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From:   Kuniyuki Iwashima <kuniyu@amazon.com>
To:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Martin KaFai Lau <martin.lau@kernel.org>
CC:     Craig Gallek <kraig@google.com>,
        Willem de Bruijn <willemb@google.com>,
        Kuniyuki Iwashima <kuniyu@amazon.com>,
        Kuniyuki Iwashima <kuni1840@gmail.com>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v1 net 0/3] soreuseport: Fix issues related to the faster selection algorithm.
Date:   Mon, 10 Oct 2022 10:43:48 -0700
Message-ID: <20221010174351.11024-1-kuniyu@amazon.com>
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setsockopt(SO_INCOMING_CPU) for UDP/TCP is broken since 4.5/4.6 due to
these commits:

  * e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
  * c125e80b8868 ("soreuseport: fast reuseport TCP socket selection")

These commits introduced the O(1) socket selection algorithm and removed
O(n) iteration over the list, but it ignores the score calculated by
compute_score().  As a result, it caused two misbehaviours:

  * Unconnected sockets receive packets sent to connected sockets
  * SO_INCOMING_CPU does not work

The former is fixed by commit acdcecc61285 ("udp: correct reuseport
selection with connected sockets"), but it introduced a rare race,
which the first patch fixes.  The second patch fixes the latter, and
the third adds a test for SO_INCOMING_CPU.


Kuniyuki Iwashima (3):
  udp: Update reuse->has_conns under reuseport_lock.
  soreuseport: Fix socket selection for SO_INCOMING_CPU.
  selftest: Add test for SO_INCOMING_CPU.

 include/net/sock_reuseport.h                  |  25 ++-
 net/core/sock.c                               |   5 +-
 net/core/sock_reuseport.c                     |  88 ++++++++++-
 net/ipv4/datagram.c                           |   2 +-
 net/ipv4/udp.c                                |   2 +-
 net/ipv6/datagram.c                           |   2 +-
 net/ipv6/udp.c                                |   2 +-
 tools/testing/selftests/net/.gitignore        |   1 +
 tools/testing/selftests/net/Makefile          |   1 +
 tools/testing/selftests/net/so_incoming_cpu.c | 148 ++++++++++++++++++
 10 files changed, 260 insertions(+), 16 deletions(-)
 create mode 100644 tools/testing/selftests/net/so_incoming_cpu.c

-- 
2.30.2