neighbour: Convert neigh_table.entries to refcount_t.

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We will allocate neigh_table for each netns and free it
when netns is destroyed.

neigh_ifdown() cleans up all neighbour entries during netns
dismantle, but there is no synchronisation between timers because
neigh_del_timer() uses timer_delete() to stop a timer.

If neigh_table were freed while timer were running, neigh_destroy()
would touch the freed table.

If we called timer_delete_sync() in neigh_flush_one() under
tbl->lock, lockdep would complain although it is false-positive.

Let's convert neigh_table.entries to refcount_t and destruct
neigh_table only when the count reaches 0.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-12-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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This commit is contained in:

Kuniyuki Iwashima 2026-09-02 20:36:52 +00:00 • committed by Jakub Kicinski

parent e265c2c432

commit 1c2b205094

2 changed files with 41 additions and 19 deletions

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2

include/net/neighbour.h

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64

net/core/neighbour.c

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