[PATCH net 0/3] vxlan: Fix NPDs when using nexthop objects

[Ido Schimmel <idosch@nvidia.com>]

With FDB nexthop groups, VXLAN FDB entries do not necessarily point to a
remote destination but rather to an FDB nexthop group. This means that
first_remote_{rcu,rtnl}() can return NULL and a few places in the driver
were not ready for that, resulting in NULL pointer dereferences.
Patches #1-#2 fix these NPDs.

Note that vxlan_fdb_find_uc() still dereferences the remote returned by
first_remote_rcu() without checking that it is not NULL, but this
function is only invoked by a single driver which vetoes the creation of
FDB nexthop groups. I will patch this in net-next to make the code less
fragile.

Patch #3 adds a selftests which exercises these code paths and tests
basic Tx functionality with FDB nexthop groups. I verified that the test
crashes the kernel without the first two patches.

Ido Schimmel (3):
  vxlan: Fix NPD when refreshing an FDB entry with a nexthop object
  vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects
  selftests: net: Add a selftest for VXLAN with FDB nexthop groups

 drivers/net/vxlan/vxlan_core.c               |  18 +-
 drivers/net/vxlan/vxlan_private.h            |   4 +-
 tools/testing/selftests/net/Makefile         |   1 +
 tools/testing/selftests/net/test_vxlan_nh.sh | 223 +++++++++++++++++++
 4 files changed, 237 insertions(+), 9 deletions(-)
 create mode 100755 tools/testing/selftests/net/test_vxlan_nh.sh

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2.51.0