Re: modules problems

[rulnick@seas.ucla.edu]

Several weeks ago I submitted a question about modules that led to
about a dozen replies.  More recently, Dale Scheetz brought up some
related problems, also much discussed.  I'd like to summarize briefly,
both for archival purposes and to point out what I see as unresolved
issues.

After a rebuild (makes: config, dep, clean, zlilo, modules,
modules_install) I got errors of the type

   *** Unresolved symbols in module...

from 'depmod -a', and 

   ...: wrong version
   Failed to load module! The symbols from kernel 1.2.13 don't match 1.2.13

from 'modprobe' during the boot sequence.  Steffen Mueller suggested
making mrproper (for those not using the debian development tree),
followed by config, dep, clean, modules, modules_install, zlilo; note
that zlilo is last in his list.  He also suggested answering 'y' to
CONFIG_MODVERSIONS during the config phase (corroborated by Gerry
Jensen), which I had done.  Dale Scheetz pointed out the value of
'lsmod' to view loaded modules, and Bill Hogan mentioned 'depmod -e
XXX.o' and 'cat /proc/ksyms' as tools for rooting out unresolved
symbols for module XXX (thanks Bill!).  Finally, I discovered that
skipping the 'make modules' and 'make modules_install' steps appears
to eliminate the "...: wrong version" and "Failed to load..." errors
(!).

Then, as mentioned above, Dale Scheetz had problems loading modules
after makes of config, dep, clean, zImage, modules, modules_install.
He followed up by saying (with help from Bruce (Perens, I presume))
that one needs

	CONFIG_MODULES: y
	CONFIG_KERNELD: y

and to say 'm' (undocumented?) in answer to compilation options for
things to be loaded as modules.  (Personally I am not clear on this,
and would really appreciate a more detailed explanation.)

Please accept my apologies, and correct me, if anything I've said is
incorrect.  Now for unresolved issues:

Unresolved Issues (IMHO)
------------------------
1. What exactly happens with 'make modules' and 'make
modules_install'?  Can someone describe the algorithm, or at least the
philosophy?

2. Should 'make modules' and 'make modules_install' *precede* or
*follow* the kernel-building 'make zlilo' (or 'zImage' or 'zdisk')?

3. Are there instances when 'make modules' and 'make modules_install'
should *not* be used?

4. What are the appropriate settings, *and why*, for 

	CONFIG_MODVERSIONS?
	CONFIG_MODULES?
	CONFIG_KERNELD?

I certainly understand if people are tired of talking about modules,
so my apologies to the exasperated.  I will be happy to continue
discussion by private email, but for now it seems to me that the list
is still the best place for this discussion.

Regards,

John