[compiz] Crash unloading blur

[Mike Dransfield]

I am getting this crash when unloading compiz by starting
kwin.  It seems fairly easy to reproduce here.

I am using nvidia 9755 drivers

(gdb) bt
#0  0x00002b9b20e688b0 in write () from /lib/libc.so.6
#1  0x00002b9b2088c7bf in ?? () from /usr/lib/libX11.so.6
#2  0x00002b9b208842f9 in ?? () from /usr/lib/libX11.so.6
#3  0x00002b9b2088438e in _XReply () from /usr/lib/libX11.so.6
#4  0x00002b9b206f5ae2 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGL.so.1
#5  0x00002b9b206d008a in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGL.so.1
#6  0x00002b9b206f1a04 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGL.so.1
#7  0x00002b9b2148829d in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#8  0x00002b9b21487715 in _nv000122gl () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#9  0x00002b9b21425920 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#10 0x00002b9b21425705 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#11 0x00002b9b2146c1ba in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#12 0x00002b9b2148c39c in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#13 0x00002b9b2148ff86 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#14 0x00002b9b21489617 in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#15 0x00002b9b211db69c in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#16 0x00002b9b21187f9f in _nv000534gl () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#17 0x00002b9b211da1ac in ?? () from 
//usr/lib64/opengl/nvidia/lib/libGLcore.so.1
#18 0x00002aaaaf5038c2 in blurFiniScreen (p=0x7, s=0x547800) at blur.c:2765
#19 0x00000000004251ac in finiPluginForDisplay (p=0x76ca30, d=0x532f60) 
at plugin.c:217
#20 0x00000000004259a7 in popPlugin () at plugin.c:320
#21 0x000000000040c445 in eventLoop () at display.c:2062
#22 0x000000000040a0d8 in main (argc=3, argv=0x7fff8b2db358) at main.c:260