[PATCH net 0/2] ipv6: Fix suspicious RCU usage in route hardware flags notification

[Ido Schimmel <idosch@nvidia.com>]

fib6_info_hw_flags_set() is called by drivers to update the hardware
flags of an IPv6 route and to emit a notification when
fib_notify_on_flag_change is set. Drivers call it from process context
without RTNL or RCU, so when the route uses a nexthop object, building
the notification triggers suspicious RCU usage splats.

Patch #1 fixes the problem by holding RCU while building the
notification.

Patch #2 adds IPv4 and IPv6 test cases for routes that use nexthop
objects. Without patch #1, the IPv6 one triggers the splats.

Ido Schimmel (2):
  ipv6: Hold RCU when emitting route hardware flags notification
  selftests: netdevsim: Add FIB notification tests for nexthop objects

 net/ipv6/route.c                              |  7 +-
 .../net/netdevsim/fib_notifications.sh        | 66 +++++++++++++++++++
 2 files changed, 72 insertions(+), 1 deletion(-)

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2.56.0