[PATCH net-next 0/5] net: make xdp config checks effective vs netif_xdp_propagate()

[Jakub Kicinski <kuba@kernel.org>]

Bonding (and netvsc) try to auto-propagate XDP programs down
to their lower devices. These programs were installed directly
with .ndo_bpf and not recorded in struct net_device of the lowers.
This makes all the config checks for features incompatible with XDP
ineffective - HDS, memory providers etc. use dev_xdp_prog_count()
and do not call down to the driver to ask it whether it has XDP
installed.

Record the state appropriately. dev_xdp_prog_count() will now
"see" the propagated programs.

The issue was discovered when reworking HW-GRO and XDP interactions.
I was trying to make sure HW-GRO is reliably disabled with XDP,
and discovered we have a way to bypass all checks with bonding.
Not treating this as a fix since it's admin-only self-inflicted
damage that nobody is reporting being bothered by in real life.

Jakub Kicinski (5):
  net: don't safety-check device features for XDP uninstall
  net: move dev_xdp_set_link() and dev_xdp_set_prog() up
  net: record XDP programs propagated to lower devices
  selftests/bpf: check XDP attach on a nested bond slave
  selftests/bpf: check replacing and detaching XDP on a bond through a
    link

 .../networking/net_cachelines/net_device.rst  |   1 +
 include/linux/netdevice.h                     |   7 +
 drivers/net/bonding/bond_main.c               |   4 +-
 drivers/net/hyperv/netvsc_bpf.c               |   2 +-
 drivers/net/hyperv/netvsc_drv.c               |   5 +-
 net/core/dev.c                                | 133 ++++++++++++------
 .../selftests/bpf/prog_tests/xdp_bonding.c    | 120 +++++++++++++++-
 7 files changed, 224 insertions(+), 48 deletions(-)

-- 
2.56.0