[slime-devel] Re: Allegro 6.2 problem

[Peter Seibel]

Luke Gorrie <luke at bluetail.com> writes:

> Peter Seibel <peter at javamonkey.com> writes:
>
>> Luke Gorrie <luke at bluetail.com> writes:
>>
>>> Peter Seibel <peter at javamonkey.com> writes:
>>>
>>>> CL-USER> (compile-file "test-debug.lisp")
>>>> Error: Received signal number 11 (Segmentation violation)
>>>>   [condition type: SYNCHRONOUS-OPERATING-SYSTEM-SIGNAL]
>>>>
>>>> Restart actions (select using :continue):
>>>>  0: Prompt for a different filename to compile
>>>>  1: Abort handling SLIME request.
>>>>  2: Abort entirely from this process.
>>>> [Current process: repl-thread]
>>>> [1] CL-USER(1): 
>>>>
>>>> Typing Allegro commands (e.g. :cont 1) doesn't seem to do anything.
>>>> C-c C-c gets me into sldb where I can use one of the ABORT restarts to
>>>> get back to the main REPL. But this seems wrong.
>>>
>>> I find it troubling that so many simple errors like this cause SIGSEGV
>>> in ACL, but that's another story.
>>>
>>> Can you try again from CVS? From the ChangeLog I think that Brian
>>> Downing has probably fixed this.
>>
>> Nope. His fix fixed my other problem (with the interactive restart)
>> but not this one.
>
> Er, I hadn't realised that the segfaults were our fault :-)

Heh.

> The segfault is triggered in SLDB when we call `debug:output-frame' to
> format a particular stack frame for the backtrace. I don't know what's
> special about this frame, but poking around in the TTY debugger I
> noticed that `debug:frame-visible-p' returns NIL for it. So, as a
> pretty lame workaround, I changed the backtrace to filter out all
> frames that aren't visible-p.
>
> Don't know if this really solved the problem, so please give a shout
> if there are any more of these segfaults.

Well it seems to have worked--now I end up in SLDB with an error about
the file not existing which is what I'd expect. Cool.

-Peter

-- 
Peter Seibel                                      peter at javamonkey.com

         Lisp is the red pill. -- John Fraser, comp.lang.lisp