Re: How to debug a locked backend ?

On Fri, Nov 18, 2005 at 03:55:01PM +0100, Csaba Nagy wrote:
> Richar, Martijn,
> 
> Thanks for answering, but I had to kill the process in the meantime. I
> tried kill -11 in the hope it will produce a core dump at least, but it
> either didn't dump core or I don't know where to look for it as I can't
> find it.



> So, in order to find out what's going on, what should I do if it happens
> again ? Use gdb, and do what ?
> Strace is a good idea, I'll do that too if there is a next time.

The most useful thing is to type "bt" to get a backtrace. Unfortunatly,
if you've got a stripped binary the output will be totally unreadable.
But we can hope.

strace tells you the system calls it's doing. If it's stuck in a loop
in userspace this won't print much useful, but that fact is useful in
itself. Finally there is ltrace which lists library calls. Somewhat
more invasive, but can sometimes produce something where strace
doesn't.

There are tables for the current locks, but you'll need to look in the
docs for that.

Have a nice day,
-- 
Martijn van Oosterhout      http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.