tcp_metrics: fix data-race in tcpm_suck_dst() vs fastopen

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[ Upstream commit ddf251fa2b ]

Whenever tcpm_new() reclaims an old entry, tcpm_suck_dst()
would overwrite data that could be read from tcp_fastopen_cache_get()
or tcp_metrics_fill_info().

We need to acquire fastopen_seqlock to maintain consistency.

For newly allocated objects, tcpm_new() can switch to kzalloc()
to avoid an extra fastopen_seqlock acquisition.

Fixes: 1fe4c481ba ("net-tcp: Fast Open client - cookie cache")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230802131500.1478140-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Eric Dumazet 2023-08-02 13:15:00 +00:00 • committed by Greg Kroah-Hartman

parent fd147efc96

commit d6d195f2e7

1 changed files with 5 additions and 4 deletions

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net/ipv4/tcp_metrics.c

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