I managed to create the attached backtrace by adding the -core option to GDM’s Xorg call and then using
$ gdb -c corefile /usr/bin/xorg (gdb) set logging on (gdb) bt full (gdb) quit Best regards, Claudius
#0 0x00007f3c7ab9e405 in *__GI_raise (sig=<optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 pid = <optimized out> selftid = <optimized out> #1 0x00007f3c7aba1680 in *__GI_abort () at abort.c:92 act = {__sigaction_handler = {sa_handler = 0x7f3c7ccedfd0, sa_sigaction = 0x7f3c7ccedfd0}, sa_mask = {__val = {52, 139897771117408, 139897768534885, 1, 139897366892672, 139897733589920, 139897766757600, 32256, 4294967295, 0, 1, 4108520, 0, 32256, 139897366924800, 139897766899712}}, sa_flags = 2089953090, sa_restorer = 0x7f3c00000001} sigs = {__val = {32, 0 <repeats 15 times>}} #2 0x00007f3c7ccc11fe in OsAbort () at ../../os/utils.c:1230 No locals. #3 0x00007f3c7cbc3e9c in ddxGiveUp (error=EXIT_ERR_ABORT) at ../../../../hw/xfree86/common/xf86Init.c:936 i = <optimized out> #4 0x00007f3c7ccc60b2 in AbortServer () at ../../os/log.c:416 No locals. #5 0x00007f3c7ccc62b5 in FatalError (f=0x7f3c7ccebed0 "Caught signal %d (%s). Server aborting\n") at ../../os/log.c:547 args = {{gp_offset = 24, fp_offset = 48, overflow_arg_area = 0x7fff34c3a820, reg_save_area = 0x7fff34c3a760}} beenhere = 1 #6 0x00007f3c7ccbf12e in OsSigHandler (sip=<optimized out>, signo=7, unused=<optimized out>) at ../../os/osinit.c:146 No locals. #7 OsSigHandler (signo=7, sip=<optimized out>, unused=<optimized out>) at ../../os/osinit.c:108 No locals. #8 <signal handler called> No symbol table info available. #9 __memcpy_ssse3_back () at ../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:820 No locals. #10 0x00007f3c789687f6 in intel_uxa_pixmap_put_image (pixmap=<optimized out>, src=<optimized out>, src_pitch=32000, x=<optimized out>, y=<optimized out>, w=<optimized out>, h=8) at ../../src/intel_uxa.c:752 dst = <optimized out> row_length = 32000 num_rows = 8 priv = 0x7f3c7faa4970 stride = 32256 cpp = <optimized out> ret = 0 #11 0x00007f3c7896a4a7 in intel_uxa_put_image (pixmap=0x7f3c7faa62b0, x=0, y=0, w=<optimized out>, h=8, src=0x7f3c7faf1f28 "", src_pitch=32000) at ../../src/intel_uxa.c:809 intel = 0x7f3c7acbaa50 tiling = 0 size = <optimized out> stride = 2 bo = <optimized out> screen = <optimized out> priv = 0x7f3c7faa4970 #12 0x00007f3c7898a8d4 in uxa_do_put_image (src_stride=32000, bits=0x7f3c7faf1f28 "", format=2, h=8, w=8000, y=<optimized out>, x=<optimized out>, pGC=0x7f3c7faa5ae0, pDrawable=0x7f3c7faa62b0, depth=<optimized out>) at ../../uxa/uxa-accel.c:164 y1 = 0 x2 = <optimized out> ok = <optimized out> x1 = 0 y2 = <optimized out> src = 0x7f3c7faf1f28 "" yoff = 0 uxa_screen = 0x0 pPix = 0x7f3c7faa62b0 pClip = <optimized out> pbox = 0x7f3c7faa57c0 nbox = <optimized out> xoff = 0 bpp = <optimized out> #13 uxa_put_image (pDrawable=0x7f3c7faa62b0, pGC=0x7f3c7faa5ae0, depth=<optimized out>, x=0, y=0, w=8000, h=8, leftPad=0, format=2, bits=0x7f3c7faf1f28 "") at ../../uxa/uxa-accel.c:202 No locals. #14 0x00007f3c7cc4f3fc in damagePutImage (pDrawable=0x7f3c7faa62b0, pGC=0x7f3c7faa5ae0, depth=24, x=0, y=0, w=8000, h=8, leftPad=0, format=2, pImage=0x7f3c7faf1f28 "") at ../../../miext/damage/damage.c:830 pGCPriv = 0x7f3c7faa5ba8 oldFuncs = 0x7f3c7cf2b3e0 #15 0x00007f3c7cb85c1e in ProcPutImage (client=<optimized out>) at ../../dix/dispatch.c:1989 pGC = 0x7f3c7faa5ae0 pDraw = 0x7f3c7faa62b0 length = <optimized out> lengthProto = <optimized out> tmpImage = 0x7f3c7faf1f28 "" stuff = 0x7f3c7faf1f10 #16 0x00007f3c7cb88f81 in Dispatch () at ../../dix/dispatch.c:437 clientReady = 0x7f3c7f8c5730 result = <optimized out> client = 0x7f3c7fa60130 nready = 0 icheck = 0x7f3c7cf3dad0 start_tick = 1860 #17 0x00007f3c7cb781aa in main (argc=11, argv=<optimized out>, envp=<optimized out>) at ../../dix/main.c:287 i = <optimized out> alwaysCheckForInput = {0, 1}