ramdisk: busybox's depmod is broken

[jan grant]

Noting this here so it doesn't get lost, although we'll look to address it asap.

Had problems trying to introduce an upstream mellanox driver into the ramdisk image. The problem turned out to be that the ramdisk image (nova baremetal's bootstrap initramfs) carries busybox's depmod, which it invokes after boot.

This doesn't respect the typical depmod search order (updates / built-in) and thus we wound up with a random shuffling of the new mlx4_en "relying" on the old mlx4_core, which didn't supply compatible symbols.

I think the right thing to do is to ensure that the ramdisk images come with a full depmod already run at image build time, and don't try to run it after boot.

(If there's a use case that requires a late depmod, then that use-case should probably also solve getting a working depmod binary onto the ramdisk.)

[Michele Baldessari (michele)]

With ironic's move to IPA I see that depmod is the same as the one used on a stock centos box (i.e. from kmod). I am settings this as fix released, please do let me know if you disagree so we can reopen it and discuss the next steps.

Thanks,
Michele