diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-04-05 16:35:38 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-04-06 12:05:41 -0700 |
| commit | 40570375356c874b1578e05c1dcc3ff7c1322dbe (patch) | |
| tree | 54c7a52bfdd4e302f877e93dc94adb09cfa3aac4 /net/ipv4/tcp_cubic.c | |
| parent | 487dc3ca60e3e420d54bcc613cb49e8e85f34569 (diff) | |
| download | linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.bz2 | |
tcp: add accessors to read/set tp->snd_cwnd
We had various bugs over the years with code
breaking the assumption that tp->snd_cwnd is greater
than zero.
Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added
in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction")
can trigger, and without a repro we would have to spend
considerable time finding the bug.
Instead of complaining too late, we want to catch where
and when tp->snd_cwnd is set to an illegal value.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_cubic.c')
| -rw-r--r-- | net/ipv4/tcp_cubic.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 24d562dd6225..b0918839bee7 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -334,7 +334,7 @@ static void cubictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (!acked) return; } - bictcp_update(ca, tp->snd_cwnd, acked); + bictcp_update(ca, tcp_snd_cwnd(tp), acked); tcp_cong_avoid_ai(tp, ca->cnt, acked); } @@ -346,13 +346,13 @@ static u32 cubictcp_recalc_ssthresh(struct sock *sk) ca->epoch_start = 0; /* end of epoch */ /* Wmax and fast convergence */ - if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence) - ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta)) + if (tcp_snd_cwnd(tp) < ca->last_max_cwnd && fast_convergence) + ca->last_max_cwnd = (tcp_snd_cwnd(tp) * (BICTCP_BETA_SCALE + beta)) / (2 * BICTCP_BETA_SCALE); else - ca->last_max_cwnd = tp->snd_cwnd; + ca->last_max_cwnd = tcp_snd_cwnd(tp); - return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U); + return max((tcp_snd_cwnd(tp) * beta) / BICTCP_BETA_SCALE, 2U); } static void cubictcp_state(struct sock *sk, u8 new_state) @@ -413,13 +413,13 @@ static void hystart_update(struct sock *sk, u32 delay) ca->found = 1; pr_debug("hystart_ack_train (%u > %u) delay_min %u (+ ack_delay %u) cwnd %u\n", now - ca->round_start, threshold, - ca->delay_min, hystart_ack_delay(sk), tp->snd_cwnd); + ca->delay_min, hystart_ack_delay(sk), tcp_snd_cwnd(tp)); NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTTRAINDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTTRAINCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); } } } @@ -438,8 +438,8 @@ static void hystart_update(struct sock *sk, u32 delay) LINUX_MIB_TCPHYSTARTDELAYDETECT); NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPHYSTARTDELAYCWND, - tp->snd_cwnd); - tp->snd_ssthresh = tp->snd_cwnd; + tcp_snd_cwnd(tp)); + tp->snd_ssthresh = tcp_snd_cwnd(tp); } } } @@ -469,7 +469,7 @@ static void cubictcp_acked(struct sock *sk, const struct ack_sample *sample) /* hystart triggers when cwnd is larger than some threshold */ if (!ca->found && tcp_in_slow_start(tp) && hystart && - tp->snd_cwnd >= hystart_low_window) + tcp_snd_cwnd(tp) >= hystart_low_window) hystart_update(sk, delay); } |