test: Fix memory/passt tests, --netns-only is not a valid option for passt

This used to work on my setup as I kept reusing an old mbuto
(initramfs) image, but since commit 65923ba79877 ("conf: Accept
duplicate and conflicting options, the last one wins"), --netns-only
is, as originally intended, a pasta-only option.

I had used --netns-only, here, to prevent passt from trying to detach
its own user namespace, which is not permitted as we're in a chroot,
see unshare(2). In turn, we need the chroot because passt can't pivot
root directly into its own empty filesystem using an initramfs.

Use switch_root into the tmpfs mountpoint instead of chroot, so that
we can still detach user namespaces.

Note that in the mbuto images, we can't switch to nobody as we have
no password entries at all, so we need to detach a further user
namespace before starting passt, to trick passt into running as UID
0.

Given the new sequence, it's now more convenient to directly switch
to a detached network namespace as well, which means we need to move
the initialisation of the dummy network from the init script into the
test script.

Reported-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions