Re: infloop when removing character

[Miles Bader <miles@lsi.nec.co.jp>]

Simon Josefsson <jas@extundo.com> writes:
> > Hmmm, I've seen this `infinite loop in mallopt' hang too, but it was on
> > one my personal `very hacked' branches of emacs, so I assumed it was my
> > bug.  So you're seeing this in vanilla CVS emacs?
> 
> Yes, I don't have any changes, not even elisp changes.
> 
> > I guess this is malloc heap corruption (and so a bitch to find).
> 
> Perhaps it is a result from a error-within-a-error like Richard
> suggested.

My hangs look like what Gerd's seeing, but I don't notice any errors
involved.

For me they always seem to be in mallopt called from malloc called from
the regex code, called from within emacs' font-handling code; I've
appended an example backtrace.

> Since the process has crashed now I'll have to wait for it to happen
> again until I can test more ideas.

Heh, it seems to be happening more and more often for me, so I usually
don't have long to wait.  :-(

I'll grovel at this a bit more, but I'm not sure there's much I can
find out at this stage.  I'll try re-compiling using the debugging
options Gerd used...

-Miles


   Program received signal SIGTSTP, Stopped (user).
   0x405e310f in mallopt () from /lib/libc.so.6
   (gdb) ba
   #0  0x405e310f in mallopt () from /lib/libc.so.6
   #1  0x405e3d10 in mallopt () from /lib/libc.so.6
   #2  0x0815b19e in emacs_blocked_malloc (size=512)
       at /usr/local/src/emacs-tiling/src/alloc.c:966
   #3  0x405e1c68 in malloc () from /lib/libc.so.6
   #4  0x0815aacc in xmalloc (size=512)
       at /usr/local/src/emacs-tiling/src/alloc.c:523
   #5  0x08150d2f in regex_compile (pattern=0x853e948 "-cdac$", size=6,
       syntax=3408388, bufp=0x82eb20c)
       at /usr/local/src/emacs-tiling/src/regex.c:2466
   #6  0x08159db0 in re_compile_pattern (pattern=0x853e948 "-cdac$", length=6,
       bufp=0x21) at /usr/local/src/emacs-tiling/src/regex.c:5994
   #7  0x0814ab6d in compile_pattern_1 (cp=0x82eb204, pattern=945015340,
       translate=1211100160, regp=0x0, posix=0, multibyte=0)
       at /usr/local/src/emacs-tiling/src/search.c:163
   #8  0x0814acea in compile_pattern (pattern=945015340, regp=0x0,
       translate=1211100160, posix=0, multibyte=0)
       at /usr/local/src/emacs-tiling/src/search.c:234
   #9  0x0814b382 in fast_c_string_match_ignore_case (regexp=945015340,
       string=0xbfffde60 "-bitstream-bitstream vera sans mono-medium-r-normal--11-110-75-75-c-70-iso8859-1") at /usr/local/src/emacs-tiling/src/search.c:487
   #10 0x080dffcd in font_rescale_ratio (
       name=0xbfffde60 "-bitstream-bitstream vera sans mono-medium-r-normal--11-110-75-75-c-70-iso8859-1") at /usr/local/src/emacs-tiling/src/xfaces.c:2269
   #11 0x080e0278 in split_font_name (f=0x21, font=0xbfffdf00, numeric_p=1)
       at /usr/local/src/emacs-tiling/src/xfaces.c:2292
   #12 0x080e1208 in set_lface_from_font_name (f=0x9198630, lface=1224195320,
       fontname=948528004, force_p=0, may_fail_p=1)
       at /usr/local/src/emacs-tiling/src/xfaces.c:3250
   #13 0x080e7395 in realize_default_face (f=0x9198630)
       at /usr/local/src/emacs-tiling/src/xfaces.c:6633
   #14 0x080e6f22 in realize_basic_faces (f=0x9198630)
       at /usr/local/src/emacs-tiling/src/xfaces.c:6571
   #15 0x080ded38 in recompute_basic_faces (f=0x9198630)
       at /usr/local/src/emacs-tiling/src/xfaces.c:955
   #16 0x08092acd in init_iterator (it=0xbfffe130, w=0x925a940, charpos=-1,
       bytepos=-1, row=0x0, base_face_id=DEFAULT_FACE_ID)
       at /usr/local/src/emacs-tiling/src/xdisp.c:2009
   #17 0x0809a566 in x_consider_frame_title (frame=1226409520)
       at /usr/local/src/emacs-tiling/src/xdisp.c:7810
   #18 0x0809a899 in prepare_menu_bars ()
       at /usr/local/src/emacs-tiling/src/xdisp.c:7869
   #19 0x0809cdbe in redisplay_internal (preserve_echo_area=0)
       at /usr/local/src/emacs-tiling/src/xdisp.c:9668
   #20 0x0809c8cd in redisplay () at /usr/local/src/emacs-tiling/src/xdisp.c:9458
   #21 0x08117294 in read_char (commandflag=1, nmaps=4, maps=0xbfffea50,
       prev_event=405734956, used_mouse_menu=0xbfffea88)
       at /usr/local/src/emacs-tiling/src/keyboard.c:2871
   #22 0x0811df87 in read_key_sequence (keybuf=0xbfffebb0, bufsize=30,
       prompt=405734956, dont_downcase_last=0, can_return_switch_frame=1,
       fix_current_buffer=1) at /usr/local/src/emacs-tiling/src/keyboard.c:8825
   #23 0x081147d7 in command_loop_1 ()
       at /usr/local/src/emacs-tiling/src/keyboard.c:1504
   #24 0x0817066d in internal_condition_case (bfun=0x8114650 <command_loop_1>,
       handlers=405846076, hfun=0x8114210 <cmd_error>)
       at /usr/local/src/emacs-tiling/src/eval.c:1333
   #25 0x081144fb in command_loop_2 ()
       at /usr/local/src/emacs-tiling/src/keyboard.c:1292
   #26 0x081701ea in internal_catch (tag=33, func=0x81144e0 <command_loop_2>,
       arg=405734956) at /usr/local/src/emacs-tiling/src/eval.c:1094
   #27 0x081144b1 in command_loop ()
       at /usr/local/src/emacs-tiling/src/keyboard.c:1271
   #28 0x08113fc2 in recursive_edit_1 ()
       at /usr/local/src/emacs-tiling/src/keyboard.c:987
   #29 0x081140db in Frecursive_edit ()
       at /usr/local/src/emacs-tiling/src/keyboard.c:1043
   #30 0x08112972 in main (argc=3, argv=0xbffff194)
       at /usr/local/src/emacs-tiling/src/emacs.c:1666

-- 
"Whatever you do will be insignificant, but it is very important that
 you do it."  Mahatma Ghandi