From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Cc: "David S . Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Craig Gallek <kraig@google.com>, Paolo Abeni <pabeni@redhat.com>,
Network Development <netdev@vger.kernel.org>,
Kuniyuki Iwashima <kuni1840@gmail.com>,
Benjamin Herrenschmidt <benh@amazon.com>,
osa-contribution-log@amazon.com
Subject: Re: [PATCH net 1/2] udp: Copy has_conns in reuseport_grow().
Date: Tue, 21 Jul 2020 08:25:04 -0400 [thread overview]
Message-ID: <CA+FuTSeWNarNvhPeg4Z-97Xsz_7H1WvW6NshC7VLnVwECxLqfw@mail.gmail.com> (raw)
In-Reply-To: <20200721061531.94236-2-kuniyu@amazon.co.jp>
On Tue, Jul 21, 2020 at 2:16 AM Kuniyuki Iwashima <kuniyu@amazon.co.jp> wrote:
>
> If an unconnected socket in a UDP reuseport group connect()s, has_conns is
> set to 1. Then, when a packet is received, udp[46]_lib_lookup2() scans all
> sockets in udp_hslot looking for the connected socket with the highest
> score.
>
> However, when the number of sockets bound to the port exceeds max_socks,
> reuseport_grow() resets has_conns to 0. It can cause udp[46]_lib_lookup2()
> to return without scanning all sockets, resulting in that packets sent to
> connected sockets may be distributed to unconnected sockets.
>
> Therefore, reuseport_grow() should copy has_conns.
>
> Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
> CC: Willem de Bruijn <willemb@google.com>
> Reviewed-by: Benjamin Herrenschmidt <benh@amazon.com>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Willem de Bruijn <willemb@google.com>
Thanks. Yes, I missed this resize operation when adding the field.
next prev parent reply other threads:[~2020-07-21 12:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 6:15 [PATCH net 0/2] udp: Fix reuseport selection with connected sockets Kuniyuki Iwashima
2020-07-21 6:15 ` [PATCH net 1/2] udp: Copy has_conns in reuseport_grow() Kuniyuki Iwashima
2020-07-21 12:25 ` Willem de Bruijn [this message]
2020-07-21 6:15 ` [PATCH net 2/2] udp: Improve load balancing for SO_REUSEPORT Kuniyuki Iwashima
2020-07-21 12:33 ` Willem de Bruijn
2020-07-21 22:32 ` [PATCH net 0/2] udp: Fix reuseport selection with connected sockets David Miller
2020-07-22 4:28 ` Kuniyuki Iwashima
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