bug#12251: 24.2.50; crash in note_mouse_highlight

[Sam Steingold <sds@gnu.org>]

In GNU Emacs 24.2.50.3 (x86_64-unknown-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2012-08-20 on t520sds
Bzr revision: 109703 rgm@gnu.org-20120820181303-1o7qqwvj2z4q4cuu
Windowing system distributor `The X.Org Foundation', version 11.0.11103000
Configured using:
 `configure '--with-wide-int''

emacs just crashed for me:

Program received signal SIGSEGV, Segmentation fault.
note_mouse_highlight (f=0x1175580, x=298, y=1012) at /home/sds/src/emacs/trunk/src/xdisp.c:27710
27710         && w->last_modified == BUF_MODIFF (b)
(gdb) xbacktrace
(gdb) backtrace
#0  note_mouse_highlight (f=0x1175580, x=298, y=1012) at /home/sds/src/emacs/trunk/src/xdisp.c:27710
#1  0x00000000004b7668 in note_mouse_movement (frame=0x1175580, event=0x7fffffffc8a0) at /home/sds/src/emacs/trunk/src/xterm.c:3858
#2  0x00000000004c0101 in handle_one_xevent (dpyinfo=0x1336c10, eventptr=0x7fffffffc9c0, finish=0x7fffffffc9bc,
    hold_quit=0x7fffffffcd50) at /home/sds/src/emacs/trunk/src/xterm.c:6801
#3  0x00000000004c18b6 in XTread_socket (terminal=0xfc4d28, expected=<optimized out>, hold_quit=0x7fffffffcd50)
    at /home/sds/src/emacs/trunk/src/xterm.c:7185
#4  0x00000000004f91b7 in read_avail_input (expected=1) at /home/sds/src/emacs/trunk/src/keyboard.c:6897
#5  0x00000000004f92da in handle_async_input () at /home/sds/src/emacs/trunk/src/keyboard.c:7226
#6  0x00000000004b9ac5 in XTring_bell (f=<optimized out>) at /home/sds/src/emacs/trunk/src/xterm.c:3259
#7  XTring_bell (f=0x1175580) at /home/sds/src/emacs/trunk/src/xterm.c:3248
#8  0x00000000004f5da5 in cmd_error_internal (data=68832822, context=0x7fffffffcf30 "")
    at /home/sds/src/emacs/trunk/src/keyboard.c:1147
#9  0x00000000004f5f23 in cmd_error (data=68832822) at /home/sds/src/emacs/trunk/src/keyboard.c:1080
#10 0x0000000000567fe9 in internal_condition_case (bfun=0x501430 <command_loop_1>, handlers=12043794, hfun=0x4f5e10 <cmd_error>)
    at /home/sds/src/emacs/trunk/src/eval.c:1312
#11 0x00000000004f3e6e in command_loop_2 (ignore=<optimized out>) at /home/sds/src/emacs/trunk/src/keyboard.c:1204
#12 0x0000000000567e98 in internal_catch (tag=11992018, func=0x4f3e50 <command_loop_2>, arg=11992018)
    at /home/sds/src/emacs/trunk/src/eval.c:1079
#13 0x00000000004f58d7 in command_loop () at /home/sds/src/emacs/trunk/src/keyboard.c:1183
#14 recursive_edit_1 () at /home/sds/src/emacs/trunk/src/keyboard.c:804
#15 0x00000000004f5c14 in Frecursive_edit () at /home/sds/src/emacs/trunk/src/keyboard.c:868
#16 0x000000000040fffd in main (argc=1, argv=<optimized out>) at /home/sds/src/emacs/trunk/src/emacs.c:1662
(gdb) xbacktrace
(gdb) p b
$1 = (struct buffer *) 0xb6fbcd
(gdb) p *b
$2 = {
  header = {
    size = 6845104128,
    next = {
      nbytes = 144868458364928,
      buffer = 0x83c1d1000000,
      vector = 0x83c1d1000000
    } 
  },
  name_ = 201192676261888,
  filename_ = 201191870955520,
  directory_ = 1019673118244864,
  backed_up_ = 0,
  save_length_ = 2550136832,
  auto_save_file_name_ = 144868995235840,
  read_only_ = 201193481568256,
  mark_ = 201191870955520,
  local_var_alist_ = 267594548379648,
  major_mode_ = 0,
  mode_name_ = 2281701376,
  mode_line_format_ = 144869532106752,
  header_line_format_ = 201191870955520,
  keymap_ = 201191870955520,
  abbrev_table_ = 201192676261888,
  syntax_table_ = 0,
  category_table_ = 2281701376,
  case_fold_search_ = 144870068977664,
  tab_width_ = 201191870955520,
  fill_column_ = 190696363393024,
  left_margin_ = 200854514696192,
  auto_fill_function_ = 0,
  downcase_table_ = 2281701376,
  upcase_table_ = 144870605848576,
  case_canon_table_ = 201191870955520,
  case_eqv_table_ = 201191870955520,
  truncate_lines_ = 201192676261888,
  word_wrap_ = 0,
  ctl_arrow_ = 2281701376,
  bidi_display_reordering_ = 144871142719488,
  bidi_paragraph_direction_ = 201191870955520,
  selective_display_ = 144450437251072,
  selective_display_ellipses_ = 200857199050752,
  minor_modes_ = 0,
  overwrite_mode_ = 2281701376,
  abbrev_mode_ = 144871679590400,
  display_table_ = 201191870955520,
  mark_active_ = 201191870955520,
  enable_multibyte_characters_ = 200857735921664,
  buffer_file_coding_system_ = 0,
  file_format_ = 2281701376,
  auto_save_file_format_ = 144873290203136,
  cache_long_line_scans_ = 201191870955520,
  width_table_ = 159832728403968,
  pt_marker_ = 201192676261888,
  begv_marker_ = 0,
  zv_marker_ = 2281701376,
  point_before_scroll_ = 144873827074048,
  file_truename_ = 201191870955520,
  invisibility_spec_ = 201191870955520,
  last_selected_window_ = 201192676261888,
  display_count_ = 0,
  left_margin_cols_ = 2281701376,
  right_margin_cols_ = 144874363944960,
  left_fringe_width_ = 201191870955520,
  right_fringe_width_ = 201191870955520,
  fringes_outside_margins_ = 200727813160960,
  scroll_bar_width_ = 0,
  vertical_scroll_bar_type_ = 2281701376,
  indicate_empty_lines_ = 144874900815872,
  indicate_buffer_boundaries_ = 201191870955520,
  fringe_indicator_alist_ = 201191870955520,
  fringe_cursor_alist_ = 201192676261888,
  display_time_ = 0,
  scroll_up_aggressively_ = 6509559808,
  scroll_down_aggressively_ = 144875437686784,
  cursor_type_ = 979353743654912,
  extra_line_spacing_ = 201191870955520,
  cursor_in_non_selected_windows_ = 200858272792576,
  own_text = {
    beg = 0x0,
    gpt = 2281701376,
    z = 144877048299520,
    gpt_byte = 201191870955520,
    z_byte = 201191870955520,
    gap_size = 256685063012352,
    modiff = 0,
    chars_modiff = 2281701376,
    save_modiff = 144877585170432,
    overlay_modiff = 201191870955520,
    compact = 201191870955520,
    beg_unchanged = 201192676261888,
    end_unchanged = 0,
    unchanged_modified = 2281701376,
    overlay_unchanged_modified = 144878122041344,
    intervals = 0xb6fba2000000,
    markers = 0x836f15000000,
    inhibit_shrinking = -771751936
  },
  text = 0x0,
  pt = 2281701376,
  pt_byte = 144878658912256,
  begv = 201191870955520,
  begv_byte = 164619201019904,
  zv = 201192676261888,
  zv_byte = 0,
  base_buffer = 0x98000000,
  indirections = 1358954496,
  local_flags = "ă\000\000\000\000\000\322\376\266\000\000\000\000\000\242\373\266\000\000\000\000\000\322\373\266", '\000' <repeats 13 times>"\230, \000\000\000\000\000\000\000qă",
  modtime = {
    tv_sec = 201206366470144,
    tv_nsec = 201191870955520
  },
  modtime_size = 201192676261888,
  auto_save_modified = 0,
  display_error_modiff = 2550136832,
  auto_save_failure_time = 144880269524992,
  last_window_start = 201207171776512,
  newline_cache = 0xb6fba2000000,
  width_run_cache = 0xb6fbd2000000,
  prevent_redisplay_optimizations_p = 0,
  clip_changed = 0,
  overlays_before = 0x98000000,
  overlays_after = 0x83c4b1000000,
  overlay_center = 201207977082880,
  undo_list_ = 201191870955520
}
(gdb) p w
$3 = (struct window *) 0x47ab190
(gdb) p *w
$4 = {
  header = {
    size = 4611686018427650087,
    next = {
      nbytes = 480,
      buffer = 0x1e0,
      vector = 0x1e0
    }
  },
  frame = 18306437,
  next = 18314661,
  prev = 11992018,
  hchild = 11992018,
  vchild = 11992018,
  parent = 11992018,
  left_col = 0,
  top_line = 0,
  total_lines = 11992018,
  total_cols = 796,
  normal_lines = 11968239,
  normal_cols = 11968231,
  new_total = 796,
  new_normal = 11992018,
  buffer = 11992018,
  start = 11992018,
  pointm = 11992018,
  temslot = 0,
  vertical_scroll_bar = 46806189,
  left_margin_cols = 11992018,
  right_margin_cols = 11992018,
  left_fringe_width = 11992018,
  right_fringe_width = 11992018,
  scroll_bar_width = 40,
  vertical_scroll_bar_type = 11992066,
  window_end_pos = 0,
  window_end_vpos = 0,
  window_end_valid = 11992018,
  display_table = 11992018,
  dedicated = 11992018,
  base_line_number = 4,
  base_line_pos = 4,
  region_showing = 11992018,
  column_number_displayed = 260,
  redisplay_end_trigger = 11992018,
  combination_limit = 11992018,
  prev_buffers = 41307798,
  next_buffers = 11992018,
  window_parameters = 11992018,
  current_matrix = 0x0,
  desired_matrix = 0x0,
  use_time = 3650,
  sequence_number = 139,
  hscroll = 0,
  min_hscroll = 0,
  last_modified = 0,
  last_overlay_modified = 0,
  last_point = 2630,
  nrows_scale_factor = 1,
  ncols_scale_factor = 1,
  last_cursor = {
    x = 0,
    y = 0,
    hpos = 0,
    vpos = 0
  },
  cursor = {
    x = 0,
    y = 0,
    hpos = 0,
    vpos = 0
  },
  phys_cursor = {
    x = 0,
    y = 0,
    hpos = 0,
    vpos = 0
  },
  phys_cursor_type = -1,
  phys_cursor_width = -1,
  phys_cursor_ascent = 11,
  phys_cursor_height = 13,
  mini = 0,
  update_mode_line = 0,
  last_had_star = 0,
  start_at_line_beg = 1,
  force_start = 0,
  optional_new_start = 0,
  phys_cursor_on_p = 1,
  cursor_off_p = 0,
  last_cursor_off_p = 0,
  must_be_updated_p = 0,
  pseudo_window_p = 0,
  frozen_window_start_p = 0,
  fringes_outside_margins = 0,
  vscroll = 0,
  window_end_bytepos = 4504
}


(gdb) generate-core-file
warning: Memory read failed for corefile section, 1048576 bytes at 0x7fffeb3f5000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7fffeb5fe000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff090b000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff0b11000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff0d1b000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff0f26000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff113f000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff134a000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff1557000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff1a27000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff1c2d000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff1e30000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff2042000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff22bd000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff24d1000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff26f9000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff2938000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff2b40000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff2d59000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff2f7a000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff317f000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff3382000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff35a1000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff37b8000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff39bd000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff3bce000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff3f82000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff4240000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff447c000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff4714000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff4a0c000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff4c5c000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff4fa6000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff51cf000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff5525000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff5747000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff598e000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff5b97000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff5dac000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff5fb6000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff62e6000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff64fb000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff6704000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff69fe000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff6c25000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff6e65000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff70d7000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff72f0000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff74fb000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff775b000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff7979000.
warning: Memory read failed for corefile section, 1048576 bytes at 0x7ffff7bcd000.
Saved corefile core.7393

I now have a core file which, so, if you want, I can do more debugging
(if you tell me the specific commands to invoke, starting with the "gdb
command line").

I cannot say what triggered the crash; I switched back to the emacs
window to find it nonresponsive and then I switched to the gdb screen
window to discover that emacs crashed.

-- 
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
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