How to ask for help on this list (was Re: Reproducible hard freeze
on 5.1-CURRENT)
Mike Makonnen
mtm at identd.net
Fri Jun 6 07:00:28 PDT 2003
On Fri, 6 Jun 2003 08:48:17 -0400
"Robin P. Blanchard" <Robin.Blanchard at gactr.uga.edu> wrote:
> Upon launching samba-2.2.8a (via ports) on the below system, the machine
> immediately hard freezes. I've included interesting portions of kernel
> config. Any suggestions how I can acquire more useful information ?
[snip]
> #options WITNESS
> #options WITNESS_DDB
> #options WITNESS_SKIPSPIN
> #options INVARIANTS
> #options INVARIANT_SUPPORT
> #options DIAGNOSTIC
[snip]
>
> #options SCHED_4BSD
> options SCHED_ULE
This is not to pick on you in particular. There have been a lot of these
lately and I just picked this one to reply to.
None of this is new, these points have already been made elsewhere and
people on this list should be familiar with them. But I'll go ahead and
point them out anyway.
If you experience a freeze, panic, or any other fatal problem please keep in
mind the following things:
1. There is a reason SCHED_ULE is labeled 'experimental'. It means that this is
a new feature that needs some more testing and deguggin. Don't be
surprised if it panics your system, eats your homework, or causes your hair
to fall out.
If you insist on using it, then please properly label your email with such
information, and at the very least try to determine if _not_ using it makes
your problems go away.
2. Before you report a problem enable all the debugging options in your kernel
configuration file. If you don't want to put up with the reduction in
performance, then build two kernels from the same source: one without the
debuging options and one with. When you hit a problem, boot into the
kernel with the debugging options and try to reproduce the problem. Report
any Lock Oreder Reversals (LORs) and other errors reported by the kernel.
When you do report a problem like "my box freezes" it is essential that you
at least have 'options DDB' in your kernel so you can attempt to enter the
kernel debugger and get an idea of what's happening. If enabling the
debugging options makes your problems go away, that is helpful information
in and of itself, so report it.
3. There is an entry in The Handbook and the Articles that provide information
on how to obtain debuging information from your kernel. Greg Lehey also has
an article about that in the works (see archives). Please read these before
you ask "How can I get more debugging information."
4. Some problems, are caused by faulty hardware. The ports tree has some
applications you can use to check your hardware (memtest86, etc). If you
see random panics and/or freezes it may be a good idea to use some
of these programs to check your hardware. Believe it or not, hardware does
fail, so don't discount this possibility.
5. You can greatly increase the chance that your problem gets resolved if you
provide good quality debugging information, and actually do some of the
diagnosing yourself. Even a partial attempt at solving the problem is
better than nothing.
6. Finally, please try to understand that this is a volunteer project. Few
developers actually get paid to work on FreeBSD, and when they do
it's usually for something specific that their employer needs. Most
developers give up free time during the week to work on FreeBSD.
So, it may not be possible to devote the time and energy you believe
your problem deserves.
Cheers.
--
Mike Makonnen | GPG-KEY: http://www.identd.net/~mtm/mtm.asc
mtm at identd.net | D228 1A6F C64E 120A A1C9 A3AA DAE1 E2AF DBCC 68B9
mtm at FreeBSD.Org| FreeBSD - The Power To Serve
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