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| author | Paolo Abeni <pabeni@redhat.com> | 2026-02-03 19:41:17 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-02-04 18:45:08 -0800 |
| commit | 6b329393502e5857662b851a13f947209c588587 (patch) | |
| tree | 841abe182a13a4aa2ec6cd35213eb9dd2fd615d2 /net/mptcp | |
| parent | e25dbf561e03c0c5e36228e3b8b784392819ce85 (diff) | |
| download | lwn-6b329393502e5857662b851a13f947209c588587.tar.gz lwn-6b329393502e5857662b851a13f947209c588587.zip | |
mptcp: do not account for OoO in mptcp_rcvbuf_grow()
MPTCP-level OoOs are physiological when multiple subflows are active
concurrently and will not cause retransmissions nor are caused by
drops.
Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly
drifting towards tcp_rmem[2].
Remove such accounting. Note that subflows will still account for TCP-level
OoO when the MPTCP-level rcvbuf is propagated.
This also closes a subtle and very unlikely race condition with rcvspace
init; active sockets with user-space holding the msk-level socket lock,
could complete such initialization in the receive callback, after that the
first OoO data reaches the rcvbuf and potentially triggering a divide by
zero Oops.
Fixes: e118cdc34dd1 ("mptcp: rcvbuf auto-tuning improvement")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-1-31ec8bfc56d1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp')
| -rw-r--r-- | net/mptcp/protocol.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 9b8c51937eb2..758a6dcb1d7b 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -224,9 +224,6 @@ static bool mptcp_rcvbuf_grow(struct sock *sk, u32 newval) do_div(grow, oldval); rcvwin += grow << 1; - if (!RB_EMPTY_ROOT(&msk->out_of_order_queue)) - rcvwin += MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq - msk->ack_seq; - cap = READ_ONCE(net->ipv4.sysctl_tcp_rmem[2]); rcvbuf = min_t(u32, mptcp_space_from_win(sk, rcvwin), cap); @@ -350,9 +347,6 @@ merge_right: end: skb_condense(skb); skb_set_owner_r(skb, sk); - /* do not grow rcvbuf for not-yet-accepted or orphaned sockets. */ - if (sk->sk_socket) - mptcp_rcvbuf_grow(sk, msk->rcvq_space.space); } static void mptcp_init_skb(struct sock *ssk, struct sk_buff *skb, int offset, |