On Wed, Jul 24, 2024 at 11:50:12PM +0200, Stefano Brivio wrote:
> 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>

Excellent, I can run these tests again.

Tested-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  test/memory/passt    | 13 ++++++++++---
>  test/passt.mem.mbuto |  9 +--------
>  2 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/test/memory/passt b/test/memory/passt
> index 1193af8..bf78c8f 100644
> --- a/test/memory/passt
> +++ b/test/memory/passt
> @@ -44,7 +44,7 @@ endef
>  def	start_stop_diff
>  guest	sed /proc/slabinfo -ne 's/^\([^ ]* *[^ ]* *[^ ]* *[^ ]*\).*/\\\1/p' > /tmp/slabinfo.before
>  guest	cat /proc/meminfo > /tmp/meminfo.before
> -guest	/bin/passt.avx2 -l /tmp/log -s /tmp/sock -P /tmp/pid __OPTS__ --netns-only
> +guest	/bin/passt.avx2 -l /tmp/log -s /tmp/sock -P /tmp/pid __OPTS__
>  sleep	2
>  guest	cat /proc/meminfo > /tmp/meminfo.after
>  guest	sed /proc/slabinfo -ne 's/^\([^ ]* *[^ ]* *[^ ]* *[^ ]*\).*/\\\1/p' > /tmp/slabinfo.after
> @@ -78,9 +78,16 @@ guest	mount -o bind /proc /test/proc
>  guest	mount -o bind /dev /test/dev
>  guest	cp -Lr /bin /lib /lib64 /usr /sbin /test/
>  
> +guest	exec switch_root /test /bin/sh
> +
>  guest	ulimit -Hn 300000
> -guest	unshare -rUm -R /test
> -guest	chroot .
> +guest	unshare -rUn
> +guest	ip link add eth0 type dummy
> +guest	ip link set eth0 up
> +guest	ip address add 192.0.2.2/24 dev eth0
> +guest	ip address add 2001:db8::2/64 dev eth0
> +guest	ip route add default via 192.0.2.1
> +guest	ip -6 route add default via 2001:db8::1 dev eth0
>  
>  guest	meminfo_size() { grep "^$2:" $1 | tr -s ' ' | cut -f2 -d ' '; }
>  guest	meminfo_diff() { echo $(( $(meminfo_size $2 $3) - $(meminfo_size $1 $3) )); }
> diff --git a/test/passt.mem.mbuto b/test/passt.mem.mbuto
> index 56f5139..532eae0 100755
> --- a/test/passt.mem.mbuto
> +++ b/test/passt.mem.mbuto
> @@ -12,7 +12,7 @@
>  
>  PROGS="${PROGS:-ash,dash,bash chmod ip mount insmod mkdir ln cat chmod modprobe
>         grep mknod sed chown sleep bc ls ps mount unshare chroot cp kill diff
> -       head tail sort tr tee cut nm which}"
> +       head tail sort tr tee cut nm which switch_root}"
>  
>  KMODS="${KMODS:- dummy}"
>  
> @@ -29,13 +29,6 @@ COPIES="${COPIES} ../passt.avx2,/bin/passt.avx2"
>  FIXUP="${FIXUP}"'
>  ln -s /bin /usr/bin
>  chmod 777 /tmp
> -ip link add eth0 type dummy
> -ip link set eth0 up
> -ip address add 192.0.2.2/24 dev eth0
> -ip address add 2001:db8::2/64 dev eth0
> -ip route add default via 192.0.2.1
> -ip -6 route add default via 2001:db8::1 dev eth0
> -sleep 2
>  sh +m
>  '
>  

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson