[PATCH net-next v2 0/3] align IPv4 teardown with IPv6 and fix driver regressions

[Yuyang Huang <yuyanghuang@google.com>]

This series aligns the IPv4 address teardown sequence with IPv6 by clearing
dev->ip_ptr early in inetdev_destroy() before freeing the multicast list and
individual IP addresses. This prevents RCU readers from accessing a partially
destroyed in_device structure.

However, clearing dev->ip_ptr early causes __in_dev_get_rtnl() to return NULL
during the notifier loop in inetdev_destroy(). This causes regressions in
some drivers (prestera and mac80211) that use this lookup helper in their
inetaddr notifier callbacks.

To prevent regressions and maintain bisectability, this series first fixes the
affected drivers (Patch 1 and 2) before applying the core IPv4 change (Patch 3).

An audit was performed on all other registered inetaddr and inet6addr notifier
listeners, and no other drivers were found to be affected.

Change in v2:
  - Split the original single patch into a 3-patch series.
  - Patch 1: Teach prestera to ignore duplicate RIF destruction events when the
    RIF is already gone, rather than returning -EEXIST and aborting the chain.
  - Patch 2: Fix mac80211 to use the valid ifa->ifa_dev from the event argument
    instead of looking it up via the netdevice.
  - Patch 3: The original change to clear dev->ip_ptr early.

Yuyang Huang (3):
  net: prestera: ignore duplicate RIF destruction events
  wifi: mac80211: use ifa_dev from event argument
  net: ipv4: clear dev->ip_ptr before destroying inetdev

 drivers/net/ethernet/marvell/prestera/prestera_router.c | 6 ++----
 net/ipv4/devinet.c                                      | 4 ++--
 net/mac80211/main.c                                     | 4 +---
 3 files changed, 5 insertions(+), 9 deletions(-)

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2.55.0.795.g602f6c329a-goog