Re: [emacs-unicode-2] Segmentation fault 0x081b3df2 in xftfont_draw

[Leo]

Dear Kenichi,

----- Kenichi Handa (2007-04-13) wrote:-----

>> Here is a backtrace of an Emacs crash. One can encounter this often
>> by moving cursor over links etc. It only happens when using xft font.
>
>> Software: GNU Emacs 23.0.0.11 (i686-pc-linux-gnu, X toolkit) of
>> 2007-04-11
>
>> [2 xft_crash.log <text/plain (7bit)>]
>> Program received signal SIGSEGV, Segmentation fault.
> [...]
>> (gdb) bt full
>> #0  0x081b3df2 in xftfont_draw (s=0xbfb8f4f0, from=0, to=1, x=387, y=275, 
>>     with_background=0) at xftfont.c:501
>>         f = (FRAME_PTR) 0x8c75490
>>         face = (struct face *) 0xa9a08c8
>>         xftface_info = (struct xftface_info *) 0x0
>
> The crash is because xftface_info is NULL, but I can't
> reproduce it.  My Emacs configuration is almost the same as
> yours.
>
> GNU Emacs 23.0.0.30 (i686-pc-linux-gnu, X toolkit, Xaw3d
> scroll bars) of 2007-04-13 on etlken
>
> I run configure with "--enable-font-backend", and start
> emacs with "--enable-font-backend".  As you said you are
> using Xft font, I think you did the same.  Can't you show me
> the exact operation to produce that bug by starting Emacs
> with "-Q --enable-font-backend -fn SOMEFONT"?
>
> ---
> Kenichi Handa
> address@hidden

It happens usually when there are many links in a buffer such as in ERC
or W3M. I can move around mouse in a w3m buffer with tons of links (such
as www.6park.com) to catch a crash, which usually happens within a few
minutes. I just catch one with 'emacs -Q'. Unfortunately I don't know
the exact recipe to trigger a crash.

The following can help you see the bug although it won't crash Emacs:

         o  emacs -Q --enable-font-backend -fn SOMEFONT
         o  C-u 3 2 M-x hanoi

You should see the frame flickering like TV disturbed by static. Also
you can see CPU usage by Xorg and Emacs increased as follows:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND 
28208 root      15   0  283m  82m 8140 S 69.6  8.4  21:22.20 Xorg               
23199 leo       15   0 23284  15m 5964 R  6.5  1.6   0:00.64 emacs 

I tested this in latest source: GNU Emacs 23.0.0.12 (i686-pc-linux-gnu,
X toolkit) of 2007-04-13 on Fedora 6.

HTH
-- 
Leo <sdl.web AT gmail.com>                         (GPG Key: 9283AA3F)