(gdb) bt
#0  __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:97
#1  0x00007fcd43fcc80f in _L_lock_12013 () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007fcd43fca8d8 in __libc_free (mem=0x7fcd442dd1c0) at malloc.c:3736
#3  0x00000000004a3a12 in _XSERVTransFreeConnInfo (ciptr=0x1405f40) at /usr/include/X11/Xtrans/Xtrans.c:138
#4  0x00000000004a3ef4 in _XSERVTransClose (ciptr=0x1405f40) at /usr/include/X11/Xtrans/Xtrans.c:930
#5  0x0000000000461f1f in CloseWellKnownConnections () at ../../os/connection.c:493
#6  0x000000000045e598 in SigAbortServer (signo=11) at ../../os/log.c:409
#7  0x000000000045f1d2 in FatalSignal (signo=11) at ../../os/log.c:541
#8  <signal handler called>
#9  _int_malloc (av=0x7fcd442dd1c0, bytes=<value optimized out>) at malloc.c:4709
#10 0x00007fcd43fca31e in __libc_malloc (bytes=3921632) at malloc.c:3660
#11 0x00007fcd41b43b44 in exaPrepareAccessReg_mixed (pPixmap=0x30a6420, index=0, pReg=0x0)
    at ../../exa/exa_migration_mixed.c:203
#12 0x00007fcd41b4c67f in ExaFallbackPrepareReg (pDrawable=0x30a2740, pGC=<value optimized out>, x=4, y=4, 
    width=<value optimized out>, height=<value optimized out>, index=0, checkReads=1) at ../../exa/exa_unaccel.c:195
#13 0x00007fcd41b4d7e8 in ExaCheckCopyPlane (pSrc=0x30a23b0, pDst=0x30a2740, pGC=0x16e7e70, srcx=<value optimized out>, 
    srcy=<value optimized out>, w=1, h=16, dstx=4, dsty=4, bitPlane=1) at ../../exa/exa_unaccel.c:232
#14 0x00000000004e0d10 in damageCopyPlane (pSrc=0x30a23b0, pDst=0x30a2740, pGC=0x16e7e70, srcx=0, srcy=0, width=1, height=16, 
    dstx=4, dsty=4, bitPlane=1) at ../../../miext/damage/damage.c:948
#15 0x00000000004243b3 in ProcCopyPlane (client=0x305add0) at ../../dix/dispatch.c:1694
#16 0x0000000000428259 in Dispatch () at ../../dix/dispatch.c:431
#17 0x0000000000421a7e in main (argc=8, argv=<value optimized out>, envp=<value optimized out>) at ../../dix/main.c:287
(gdb) bt full
#0  __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:97
No locals.
#1  0x00007fcd43fcc80f in _L_lock_12013 () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#2  0x00007fcd43fca8d8 in __libc_free (mem=0x7fcd442dd1c0) at malloc.c:3736
        ar_ptr = 0x7fcd442dd1c0
        p = 0x1405f90
        hook = <value optimized out>
#3  0x00000000004a3a12 in _XSERVTransFreeConnInfo (ciptr=0x1405f40) at /usr/include/X11/Xtrans/Xtrans.c:138
No locals.
#4  0x00000000004a3ef4 in _XSERVTransClose (ciptr=0x1405f40) at /usr/include/X11/Xtrans/Xtrans.c:930
        ret = 0
#5  0x0000000000461f1f in CloseWellKnownConnections () at ../../os/connection.c:493
        i = <value optimized out>
#6  0x000000000045e598 in SigAbortServer (signo=11) at ../../os/log.c:409
No locals.
#7  0x000000000045f1d2 in FatalSignal (signo=11) at ../../os/log.c:541
        beenhere = 1
#8  <signal handler called>
No symbol table info available.
#9  _int_malloc (av=0x7fcd442dd1c0, bytes=<value optimized out>) at malloc.c:4709
        p = <value optimized out>
        iters = <value optimized out>
        nb = 3921648
        idx = 127
        bin = 0x7fcd442dd9f8
        victim = 0x3893190
        size = <value optimized out>
        victim_index = <value optimized out>
        remainder = 0x3c50880
        remainder_size = <value optimized out>
        block = <value optimized out>
        bit = <value optimized out>
        map = 805306368
        fwd = <value optimized out>
        bck = <value optimized out>
        errstr = 0x0
        __func__ = "_int_malloc"
#10 0x00007fcd43fca31e in __libc_malloc (bytes=3921632) at malloc.c:3660
        ar_ptr = 0x7fcd442dd1c0
        victim = <value optimized out>
        hook = <value optimized out>
        __func__ = "__libc_malloc"
#11 0x00007fcd41b43b44 in exaPrepareAccessReg_mixed (pPixmap=0x30a6420, index=0, pReg=0x0)
    at ../../exa/exa_migration_mixed.c:203
        pixmaps = {{as_dst = 0, as_src = 1, pPix = 0x30a23b0, pReg = 0x7fff0770ac90}}
        pExaPixmap = 0x30a6470
        has_gpu_copy = <value optimized out>
        success = <value optimized out>
#12 0x00007fcd41b4c67f in ExaFallbackPrepareReg (pDrawable=0x30a2740, pGC=<value optimized out>, x=4, y=4, 
    width=<value optimized out>, height=<value optimized out>, index=0, checkReads=1) at ../../exa/exa_unaccel.c:195
        pScreen = <value optimized out>
        pExaScr = 0x1435e90
#13 0x00007fcd41b4d7e8 in ExaCheckCopyPlane (pSrc=0x30a23b0, pDst=0x30a2740, pGC=0x16e7e70, srcx=<value optimized out>, 
    srcy=<value optimized out>, w=1, h=16, dstx=4, dsty=4, bitPlane=1) at ../../exa/exa_unaccel.c:232
        ret = <value optimized out>
        pExaScr = 0x1435e90
        pExaGC = 0x16e7f38
#14 0x00000000004e0d10 in damageCopyPlane (pSrc=0x30a23b0, pDst=0x30a2740, pGC=0x16e7e70, srcx=0, srcy=0, width=1, height=16, 
    dstx=4, dsty=4, bitPlane=1) at ../../../miext/damage/damage.c:948
        ret = <value optimized out>
        pGCPriv = 0x16e7f48
        oldFuncs = 0x7dfbc0
#15 0x00000000004243b3 in ProcCopyPlane (client=0x305add0) at ../../dix/dispatch.c:1694
        psrcDraw = 0x30a23b0
        pdstDraw = 0x30a2740
        pGC = 0x16e7e70
        stuff = 0x307c520
        pRgn = <value optimized out>
        rc = <value optimized out>
#16 0x0000000000428259 in Dispatch () at ../../dix/dispatch.c:431
        clientReady = 0x169bda0
        result = <value optimized out>
        client = 0x305add0
        nready = 0
        icheck = 0x7f1290
        start_tick = 1240
#17 0x0000000000421a7e in main (argc=8, argv=<value optimized out>, envp=<value optimized out>) at ../../dix/main.c:287
        i = <value optimized out>
        alwaysCheckForInput = {0, 1}