printf doesn't work from kernel modules

[Garrett Cooper]

On Mon, Nov 22, 2010 at 5:38 AM, Dmitry Krivenok
<krivenok.dmitry at gmail.com> wrote:
> Hello Hackers,
> Recently I installed 8.1 on my laptop and recompiled the kernel.
> The system works fine, but I have a strange problem with my own
> trivial kernel module.
> I noticed that printf function doesn't produce any output (according to
> dmesg) if I call it from a module. Note, that the same module works
> perfectly on another 8.1 and CURRENT systems. Moreover, I added
> debug message (printf ("Bla bla bla\n");)  in my kernel and found that
> it works fine (i.e. works if compiled directly in kernel, but doesn't work
> from module). Same effect with stock 8.1 kernel.
>
> I see the same problem with examples in /usr/share/examples/kld.
>
> I don't believe this is a real problem in FreeBSD. I'm sure this is some
> kind of configuration issue, but I cannot understand what exactly is wrong.
>
> What could cause such behaviour?
> Any ideas?

Which example did you try and run (it looks like the dyn_sysctl test
would be a good one to try)?
-Garrett