GNU gdb (GDB) 7.5 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-unknown-linux-gnu". For bug reporting instructions, please see: ... Reading symbols from /usr/bin/X...done. [?1034h(gdb) r Starting program: /usr/bin/X :8 -config /etc/bumblebee/xorg.conf.radeon -sharevts -nolisten tcp -noreset -isolateDevice PCI:01:00:00 [Thread debugging using libthread_db enabled] Using host libthread_db library "/usr/lib/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x00000000004cbbe0 in SetCompatOutput (config=0x151a290) at xf86Crtc.c:1829 1829 output = config->output[config->compat_output]; (gdb) bt #0 0x00000000004cbbe0 in SetCompatOutput (config=0x151a290) at xf86Crtc.c:1829 #1 0x00000000004cbc31 in xf86SetScrnInfoModes (scrn=0x15137b0) at xf86Crtc.c:1843 #2 0x00000000004cd9f8 in xf86InitialConfiguration (scrn=0x15137b0, canGrow=1) at xf86Crtc.c:2503 #3 0x00007f2a07825f33 in drmmode_pre_init (pScrn=pScrn@entry=0x15137b0, drmmode=drmmode@entry=0x1518ad0, cpp=) at drmmode_display.c:1516 #4 0x00007f2a078222d4 in RADEONPreInit_KMS (pScrn=0x15137b0, flags=) at radeon_kms.c:739 #5 0x00000000004900c8 in InitOutput (pScreenInfo=0x866ec0 , argc=10, argv=0x7fff255b7d58) at xf86Init.c:586 #6 0x00000000004219d9 in main (argc=10, argv=0x7fff255b7d58, envp=0x7fff255b7db0) at main.c:203 (gdb) c Continuing. Program received signal SIGABRT, Aborted. 0x00007f2a08b97fa5 in raise () from /usr/lib/libc.so.6 (gdb) q A debugging session is active. Inferior 1 [process 10341] will be killed. Quit anyway? (y or n)