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 5F46C32D42B; Sat, 30 May 2026 16:55:24 +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=1780160125; cv=none; b=LW9lIq+M5zzmuw7ySdlJydwiV9Aq4aJBvZM2jRj966y/DFH6V+4BoLBP5IXSwj1eMC5Ncy8fgWzN3dXD1zqztRVzl+lK0CARD6qePJF4QmLcIRoAmA0t9waqOaGUpRh0EIIUo2rPq2xzK/L25wanwcpqiSE0NLt/YhXKpsV16NE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780160125; c=relaxed/simple; bh=LKOsiptLFBqj99yUXIWEninQOGVn4X2emxXKqp3MCqc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bCETzNwGhcsjqFOenyiUOqQPDx7SvouErZ61EC++kuh06XByAsSVGS1jatZza9BkO4EEMsQEjHAY466mqFU/K8ySLBOT0+4A2utYRI4g1aWA/4ME42RklMjFJFrAYvHWBd0OoT4wXZBfwQZkgUzeJxr3+P/WCap4DP0v2/j1PfY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hipx+y1o; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hipx+y1o" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F6401F00893; Sat, 30 May 2026 16:55:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780160124; bh=Obib9rezElJJKtKckU6HF4/Ji0Y+0UVXzQNtOUkGyik=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hipx+y1o8O5c7jO3SnRScZmcyY00PUD33msS1mijwAdCQ7q+WPA478EY1yHuOMEY2 yqx0L/anWkUcfdugj+UnqjqE+Aa3TAF8T0Va0lY6KKBNSI+UqGh8Dlm54o623qhIIB y0iNk3P29pCnoXeAEnJh6LAc3p3499hXRoVuHC8c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Kuniyuki Iwashima , Zhenzhong Wu , Jakub Kicinski Subject: [PATCH 6.1 251/969] tcp: call sk_data_ready() after listener migration Date: Sat, 30 May 2026 17:56:15 +0200 Message-ID: <20260530160307.399451429@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhenzhong Wu commit 3864c6ba1e041bc75342353a70fa2a2c6f909923 upstream. 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 Reviewed-by: Kuniyuki Iwashima Signed-off-by: Zhenzhong Wu Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260422024554.130346-2-jt26wzz@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_connection_sock.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -1429,16 +1429,19 @@ void inet_csk_listen_stop(struct sock *s 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.