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tcp: annotate data-races on tp->segs_in and tp->data_segs_in

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tcp_segs_in() can be called from BH, while socket spinlock
is held but socket owned by user, eventually reading these
fields from tcp_get_info()

Found by code inspection, no need to backport this patch
to older kernels.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2021-11-15 11:02:42 -08:00 committed by David S. Miller
parent d2489c7b6d
commit 0307a0b74b
2 changed files with 10 additions and 4 deletions
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8
include/net/tcp.h
View File

@ -2172,9 +2172,13 @@ static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
u16 segs_in;
segs_in = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
tp->segs_in += segs_in;
/* We update these fields while other threads might
* read them from tcp_get_info()
*/
WRITE_ONCE(tp->segs_in, tp->segs_in + segs_in);
if (skb->len > tcp_hdrlen(skb))
tp->data_segs_in += segs_in;
WRITE_ONCE(tp->data_segs_in, tp->data_segs_in + segs_in);
}
/*

6
net/ipv4/tcp.c
View File

@ -3769,10 +3769,12 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
tcp_get_info_chrono_stats(tp, info);
info->tcpi_segs_out = tp->segs_out;
info->tcpi_segs_in = tp->segs_in;
/* segs_in and data_segs_in can be updated from tcp_segs_in() from BH */
info->tcpi_segs_in = READ_ONCE(tp->segs_in);
info->tcpi_data_segs_in = READ_ONCE(tp->data_segs_in);
info->tcpi_min_rtt = tcp_min_rtt(tp);
info->tcpi_data_segs_in = tp->data_segs_in;
info->tcpi_data_segs_out = tp->data_segs_out;
info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;