Random bus error

Random bus error

[blacknwhite77]

Every couple of days, unexpectedly and without any specific trigger emacs crashes with bus error message in terminal. I have an elaborate "non optimized" .emacs file.
How should I go about debugging the issue?

I am using GNU Emacs 24.3.1, on Solaris operating system. GNU Emacs 24.3.1 (sparc-sun-solaris2.10, GTK+ Version 2.10.13)

RE: Random bus error

[Doug Lewan]

A few things come to mind right away.

1. Run emacs -Q to get a pure, minimal emacs. 
   If that crashes, then it is indeed an issue restricted to emacs. (And see point 2.)
You probably still want your customizations, so
2. Run emacs under a debugger. 
   When there's a crash grab whatever stack information you can. 
   In gdb(1GNU) the magic incantation is `thread apply all bt'.
   Your debugger may be different.
3. (setq debug-on-error t) will show you certain extreme errors in your non-optimized .emacs.
   They may not be the immediate source of the crash, 
   but fixing them will eliminate distracting failures.

Hope this helps.

-- 
,Doug
Douglas Lewan
Shubert Ticketing
(201) 489-8600 ext 224 or ext 4335

"This is a slow pup," he said continuing his ascent.


> -----Original Message-----
> On
> Behalf Of blacknwhite77
> Subject: Random bus error
> 
> Every couple of days, unexpectedly and without any specific trigger
> emacs crashes with bus error message in terminal. I have an elaborate
> "non optimized" .emacs file.
> How should I go about debugging the issue?
> 
> I am using GNU Emacs 24.3.1, on Solaris operating system. GNU Emacs
> 24.3.1 (sparc-sun-solaris2.10, GTK+ Version 2.10.13)

Re: Random bus error

[blacknwhite77]

Thank you for your response.
1. I have other emacs sessions open for a while with no issue. It seems a recent change in .emacs triggered the problem.
2. I have very little knowledge of emacs debugger. Is there documentation somewhere on how to run emacs under a debugger?
Also, as I mentioned earlier, this crash is very random and nothing in specific triggers it, so I am not sure how running under a debugger might help.
3. This seems to be the closest to what might help.
I did set the debug-on-error value in my .emacs, but my question is once the app crashes where do I find the crash log?

Thanks again.

Re: Random bus error

[Alexis]

blacknwhite77@gmail.com writes:

> 2. I have very little knowledge of emacs debugger. Is there
> documentation somewhere on how to run emacs under a debugger?

See the file etc/DEBUG.

> Also, as I mentioned earlier, this crash is very random and nothing in
> specific triggers it, so I am not sure how running under a debugger
> might help.

Running Emacs under e.g. gdb can allow one to query for information
about the call stack, values of various variables etc. immediately after
the crash has happened, and before such information is irretrievably
lost.

> 3. This seems to be the closest to what might help. I did set the
> debug-on-error value in my .emacs, but my question is once the app
> crashes where do I find the crash log?

`debug-on-error` is more for debugging Emacs Lisp, presenting
debugging-related information in a new buffer whilst Emacs is still
running. App crashes are probably more likely to be occurring at the C
level, hence the need to run Emacs under a C debugger such as gdb - as
distinct from using the ELisp debugging facilities built-in to Emacs
(e.g. EDebug), which one uses from within Emacs itself.


Alexis.