diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-11-15 22:02:42 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-11-16 16:10:34 +0300 |
| commit | 0307a0b74b3af6ecb1c8b7f727376130b15bbf44 (patch) | |
| tree | 31f6f571d6c135b02a5dc6cf9f63dc5b860a36e0 | |
| parent | d2489c7b6d7d5ed4b32b56703c57c47bfbfe7fa5 (diff) | |
| download | linux-0307a0b74b3af6ecb1c8b7f727376130b15bbf44.tar.xz | |
tcp: annotate data-races on tp->segs_in and tp->data_segs_in
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>
| -rw-r--r-- | include/net/tcp.h | 8 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 6 |
2 files changed, 10 insertions, 4 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index 4da22b41bde6..05c81677aaf7 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -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); } /* diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 24d77a32c9cb..267b2b18f048 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -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; |