Re: [tlug] Newly compiled Kernel woes:defconfig

[Frank Bennett <bennett@example.com>]

On Tue, Jan 22, 2002 at 10:49:24AM +0800, Mancy, Raymond wrote:
> OK, went home last night and made boot disks, so I could go into rescue
> mode. ...the only problem is that it asks me for the image of the RH
> image...and it cant detect my PCMCIA cd-rom.....and it wont boot from my RH
> CD's on that machine...it boots from them fine on my desktop, and on the
> laptop my NT disks boot...
> 
> I think that I will just try and look on the net and try and find out how to
> fix this "unresolved Symbols" problem that I am getting whenever I try to
> insmod a module. I think that should fix things up hopefully

Ray,

You've received loadsa suggestions.  If this one feels like adding to the
confusion, pass it up.  But every other cook has had a shot at the stew, so
...

The "unresolved symbols" error is issued by insmod when hooks needed by the
module it is trying to load cannot be found in the kernel. The hooks may be
missing because:

  (a) the kernel doesn't match the module (i.e. the kernel is missing stuff
      that has to be compiled in in order for the module to do its thing); or
      
  (b) some other module, which contains the hooks, has not yet been
      loaded into the kernel.

If you load using "modprobe", you should seldom see this message, but only IF:

  o The kernel and the modules are a matched set (i.e. they were all created
    off the same configuration of the same source); AND

  o You have run "depmod -a" after installing the kernel and modules, and
    before using modprobe.

  o There is a copy of "System.map-<ver>" in your /boot directory that is
    identical to the file System.map created during the kernel/modules compile
    run (this file ends up in the top of the kernel source tree), and this
    file was in place when you ran "depmod -a".[1] This command analyzes the
    capabilities of the kernel and of the modules, and creates files that tell
    modprobe what modules depend on other modules, so it can save you lots of
    finger-work by just doing the right thing (most of the time).

If you are getting this error for ALL modules (even stuff like, say "insmod
fat"), then you should check your configuration to see if you have compiled
the kernel without loadable module support in the kernel.  You can check
quickly by going to the top of your kernel source tree and using "grep
CONFIG_MODULES .config".  If the answer is no, that's a problem you want to
fix.


[1] If you prefer, you can force depmod to use a map in a different place (see
"man depmod"), but it is a good idea to get the default working correctly,
since the scripts run at system startup typically issue "depmod -a", which
would overwrite your forced dependencies.


Hope this helps,
Frank Bennett
Nagoya