2.2.20 - Possible module symbol bug

2.2.20 - Possible module symbol bug

[David Ranch]

Hello esteemed Linux gurus,


I think I've found a bug in 2.2.20.  Specifically, 
if I compile up a 2.2.20 kernel on a Mandrake 7.0 box
(glibc 2.1.3 - modutil 2.1.121) and run "depmod -a", all 
IPMASQ modules, loop, and ide-scsi modules fail dependencies.

--
#depmod -a
/lib/modules/2.2.20/scsi/ide-scsi.o: unresolved symbol(s)
/lib/modules/2.2.20/block/loop.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_vdolive.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_quake.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_raudio.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_irc.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol(s)
/lib/modules/2.2.20/ipv4/ip_masq_user.o: unresolved symbol(s) 

#modprobe --debug ip_masq_ftp
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_new
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_put
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_listen
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_control_add
/lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_out_get 
--

If I do this make config on a a Mandrake 7.2 machine 
(Glibc 2.1.3 - modutils 2.3.21), only the loop module fails.

If I do this on a Mandrake 8.0 machine (Glibc 2.2.2 - modutils 2.4.3), 
everything is FINE.


So, playing around with the kernel config a little, I've found
that if I -do not- enable "CONFIG_MODVERSIONS", then everything
is ok on all machines.

Any thoughts on what is going on?  If possible, please CC: on the
the reply as I'm not on the linux-kernel list nor can my email
box handle the additional load.  ;-)  Thanks.

Ps.  If anyone would like a copy of the .config or the System.map
     files, please email me.

--David

Re: 2.2.20 - Possible module symbol bug

[Keith Owens]

On Fri, 09 Nov 2001 12:48:34 -0800, 
David Ranch <dranch@juniper.net> wrote:
>I think I've found a bug in 2.2.20.  Specifically, 
>if I compile up a 2.2.20 kernel on a Mandrake 7.0 box
>(glibc 2.1.3 - modutil 2.1.121) and run "depmod -a", all 
>IPMASQ modules, loop, and ide-scsi modules fail dependencies.

Broken kernel Makefiles, http://www.tux.org/lkml/#s8-8

Re: 2.2.20 - Possible module symbol bug

[David Ranch]

Hello Keith,

It's been a LONG time since I've heard from you.  I hope
all is well.

--
mv .config ..
make mrproper
mv ../.config .
make oldconfig
make dep clean bzImage modules
install, boot
--

I did start off with a clean config though I didn't do
a "mrproper".  I re-tested on the MD7.0 box and
"mrproper" solved my issue.  I haven't had to do this
step since the old 2.0.2x days and I feel somewhat
embarrassed by this.

Thanks again for setting me strait though. I am
curious for an explanation from the powers at be to
why this hit me now though I've been compiling kernels
without "mrproper" for years.  Am I just lucky?  ;-)

--David



At 05:28 PM 11/10/01 +1100, Keith Owens wrote:
 >On Fri, 09 Nov 2001 12:48:34 -0800,
 >David Ranch <dranch@juniper.net> wrote:
 >>I think I've found a bug in 2.2.20.  Specifically,
 >>if I compile up a 2.2.20 kernel on a Mandrake 7.0 box
 >>(glibc 2.1.3 - modutil 2.1.121) and run "depmod -a", all
 >>IPMASQ modules, loop, and ide-scsi modules fail dependencies.
 >
 >Broken kernel Makefiles, http://www.tux.org/lkml/#s8-8
.----------------------------------------------------------------------------.
|  David A. Ranch - Linux/Networking/PC hardware         dranch@trinnet.net  |
!----                                                                    ----!
`----- For more detailed info, see http://www.ecst.csuchico.edu/~dranch -----'

Re: 2.2.20 - Possible module symbol bug

[Keith Owens]

On Sat, 10 Nov 2001 20:38:58 -0800, 
David Ranch <dranch@trinnet.net> wrote:
>I did start off with a clean config though I didn't do
>a "mrproper".  I re-tested on the MD7.0 box and
>"mrproper" solved my issue.  I haven't had to do this
>step since the old 2.0.2x days and I feel somewhat
>embarrassed by this.
>
>Thanks again for setting me strait though. I am
>curious for an explanation from the powers at be to
>why this hit me now though I've been compiling kernels
>without "mrproper" for years.  Am I just lucky?  ;-)

The implementation of module symbol versions is fundamentally broken.
The idea is good, to prevent incompatible modules being loaded into
your kernel and crashing it, but the implementation is built on several
assumptions that are not valid.  Total redesign coming up in kernel
2.5.  See the build 2.5 history package[1], expecially the html files.

Sometimes modversions work, more often then don't.

[1] http://sourceforge.net/project/showfiles.php?group_id=18813, under
    History.

Re: 2.2.20 - Possible module symbol bug

[Eric Preston]

> #depmod -a
> /lib/modules/2.2.20/scsi/ide-scsi.o: unresolved symbol(s)
> /lib/modules/2.2.20/block/loop.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_vdolive.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_quake.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_raudio.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_irc.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol(s)
> /lib/modules/2.2.20/ipv4/ip_masq_user.o: unresolved symbol(s) 
> 
> #modprobe --debug ip_masq_ftp
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_new
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_put
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_listen
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_control_add
> /lib/modules/2.2.20/ipv4/ip_masq_ftp.o: unresolved symbol ip_masq_out_get 

I noticed the same problem when recently building 2.2.20,

Enable "prompt for experimental code"
And choose the appropriate masq options that now appear,
and the masq stuff goes away. Something to do with CONFIG_MASQUERADE_MOD
not being set, was in a hurry so i didn't bother to look into it more,

regards,
Eric