From patchwork Mon Apr 29 12:32:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: shaozhengchao X-Patchwork-Id: 13646872 X-Patchwork-Delegate: kuba@kernel.org Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (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 1D5C554743; Mon, 29 Apr 2024 12:27:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714393632; cv=none; b=FJROaHoIAEF8FwobE6awWUyImz4ksFSrLQ8vPKUtpz11x2AgLezmSzIGKOZs9szxHmG8br2X0ZyzQiHvtuWrojUV/6sqQxRhOfmlFvLRBm21rBhJaT+f1sV5DvIb35jHyVl0hsXozOYzPOkaUP8hZ1WCitB3UsNcbMzGIIDHSKo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714393632; c=relaxed/simple; bh=dUle5HSqtreqdGJVBgZoTRHHb/1VpgMrIKybSKN1NcM=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ZQY1ngZVS+Ho/MwkIdh+VilHT6jqQcdf5NfgQTY7C0CkaiBYvhuqDvo6sU5Nav+YwnGAEPs4LgawosKq+HJjlPhg9mIydgCCh/AqmtVUAt5ambJTR+tnCaPUVC4NFBunU8MsxzSCd4MWT71OW2e2tUVjmOcNvLPdUqUrln2FVCM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4VSjDb5HnQz1R9pq; Mon, 29 Apr 2024 20:23:59 +0800 (CST) Received: from dggpeml500026.china.huawei.com (unknown [7.185.36.106]) by mail.maildlp.com (Postfix) with ESMTPS id DF86C18007D; Mon, 29 Apr 2024 20:27:07 +0800 (CST) Received: from huawei.com (10.175.101.6) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Mon, 29 Apr 2024 20:27:07 +0800 From: Zhengchao Shao To: CC: , , , , , , , , , , Subject: [PATCH stable,4.19 2/2] tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge() Date: Mon, 29 Apr 2024 20:32:24 +0800 Message-ID: <20240429123224.2730596-3-shaozhengchao@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240429123224.2730596-1-shaozhengchao@huawei.com> References: <20240429123224.2730596-1-shaozhengchao@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500026.china.huawei.com (7.185.36.106) X-Patchwork-Delegate: kuba@kernel.org 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 --- net/ipv4/inet_timewait_sock.c | 41 ++++++++++++++++------------------- 1 file changed, 19 insertions(+), 22 deletions(-) diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c index 0ab4e0e28baf..fc01efef980a 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -253,12 +253,12 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm) } 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 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family) 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; }