From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794338089; b=jcjvTPnmg6KhqBQ5pQaYElI3jY1gdjXuuBJQMvB8rexyiMoQWlqVDShYNeKAsNUip2h1 ItKwdQrCUs/WpWuAy5q4XcLPFXzIuPb8mx87KYRfywq5JPd2OXVsNdGUWY1rCFctxxbPi UI6E+uMPf33xnzNKNtz1gkxPIMF8shxDbRHQpYaBSRyROapDzyIDZv3TgUfHVhZsiYcr/ XJ+/1eiPSFieIZOcrpYqbGy+evy1WFilf8p9MylyJ6lXIpTHKRhFIuXE999LDb1Er08GG tqPUX1fg7Wl8/zQD24AQKnnEIimOpyja8yjck02kGrETJRJc5+BoacmniUhx5Mc/PCg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794338089; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:Content-Language:To:Cc:References:From:Autocrypt:Organization: In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=pplLshw7Vrx6M7DLcrIKGkU48GT/Xb5lGak8VdXg6mk=; b=TXNIWvwqGLu2N6LMVMktYS0dLEseDDPITdoJLqyaoc2GIbiEyifa94qrVD7FH/xAlHH/ jmUO9u4fKkZ6D3HMtB8kWlcBdk5a3+owq7lMNyFPhetB7IphfWn+m9EftsmHQsk/hvUQK S8pz3BMXul0+l0x74BkX0LjxVEhkuSUrhDh25iJur/LCK1RkNk9zKC+NGOllm2RPNVyPN izZ9gMNkfQyJY73js6fl64oxmXGm//VPG7SySUwm6pMu9YsoitzNaJR7Q2kEffWh9Bl64 5kwIJi+IUvrXpfPy0ENUZTRsEuASd7GYEv2/yvlnSlGmdibb1A5fGAznmIC7NxIlrnQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=B2pMIsdo; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD70B606A320 for ; Tue, 10 Nov 2026 19:14:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=B2pMIsdo Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94DD01F0089F; Tue, 10 Nov 2026 19:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794338088; bh=pplLshw7Vrx6M7DLcrIKGkU48GT/Xb5lGak8VdXg6mk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=B2pMIsdo/FYOfY08YER6BRcDO94TkABlP0Zt3TyG1aWVM8abcAa1/A0jqcW7W7Azc AT/UociGiXFk2ew1oQQaSOj5smRHjgTnH56qFffBwNz6puhk2Hti5i8CYGDi/ePtbu eaIZipHykke60uNrXZsA4GvFTWKbl4ZsNU1b+/7qSU/9i70TOw358gcVxziq0jqKKk sH+9+cM5Q8clAbLepEE/9svJTsAn4Taxdy3PH9eG8UuJmPtfFvlUxcSyLhEa3IF6mb 9gRMgJq90SEGMzC4izs47PbR/4E0BPRQsPH6Sd6Cutk9puMNaUHI6mHQEQ0iUdYpOG 7oS/uEbnKc0pg== Message-ID: <5c296ec6-c68e-4f70-91f9-1771afe300a4@kernel.org> Date: Tue, 10 Nov 2026 20:14:42 +0100 X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH v1 net 1/3] tcp: Clear DEFER_CONNECT before tcp_connect() and in tcp_abort(). Content-Language: fr To: Kuniyuki Iwashima Cc: Eric Dumazet , Neal Cardwell , "David S . Miller" , Jakub Kicinski , Paolo Abeni , Yuchung Cheng , Wei Wang , Mat Martineau , Geliang Tang , Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org References: <20261107235720.3129212-1-kuniyu@google.com> <20261107235720.3129212-2-kuniyu@google.com> <8362f907-4e8e-4514-bff6-f0bf8fd22f57@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 10/11/2026 20:12, Kuniyuki Iwashima wrote: > On Tue, Nov 10, 2026 at 10:46 AM Matthieu Baerts wrote: >> >> Hi Kuniyuki, >> >> On 08/11/2026 00:56, Kuniyuki Iwashima wrote: >>> When TFO is enabled, tcp_v[46]_connect() sets sk->sk_state to >>> TCP_SYN_SENT and puts the socket into ehash without calling >>> tcp_connect(). >>> >>> Then, tcp_fastopen_defer_connect() sets DEFER_CONNECT, and >>> the first write()/sendmsg() will call tcp_connect() and send >>> SYN with data if possible. >>> >>> If tcp_abort() kills a socket before the first write()/sendmsg(), >>> the unhashed socket can still call it and send SYN in TCP_CLOSE. >>> >>> Also, DEFER_CONNECT is cleared after __inet_stream_connect(). >>> >>> So, blocking write()/sendmsg() can release lock_sock() in >>> inet_wait_for_connect() while DEFER_CONNECT is set, and >>> tcp_poll() could set EPOLLOUT even after SYN is sent. >>> >>> Let's clear DEFER_CONNECT in tcp_abort() and right before >>> tcp_connect() in tcp_sendmsg_fastopen(). >> >> Thank you for the fix! >> >> It looks like we can still have the race with MPTCP: >> >> https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20261107235720.3129212-1-kuniyu%40google.com >> >> But that's not blocking this series here, so for the MPTCP part: >> >> Acked-by: Matthieu Baerts (NGI0) > > Thanks Matt ! > >> >> >> Just to avoid a deadlock, are you planning to fix the issue on MPTCP >> side as well? If not, I can look at that later on when I can. > > I would appreciate it if you could look into it. Sure, I will wait for this series to be applied first. Cheers, Matt -- Sponsored by the NGI0 Core fund.