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| 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_lp.c | |
| parent | 487dc3ca60e3e420d54bcc613cb49e8e85f34569 (diff) | |
| download | linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.gz linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.bz2 linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.zip | |
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_lp.c')
| -rw-r--r-- | net/ipv4/tcp_lp.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c index 82b36ec3f2f8..ae36780977d2 100644 --- a/net/ipv4/tcp_lp.c +++ b/net/ipv4/tcp_lp.c @@ -297,7 +297,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample) lp->flag &= ~LP_WITHIN_THR; pr_debug("TCP-LP: %05o|%5u|%5u|%15u|%15u|%15u\n", lp->flag, - tp->snd_cwnd, lp->remote_hz, lp->owd_min, lp->owd_max, + tcp_snd_cwnd(tp), lp->remote_hz, lp->owd_min, lp->owd_max, lp->sowd >> 3); if (lp->flag & LP_WITHIN_THR) @@ -313,12 +313,12 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample) /* happened within inference * drop snd_cwnd into 1 */ if (lp->flag & LP_WITHIN_INF) - tp->snd_cwnd = 1U; + tcp_snd_cwnd_set(tp, 1U); /* happened after inference * cut snd_cwnd into half */ else - tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U); + tcp_snd_cwnd_set(tp, max(tcp_snd_cwnd(tp) >> 1U, 1U)); /* record this drop time */ lp->last_drop = now; |