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| author | Eric Dumazet <edumazet@google.com> | 2022-04-06 01:35:38 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-04-06 21:05:41 +0200 |
| commit | 40570375356c874b1578e05c1dcc3ff7c1322dbe (patch) | |
| tree | 54c7a52bfdd4e302f877e93dc94adb09cfa3aac4 /net/ipv4/tcp_dctcp.c | |
| parent | ip6_tunnel: Remove duplicate assignments (diff) | |
| download | linux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.xz 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_dctcp.c')
| -rw-r--r-- | net/ipv4/tcp_dctcp.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c index 1943a6630341..ab034a4e9324 100644 --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -106,8 +106,8 @@ static u32 dctcp_ssthresh(struct sock *sk) struct dctcp *ca = inet_csk_ca(sk); struct tcp_sock *tp = tcp_sk(sk); - ca->loss_cwnd = tp->snd_cwnd; - return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->dctcp_alpha) >> 11U), 2U); + ca->loss_cwnd = tcp_snd_cwnd(tp); + return max(tcp_snd_cwnd(tp) - ((tcp_snd_cwnd(tp) * ca->dctcp_alpha) >> 11U), 2U); } static void dctcp_update_alpha(struct sock *sk, u32 flags) @@ -148,8 +148,8 @@ static void dctcp_react_to_loss(struct sock *sk) struct dctcp *ca = inet_csk_ca(sk); struct tcp_sock *tp = tcp_sk(sk); - ca->loss_cwnd = tp->snd_cwnd; - tp->snd_ssthresh = max(tp->snd_cwnd >> 1U, 2U); + ca->loss_cwnd = tcp_snd_cwnd(tp); + tp->snd_ssthresh = max(tcp_snd_cwnd(tp) >> 1U, 2U); } static void dctcp_state(struct sock *sk, u8 new_state) @@ -211,8 +211,9 @@ static size_t dctcp_get_info(struct sock *sk, u32 ext, int *attr, static u32 dctcp_cwnd_undo(struct sock *sk) { const struct dctcp *ca = inet_csk_ca(sk); + struct tcp_sock *tp = tcp_sk(sk); - return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd); + return max(tcp_snd_cwnd(tp), ca->loss_cwnd); } static struct tcp_congestion_ops dctcp __read_mostly = { |