, event=0x7fff949b5bd0) at kernel/qcoreapplication.cpp:915
#26 0x00007f947b7446f2 in sendEvent (event=0x7fff949b5bd0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#27 QTimerInfoList::activateTimers (this=0x24ac848) at kernel/qeventdispatcher_unix.cpp:611
#28 0x00007f947b7451b4 in QEventDispatcherUNIX::processEvents (this=0x244d2c0, flags=...) at kernel/qeventdispatcher_unix.cpp:930
#29 0x00007f947ab3db78 in QEventDispatcherX11::processEvents (this=0x244d2c0, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#30 0x00007f947b711e62 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#31 0x00007f947b7120b7 in QEventLoop::exec (this=0x7fff949b5f30, flags=...) at kernel/qeventloop.cpp:204
#32 0x00007f947b717407 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187
#33 0x00007f948068c05b in kdemain (argc=<optimized out>, argv=<optimized out>) at ../../kwin/main.cpp:537
#34 0x00007f948028576d in __libc_start_main (main=0x400640 <main(int, char**)>, argc=3, ubp_av=0x7fff949b66a8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff949b6698) at libc-start.c:226
#35 0x0000000000400671 in _start ()

Possible duplicates by query: bug 322487, bug 321352, bug 320624, bug 319758, bug 319007.

Reported using DrKonqi