I have exactly the same problem since upgrading to 15.10. For me reproducable in LibreOffice 5.0.3.2 Calc by a right mouse click followed by selecting "Format Cells...".
Xorg.0.log.old: [ 674.409] (EE) Backtrace: [ 674.409] (EE) 0: /usr/bin/X (xorg_backtrace+0x4e) [0x55d163d7262e] [ 674.409] (EE) 1: /usr/bin/X (0x55d163bbe000+0x1b8999) [0x55d163d76999] [ 674.409] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f82b6c33000+0x352f0) [0x7f82b6c682f0] [ 674.409] (EE) 3: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x24f18) [0x7f82b302ef18] [ 674.409] (EE) 4: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x26157) [0x7f82b3030157] [ 674.409] (EE) 5: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x2b4b1) [0x7f82b30354b1] [ 674.409] (EE) 6: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x804e4) [0x7f82b308a4e4] [ 674.409] (EE) 7: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x80e2c) [0x7f82b308ae2c] [ 674.409] (EE) 8: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x82e1a) [0x7f82b308ce1a] [ 674.409] (EE) 9: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x4197c) [0x7f82b304b97c] [ 674.409] (EE) 10: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f82b300a000+0x59906) [0x7f82b3063906] [ 674.409] (EE) 11: /usr/bin/X (_CallCallbacks+0x34) [0x55d163c1b654] [ 674.409] (EE) 12: /usr/bin/X (WriteToClient+0x244) [0x55d163d76274] [ 674.409] (EE) 13: /usr/bin/X (WriteEventsToClient+0x1e2) [0x55d163c21502] [ 674.409] (EE) 14: /usr/bin/X (0x55d163bbe000+0xf495a) [0x55d163cb295a] [ 674.409] (EE) 15: /usr/bin/X (0x55d163bbe000+0xf5ef5) [0x55d163cb3ef5] [ 674.409] (EE) 16: /usr/bin/X (0x55d163bbe000+0x5818f) [0x55d163c1618f] [ 674.409] (EE) 17: /usr/bin/X (0x55d163bbe000+0x5c34b) [0x55d163c1a34b] [ 674.409] (EE) 18: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f82b6c53a40] [ 674.409] (EE) 19: /usr/bin/X (_start+0x29) [0x55d163c046c9] [ 674.409] (EE) [ 674.409] (EE) Segmentation fault at address 0x0 [ 674.409] (EE) Fatal server error: [ 674.409] (EE) Caught signal 11 (Segmentation fault). Server aborting -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1510998 Title: Xorg crashes with segfault on 15.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1510998/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs