Re: Race condition in module load causing undefined symbols

From: Stephen Lord
Date: Fri Jun 10 2005 - 22:32:18 EST


Andrew Morton wrote:
Stephen Lord <lord@xxxxxxx> wrote:

I am having troubles getting any recent kernel to boot successfully
on one of my machines, a generic 2.6GHz P4 box with HT enabled
running an updated Fedora Core 3 distro. This is present in
2.6.12-rc6. It does not manifest itself with the Fedora Core
kernels which have identical initrd contents as far as the
init script and the set of modules included goes.

The problem manifests itself as various undefined symbols from
module loads.


Peculiar. Module loading is all synchronous, isn't it?


Well, things are getting more bizarre, adding sleeps between
module loads cures the problem with missing symbols. I then
run into a problem with device mapper/lvm which seems to be
having problems setting up devices. In this section of
the init script:

umount /sys
echo Mounting root filesystem
mount -o defaults --ro -t ext3 /dev/root /sysroot
mount -t tmpfs --bind /dev /sysroot/dev
echo Switching to new root
switchroot /sysroot
umount /initrd/dev

The correct number of volumes are found, but adding a showlabels
command to the init script fails to display them, it spits out
errors about readdir failures in /dev/Volume00

The umount of /sys fails, the root mount fails and obviously, the
switchroot then fails.

I tried using the same config options as the redhat supplied
kernel without any success, this still has module symbol
problems.

I am baffled, but it looks like it is not a symbol table problem.

Steve

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