(gdb) bt
#0  0x00007fdfd3190835 in _int_malloc () from /lib64/libc.so.6
#1  0x00007fdfd3192b39 in malloc () from /lib64/libc.so.6
#2  0x00007fdfd06dbef4 in exaPrepareAccessReg_mixed (pPixmap=0x1f68ad0, 
    index=0, pReg=0x0) at exa_migration_mixed.c:203
#3  0x00007fdfd06e7293 in ExaPrepareCompositeReg (op=3 '\003', pSrc=0x1fbaec0, 
    pMask=0x1fbafc0, pDst=0x1fba930, xSrc=920, ySrc=54, xMask=0, yMask=0, 
    xDst=920, yDst=54, width=93, height=35) at exa_unaccel.c:599
#4  ExaCheckComposite (op=3 '\003', pSrc=0x1fbaec0, pMask=0x1fbafc0, 
    pDst=0x1fba930, xSrc=920, ySrc=54, xMask=0, yMask=0, xDst=920, yDst=54, 
    width=93, height=35) at exa_unaccel.c:624
#5  0x00007fdfd06e31fb in exaComposite (op=3 '\003', pSrc=0x1fbaec0, 
    pMask=0x1fbafc0, pDst=0x1fba930, xSrc=<value optimized out>, 
    ySrc=<value optimized out>, xMask=0, yMask=0, xDst=<value optimized out>, 
    yDst=<value optimized out>, width=93, height=35) at exa_render.c:1066
#6  0x00000000004db66c in damageComposite (op=3 '\003', pSrc=0x1fbaec0, 
    pMask=0x1fbafc0, pDst=0x1fba930, xSrc=920, ySrc=54, xMask=0, yMask=0, 
    xDst=920, yDst=54, width=93, height=35) at damage.c:640
#7  0x00000000004cec79 in ProcRenderComposite (client=<value optimized out>)
    at render.c:723
#8  0x000000000044b6f1 in Dispatch () at dispatch.c:432
#9  0x0000000000425b5e in main (argc=9, argv=<value optimized out>, 
    envp=<value optimized out>) at main.c:291