ip_tunnel: use WRITE_ONCE in ip_tunnel_encap_setup

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Update ip_tunnel_encap_setup() to use WRITE_ONCE() when writing
to encap fields (type, sport, dport, flags) and hlen fields.
This ensures that concurrent lockless readers (like fill_info)
do not see torn writes.

Also remove the unsafe memset() on t->encap which could cause
concurrent readers to transiently see zeroed fields.
Removing it also fixes a bug where t->encap was left cleared
even if ip_encap_hlen() failed, resulting in partial configuration.

Fixes: 5632848653 ("net: Changes to ip_tunnel to support foo-over-udp encapsulation")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Link: https://patch.msgid.link/20260907075846.2913645-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Eric Dumazet 2026-09-07 07:58:40 +00:00 • committed by Jakub Kicinski

parent 40a2b90f51

commit 88b84cae6b

1 changed files with 6 additions and 8 deletions

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net/ipv4/ip_tunnel.c

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