From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C5D3C2C3259 for ; Sat, 18 Apr 2026 18:13:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776536041; cv=none; b=lpqBlesMLM3sE5urQU/3YFBMYsxl10YuZvSv+RZtogc0iOdupO5I0VVNcPj7jZiwNS05iqlP7PTf1UH5jmCSSo5yukxP+n2lfMJpa8XhtHT4/h4PoO1NpQf901nVycVD3o8an4av3vwLFIb3Um7ZRb2qi5XwJg6TXxg15f4uMFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776536041; c=relaxed/simple; bh=usACHL7JFJ+Iojq2WMGOR+XEp5pZozfvJwRKATA+b/g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cT5gBYDVPLXIzOpk9ZTA3Dvuug/vTulY2N1P9lS7iyCbpGD8yOWEcaF9q9Bo8QnXXD7W1dEZSZhH3x0Xok/WOY6YY6X7sdvKZp7CtI3qx3q9IkV+226XKsxKlT9l/fFntg64ZzM9fvZAUlVAk6FZr3GV0cUtAQ/i0gREAGMzwZU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IU0QsECp; arc=none smtp.client-ip=209.85.210.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IU0QsECp" Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-82f68b3aaf7so620598b3a.0 for ; Sat, 18 Apr 2026 11:13:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776536039; x=1777140839; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2qCHQt+5njpxpDnHvEMfTt2VrNOBnIxuj1+x6opPunc=; b=IU0QsECpAAiIVvNubSknYTQ4142KJvFFTxblP+0la2iD2AePiIK+V4TSAgNOx1bihu DWvTfc2YRjcKIGHXV38X78IMzLQfEasQc44j9POU0YSrYO9k1SttNj75r/NNul5sV6JG 8Cr25l4GxFH3lDwAcQB3r8wWxZXTtJG0X3Fura4VMA0FDYsUmE2Pje4HYaIxZ77C627w gNOEXZZP8AtFZD7NM3zjl5WD8KxRdloxDWc652YqVXBkLO+LCRPTIhdTjMZhX4HoEbky oh8eiufk7LQfKLPYs2r2pQP3szqdAnDJbTJb0Xgp+q5jC2Wh9A8tXq/Fm5RXFFBVCUCf U4QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776536039; x=1777140839; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=2qCHQt+5njpxpDnHvEMfTt2VrNOBnIxuj1+x6opPunc=; b=nTyapzxZAETnC+LtkSyqgnH3N33X3Zia8vci+jdYDw07V7UgbEA/KX8LggTJ28ggG+ skwcW3nue4ck9IEysXoHzhLdw6Yak8jsSyW2J5CI9O1bkLBylDEc58q4Fe/HFvhhyPap HH3ZEF1SPfcxTxYsn0AAx8+7t0NPBGHds17Cfu27M2221DMhMVTga0x19BMbbKU9s/Xg 1mwDo36dvnp6fw1XSAPmqqeYq+TJMpyO76Mrc+rrq2+BpOREusKhXqgLruoTiRxeQQK2 cZmIXEXz4hSMkDtd6J3eE7o3+ws7tRjDeOGNncoso/e7sRqjLmMdkJpWasK6ATXGDX3b msMA== X-Forwarded-Encrypted: i=1; AFNElJ8KboUs+d1aaqIFjW8+c5ZZDjrJQBdk2lT6u63j03IIKZ6f2KLVo7mOXJv/cFywgCxo3nMdV8c=@vger.kernel.org X-Gm-Message-State: AOJu0YwWKrmwDDwvc743mVH7zF+hykitziK33VGSX+IgcqjzmqKdULOK B4fs2QzuUjtneUsiyixftKUj3Mqh3xOgC7v5hnA6pr3IWiFvsXkj7B2K X-Gm-Gg: AeBDiev0qyfW/8O0yDlm6VQMKrpXTHz4lUBM1JOhXt5RtG/SZpmDZ5vPj6eKk2FnDzu vWeYMAeQUMG3FGRiDiimeLIFVewYifWdqYOvhTV9pZdyN6f4lmB2uXzjk/tvJJEou13+GbVBT8q 4ojbG7u2Q24NVHkHFjn5WgH6BZTAcfmth4nQE8qzW7VE/pPhLsIKsH8z1Gv8u/Vlr70uz/pRfbg q9SoT50DDVzkq9Bj+pzom87vP5lkTdX/ucHJ+ywKbFfaVon6xHDhAuYYSmV605pBP9NpMnT41BN glBgD5/VXazRUnIhMxkJlYlXNo02CLX9X09xqZ/qPqb8vsgyEm3BGEPAhYWMgJ6TD9vMvcaYIis 7v248XY1jhb8GutQx5BirfRD2WVuzpxY0T6Kxr8eG99Q3tMFCCsEISZD6mfba80HJusXfcjQNWF nSHoNIdzmNBJIQk5CsswXqeIWc0j4hv2WhCh8Gj3dj5KhimcCX3tUfStPWMX9iXg== X-Received: by 2002:a05:6a00:3397:b0:82a:6852:559e with SMTP id d2e1a72fcca58-82f8c82165amr8311427b3a.12.1776536039025; Sat, 18 Apr 2026 11:13:59 -0700 (PDT) Received: from DESKTOP-MUHC17F.tail07b66e.ts.net ([188.253.121.151]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82f8e9f7735sm5659402b3a.21.2026.04.18.11.13.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Apr 2026 11:13:58 -0700 (PDT) From: Zhenzhong Wu To: netdev@vger.kernel.org Cc: edumazet@google.com, ncardwell@google.com, kuniyu@google.com, davem@davemloft.net, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, shuah@kernel.org, tamird@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Zhenzhong Wu , stable@vger.kernel.org Subject: [PATCH net v2 1/2] tcp: call sk_data_ready() after listener migration Date: Sun, 19 Apr 2026 02:13:32 +0800 Message-ID: <20260418181333.1713389-2-jt26wzz@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260418181333.1713389-1-jt26wzz@gmail.com> References: <20260418181333.1713389-1-jt26wzz@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When inet_csk_listen_stop() migrates an established child socket from a closing listener to another socket in the same SO_REUSEPORT group, the target listener gets a new accept-queue entry via inet_csk_reqsk_queue_add(), but that path never notifies the target listener's waiters. A nonblocking accept() still works because it checks the queue directly, but poll()/epoll_wait() waiters and blocking accept() callers can also remain asleep indefinitely. Call READ_ONCE(nsk->sk_data_ready)(nsk) after a successful migration in inet_csk_listen_stop(). However, after inet_csk_reqsk_queue_add() succeeds, the ref acquired in reuseport_migrate_sock() is effectively transferred to nreq->rsk_listener. Another CPU can then dequeue nreq via accept() or listener shutdown, hit reqsk_put(), and drop that listener ref. Since listeners are SOCK_RCU_FREE, wrap the post-queue_add() dereferences of nsk in rcu_read_lock()/rcu_read_unlock(), which also covers the existing sock_net(nsk) access in that path. The reqsk_timer_handler() path does not need the same changes for two reasons: half-open requests become readable only after the final ACK, where tcp_child_process() already wakes the listener; and once nreq is visible via inet_ehash_insert(), the success path no longer touches nsk directly. Fixes: 54b92e841937 ("tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues.") Cc: stable@vger.kernel.org Suggested-by: Eric Dumazet Signed-off-by: Zhenzhong Wu --- net/ipv4/inet_connection_sock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 4ac3ae1bc..928654c34 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -1479,16 +1479,19 @@ void inet_csk_listen_stop(struct sock *sk) if (nreq) { refcount_set(&nreq->rsk_refcnt, 1); + rcu_read_lock(); if (inet_csk_reqsk_queue_add(nsk, nreq, child)) { __NET_INC_STATS(sock_net(nsk), LINUX_MIB_TCPMIGRATEREQSUCCESS); reqsk_migrate_reset(req); + READ_ONCE(nsk->sk_data_ready)(nsk); } else { __NET_INC_STATS(sock_net(nsk), LINUX_MIB_TCPMIGRATEREQFAILURE); reqsk_migrate_reset(nreq); __reqsk_free(nreq); } + rcu_read_unlock(); /* inet_csk_reqsk_queue_add() has already * called inet_child_forget() on failure case. -- 2.43.0