From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5851C58FD1D; Tue, 8 Sep 2026 17:25:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788888359; cv=none; b=osPuUEpH4YgZ4iUXSCcO63Xd1yU2XzZeraEICPzKoLqY3FJLnDzs6K7wiwasi6U8sGx+3UokZornMJCQNF59gbogxJMjVflVCzs/EmgXVub+DXKdOrmWkUo+ZZ76A0mi/o+J7afxeh8mA6AHDGMZs6yiwhvNZQ55FaJ2Y32iLaQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788888359; c=relaxed/simple; bh=KV+P1GR5UC9sJ0F+5QY1pcXLH4BWW4rPFQTylAnrHpY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y9xshNQ+GA9B76Nj6h0nswQ6QZ7aH0VA8FI9vwwWTkr3PUVND7qPaojvWCk97SBuANQYPqaR4NPzmvkeWF58KVs1XBWsU1WaTLkm6ts3nUgJrOCKvhyaBjkwHmAxrfJKqFW5lSawzxw4RD2SsSksZb39V4Xd02yGbCFyEauknYY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZD+IPPTd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZD+IPPTd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EBC11F00A3A; Tue, 8 Sep 2026 17:25:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788888358; bh=nScoxQtdxykKU9QZOPMgNZaJVcGJcoE6oBnNk2LcKH4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ZD+IPPTdaHsyN1+Rt6vgGjcGaTkRi5iZfksMqNBL3XwnEaLW/TB7QwEHrWH4Rdg9+ U4Xfu02g6fNnXi9N6jsC4fVnSoykBdLEXu31+uXN0GI+EML0+6qkwFMMWJ/ZdyivP2 +ngE8A9dG4NENHyZukoZuVqKeLCbUgYSCpLTuATcux/AeLW/7rAachagGUWEZ8Gao7 eh8DMixyRxZ78ytFFaVk7/F/8jx2U/BvkII7h14glZR9sRr7DBdyaZwtbb2HQIRBWR Fzj7DXhDroa4CKw/W0hNAuldGsjqv/eL+UGIrcBpS36J6zkTM1nuwF2vbFoIqUSuwG T/ZiKjk1J7mXw== Message-ID: Date: Tue, 8 Sep 2026 19:25:53 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net] tcp: fix data-race in tcp_recv_should_stop Content-Language: fr To: quanyeyang@proton.me, Eric Dumazet , Neal Cardwell , Kuniyuki Iwashima , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Geliang Tang , Mat Martineau Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260908-mptcp-sk-err-net-v1-1-da71aaec9afd@proton.me> 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: <20260908-mptcp-sk-err-net-v1-1-da71aaec9afd@proton.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Quanye, Thank you for this patch. On 08/09/2026 04:59, Quanye Yang via B4 Relay wrote: > From: Quanye Yang > > BUG: KCSAN: data-race in do_recvmmsg / mptcp_recvmsg > > read-write (marked) to 0xffff8880134d391c of 4 bytes by task 2619 on cpu 1: > instrument_atomic_read_write include/linux/instrumented.h:113 [inline] > sock_error include/net/sock.h:2565 [inline] > do_recvmmsg+0x50c/0x580 net/socket.c:3049 > __sys_recvmmsg net/socket.c:3144 [inline] > __do_sys_recvmmsg net/socket.c:3167 [inline] > __se_sys_recvmmsg net/socket.c:3160 [inline] > __x64_sys_recvmmsg+0x161/0x180 net/socket.c:3160 > x64_sys_call+0x19c7/0x1ca0 arch/x86/include/generated/asm/syscalls_64.h:300 > do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] > do_syscall_64+0xde/0x3d0 arch/x86/entry/syscall_64.c:84 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > read to 0xffff8880134d391c of 4 bytes by task 2620 on cpu 0: > tcp_recv_should_stop include/net/tcp.h:3086 [inline] > mptcp_recvmsg+0x54d/0xd50 net/mptcp/protocol.c:2466 > inet_recvmsg+0x204/0x210 net/ipv4/af_inet.c:894 > sock_recvmsg_nosec net/socket.c:1151 [inline] > sock_recvmsg+0x11a/0x140 net/socket.c:1173 > ____sys_recvmsg+0x14b/0x3c0 net/socket.c:2933 > ___sys_recvmsg+0x116/0x160 net/socket.c:2975 > __sys_recvmsg net/socket.c:3008 [inline] > __do_sys_recvmsg net/socket.c:3014 [inline] > __se_sys_recvmsg net/socket.c:3011 [inline] > __x64_sys_recvmsg+0xeb/0x160 net/socket.c:3011 > x64_sys_call+0x1319/0x1ca0 arch/x86/include/generated/asm/syscalls_64.h:48 > do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] > do_syscall_64+0xde/0x3d0 arch/x86/entry/syscall_64.c:84 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > value changed: 0x0000006b -> 0x00000000 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 0 UID: 0 PID: 2620 Comm: syz.2.33 Not tainted 7.2.0-g39d4f32c5d53 #76 PREEMPT(full) > Hardware name: QEMU Ubuntu 26.04 PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1ubuntu1 04/01/2014 Just to avoid some confusions, this has been reported by MPTCP syzkaller instances, not by Syzbot. So just not to have people trying to get more details on the wrong website: Reported-by: Matthieu Baerts (NGI0) Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/632 Cheers, Matt -- Sponsored by the NGI0 Core fund.