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Re: Weird modprobe problems


This was all my own fault. I had a file /etc/modprobe.d/local with a long list of disabled modules, that is lines like

install jbd /bin/true

I don't even quite remember why it was there, but it is probably related to mounting removable media which would try a long list of different file system types and cause a lot of warnings and slow things down. For some reason this stupid thing has never bitten me before.

Anyway, these lines were taken into account when building the initrd file, so several necessary modules were left out, resulting in an unusable initrd file.

I do feel a bit daft, but at least I'm now running linux 2.6.15 smp on my computer and it works great :-) Always look on the bright side ...


René Seindal wrote (09-02-2006 00:52):

I have a problem with modprobe on one computer. Due to some unidentified problem with modprobe I'm having a lot of problems upgrading a computer to linux 2.6.15 smp.

When installing the debian kernel and booting I got loads of messages complaining about "Unknown symbol journal_xxx". For some reason the initrd didn't load the jbd module needed by ext3.

After a lot of searching and rebooting (one feels almost like an MSCE by now :-) I found out that mkinitramfs uses modprobe to figure out what depends on want.

Mkinitramfs does a

    modprobe --set-version=2.6.15-1-686-smp --show-depends jbd

which on my system gives:

    install /bin/true

Comparing with other systems (with other versions) I get output like:

    insmod /lib/modules/2.6.15-1-686/kernel/fs/jbd/jbd.ko

For ext3 I get:

    insmod /lib/modules/2.6.15-1-686-smp/kernel/fs/mbcache.ko
    install /bin/true
    insmod /lib/modules/2.6.15-1-686-smp/kernel/fs/ext3/ext3.ko

which should be

    insmod /lib/modules/2.6.15-1-686-smp/kernel/fs/mbcache.ko
    insmod /lib/modules/2.6.15-1-686-smp/kernel/fs/jbd/jbd.ko
    insmod /lib/modules/2.6.15-1-686-smp/kernel/fs/ext3/ext3.ko

As a consequence I get an unusable initrd file because a lot of needed modules are missing. I have only identified jbd, but there are certainly other missing too. I have compared the contents of different initrd files and the ones on the problematic system are much too small.

I have tested this on three systems: a Soltek Qbic system with problems (2.6.15-1-686-smp and 2.6.15-1-686), an Asus M2N laptop (2.6.15-1-686) and a HP Proliant server (2.6.12-1-686-smp), both without problems.

Modprobe only misbehaves on the Soltec Qbic system.

Besides the different kernel versions they are very much alike. All run Etch (testing) and have

    # dpkg -l module-init-tools
ii module-init-to 3.2.2-1 tools for managing Linux kernel modules

I have uninstalled modutils from all systems.

Its late now and I want to sleep, but until now I have been unable to find out why modprobe on the Qbic doesn't work.

I have looked in the files in /lib/modules/2.6.15-1-686-smp/modules.* and they have the same lines for the modules I tested. The correct dependencies are there on all systems.

I was unable to install 2.6.15-1-686-smp or 2.6.15-1-686 on the Qbic because mkinitramfs was unable to create a bootable initrd file. In the end I installed the -smb kernel on my laptop and copied the initrd file over with scp, and the Qbic could boot. I cannot, however, upgrade the kernel now without resorting to similar tricks.

I haven't reported any bugs, because I haven't got a clue about whats wrong, except the symptoms described above. There is probably something misconfigured on the Qbic since the others don't have problems, but what?

A bit of help would be very much appreciated.

René Seindal (rene@seindal.dk)

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