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 C63B812C48B; Tue, 30 Apr 2024 10:44:37 +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=1714473877; cv=none; b=ROi13vhSqdLagTBDvNx3c+rqJU+dBOoJamukYKgf9DNQf9jQTFmfZm0dROF+/6PF3F1GbRpQZ2/Z07oRm0QQO4ebGNcZzHnvIPK9c49HkIAraQAHGYD5f/g5ivXilk19TVRDK504WhiBfeIw13A8IgKIoPMMHVyPUDm1jtM/LcQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714473877; c=relaxed/simple; bh=/w2t+z58a9kNf0phAeiTjhzQX6LiEtS8chgqQ94J434=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q8zF8VrnMikDOCoxRsU/NhJE3awi0EII53/1S3S+BVq2wwS68EpzQwM8+Mx/6TDsRDxaVez9cI5Yp5lRQNSOtcTwTuuN8VVNePrCXkZUyjudTschFuyAXINEw2U8dZXGr/sjnJo4kTfR8v8NLM94pbRx5jBc2cvsIDZoS0eKHNY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=w0Bswu2R; 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="w0Bswu2R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 479DCC2BBFC; Tue, 30 Apr 2024 10:44:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1714473877; bh=/w2t+z58a9kNf0phAeiTjhzQX6LiEtS8chgqQ94J434=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w0Bswu2R2oMBhTP+cy8Ath3f7aSE/Zu/YbanRK3Y8nAi3WTiKyHSvGQeyyHaH/nnt UfFoNeHnJN57UxV2wq5F1+U5vKLCuZ/vfRF3nAjhsocZZ4/b6mImFMFTh2vxUNJtKB RieL0EXd4uClR9w5b31H6U2F+Ic0zGzESJN9n8SM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Zhengchao Shao Subject: [PATCH 4.19 69/77] tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge() Date: Tue, 30 Apr 2024 12:39:48 +0200 Message-ID: <20240430103043.176513161@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240430103041.111219002@linuxfoundation.org> References: <20240430103041.111219002@linuxfoundation.org> User-Agent: quilt/0.67 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 1c4e97dd2d3c9a3e84f7e26346aa39bc426d3249 upstream. inet_twsk_purge() uses rcu to find TIME_WAIT and NEW_SYN_RECV objects to purge. These objects use SLAB_TYPESAFE_BY_RCU semantic and need special care. We need to use refcount_inc_not_zero(&sk->sk_refcnt). Reuse the existing correct logic I wrote for TIME_WAIT, because both structures have common locations for sk_state, sk_family, and netns pointer. If after the refcount_inc_not_zero() the object fields longer match the keys, use sock_gen_put(sk) to release the refcount. Then we can call inet_twsk_deschedule_put() for TIME_WAIT, inet_csk_reqsk_queue_drop_and_put() for NEW_SYN_RECV sockets, with BH disabled. Then we need to restart the loop because we had drop rcu_read_lock(). Fixes: 740ea3c4a0b2 ("tcp: Clean up kernel listener's reqsk in inet_twsk_purge()") Link: https://lore.kernel.org/netdev/CANn89iLvFuuihCtt9PME2uS1WJATnf5fKjDToa1WzVnRzHnPfg@mail.gmail.com/T/#u Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20240308200122.64357-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski [shaozhengchao: resolved conflicts in 5.10] Signed-off-by: Zhengchao Shao Signed-off-by: Greg Kroah-Hartman --- net/ipv4/inet_timewait_sock.c | 41 +++++++++++++++++++---------------------- 1 file changed, 19 insertions(+), 22 deletions(-) --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -253,12 +253,12 @@ void __inet_twsk_schedule(struct inet_ti } EXPORT_SYMBOL_GPL(__inet_twsk_schedule); +/* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family) { - struct inet_timewait_sock *tw; - struct sock *sk; struct hlist_nulls_node *node; unsigned int slot; + struct sock *sk; for (slot = 0; slot <= hashinfo->ehash_mask; slot++) { struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; @@ -267,38 +267,35 @@ restart_rcu: rcu_read_lock(); restart: sk_nulls_for_each_rcu(sk, node, &head->chain) { - if (sk->sk_state != TCP_TIME_WAIT) { - /* A kernel listener socket might not hold refcnt for net, - * so reqsk_timer_handler() could be fired after net is - * freed. Userspace listener and reqsk never exist here. - */ - if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV && - hashinfo->pernet)) { - struct request_sock *req = inet_reqsk(sk); - - inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req); - } + int state = inet_sk_state_load(sk); + if ((1 << state) & ~(TCPF_TIME_WAIT | + TCPF_NEW_SYN_RECV)) continue; - } - tw = inet_twsk(sk); - if ((tw->tw_family != family) || - refcount_read(&twsk_net(tw)->count)) + if (sk->sk_family != family || + refcount_read(&sock_net(sk)->count)) continue; - if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt))) + if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) continue; - if (unlikely((tw->tw_family != family) || - refcount_read(&twsk_net(tw)->count))) { - inet_twsk_put(tw); + if (unlikely(sk->sk_family != family || + refcount_read(&sock_net(sk)->count))) { + sock_gen_put(sk); goto restart; } rcu_read_unlock(); local_bh_disable(); - inet_twsk_deschedule_put(tw); + if (state == TCP_TIME_WAIT) { + inet_twsk_deschedule_put(inet_twsk(sk)); + } else { + struct request_sock *req = inet_reqsk(sk); + + inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, + req); + } local_bh_enable(); goto restart_rcu; }