(gdb) t a a bt

Thread 1 (Thread 0xb7cdf8d0 (LWP 18216)):
#0  VMWAREComposite (op=1 '\001', pSrc=0x8fe7b30, pMask=0x8fe7bc0, pDst=0x8fe7c38, xSrc=0, ySrc=0,
    xMask=0, yMask=0, xDst=0, yDst=0, width=32, height=32) at vmwarecurs.c:448
#1  0x08176e33 in damageComposite (op=0 '\0', pSrc=0x8fe7b30, pMask=0x8fe7bc0, pDst=0x8fe7c38,
    xSrc=<value optimized out>, ySrc=<value optimized out>, xMask=<value optimized out>,
    yMask=<value optimized out>, xDst=<value optimized out>, yDst=<value optimized out>,
    width=<value optimized out>, height=<value optimized out>) at damage.c:580
#2  0x0815fe0e in CompositePicture (op=1 '\001', pSrc=0x8fe7b30, pMask=0x8fe7bc0, pDst=0x8fe7c38,
    xSrc=<value optimized out>, ySrc=<value optimized out>, xMask=<value optimized out>,
    yMask=<value optimized out>, xDst=<value optimized out>, yDst=<value optimized out>,
    width=<value optimized out>, height=<value optimized out>) at picture.c:1758
#3  0x08165fad in ProcRenderComposite (client=0x8fd7d28) at render.c:758
#4  0x08162d85 in ProcRenderDispatch (client=0x0) at render.c:2002
#5  0x08156454 in XaceCatchExtProc (client=0x8fd7d28) at xace.c:299
#6  0x0808e03c in Dispatch () at dispatch.c:502
#7  0x08074255 in main (argc=6, argv=0xbf90ecf4, envp=Cannot access memory at address 0x8
) at main.c:452
(gdb)
#8  VMWAREComposite (op=1 '\001', pSrc=0x8fe7b30, pMask=0x8fe7bc0,
pDst=0x8fe7c38, xSrc=0, ySrc=0, xMask=0, yMask=0, xDst=0, yDst=0, width=32,
height=32) at vmwarecurs.c:448
448         box.x1 = pSrc->pDrawable->x + xSrc;
(gdb) p *pSrc
$1 = {pDrawable = 0x0, pFormat = 0x0, format = PICT_a8r8g8b8, refcnt = 1, id =
8388653, pNext = 0x0, repeat = 0, graphicsExposures = 0, subWindowMode = 0,
polyEdge = 0, polyMode = 0, freeCompClip = 0, clientClipType = 0,
componentAlpha = 0, repeatType = 0, unused = 0, alphaMap = 0x0, alphaOrigin =
{x = 0, y = 0}, clipOrigin = {x = 0, y = 0}, clientClip = 0x0, dither = 0,
stateChanges = 8191, serialNumber = 2147483648, pCompositeClip = 0x0,
devPrivates = 0x0, transform = 0x0, filter = 0, filter_params = 0x0,
filter_nparams = 0, pSourcePict = 0x8fe7b90}
(gdb)