From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D11D73DE452; Mon, 4 May 2026 14:16:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777904172; cv=none; b=quo2y2XHym5hyfyCVMPs7r0o7q2p9+d+g2oeuOp0d91ZHCON1p661xknpBW+H9GCYp+Ero4zBJQVI19y4DU3UrIALJr3AvyU4nCAhrNKwX4xT6hJrnyyPiI8BndtjKCRxAU040c8aiDvi0uyJpm2fLgTC8+RdDz+aGFpwu/jOE0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777904172; c=relaxed/simple; bh=Oyvf7cle/pRvxz6MY5eW9mpWSEjdZJ5IoWcGJsl8Arg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t2VkJitPoYoIFpwEuj9XNyq/zuJOxvUBdBq9eqUMc0ylnt2z/W7gWXX3RHwRsbHIOJqo8IzlFrRJPx8xewdD/2K1YVV29iI+TN0t/D5bOykjczPsARctwXEp+jyM5GF+23gx+XpLbqHIN1DVTHap3cYzxy1KjGJbhaZBgOtOlso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mfW1eNfc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mfW1eNfc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2445CC2BCF4; Mon, 4 May 2026 14:16:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777904172; bh=Oyvf7cle/pRvxz6MY5eW9mpWSEjdZJ5IoWcGJsl8Arg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mfW1eNfcUa8gYCHw9Bu14lcL2g2wObLx0LTBjD0KSOjS86GGZVHANdQUkXsNh2uqs QQ2GE1ClToM4UNPGw+cWpiw4y3g44y5ywLtKBY+YMaJK0DVwzCfNU6ZS8TrBKkTu80 z3rxzq4vNpzAf35c5ZoFlW8WwIMp0YAU+nvYKPa4= 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 6.18 212/275] tcp: call sk_data_ready() after listener migration Date: Mon, 4 May 2026 15:52:32 +0200 Message-ID: <20260504135150.950434406@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260504135142.929052779@linuxfoundation.org> References: <20260504135142.929052779@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-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 @@ -1486,16 +1486,19 @@ 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.