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_metrics.c | |
| parent | 487dc3ca60e3e420d54bcc613cb49e8e85f34569 (diff) | |
| download | linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.gz | |
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_metrics.c')
| -rw-r--r-- | net/ipv4/tcp_metrics.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 0588b004ddac..7029b0e98edb 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -388,15 +388,15 @@ void tcp_update_metrics(struct sock *sk) if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) { val = tcp_metric_get(tm, TCP_METRIC_SSTHRESH); - if (val && (tp->snd_cwnd >> 1) > val) + if (val && (tcp_snd_cwnd(tp) >> 1) > val) tcp_metric_set(tm, TCP_METRIC_SSTHRESH, - tp->snd_cwnd >> 1); + tcp_snd_cwnd(tp) >> 1); } if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { val = tcp_metric_get(tm, TCP_METRIC_CWND); - if (tp->snd_cwnd > val) + if (tcp_snd_cwnd(tp) > val) tcp_metric_set(tm, TCP_METRIC_CWND, - tp->snd_cwnd); + tcp_snd_cwnd(tp)); } } else if (!tcp_in_slow_start(tp) && icsk->icsk_ca_state == TCP_CA_Open) { @@ -404,10 +404,10 @@ void tcp_update_metrics(struct sock *sk) if (!net->ipv4.sysctl_tcp_no_ssthresh_metrics_save && !tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) tcp_metric_set(tm, TCP_METRIC_SSTHRESH, - max(tp->snd_cwnd >> 1, tp->snd_ssthresh)); + max(tcp_snd_cwnd(tp) >> 1, tp->snd_ssthresh)); if (!tcp_metric_locked(tm, TCP_METRIC_CWND)) { val = tcp_metric_get(tm, TCP_METRIC_CWND); - tcp_metric_set(tm, TCP_METRIC_CWND, (val + tp->snd_cwnd) >> 1); + tcp_metric_set(tm, TCP_METRIC_CWND, (val + tcp_snd_cwnd(tp)) >> 1); } } else { /* Else slow start did not finish, cwnd is non-sense, |