From nobody Fri Dec 19 18:42:50 2025 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 AD98C21D158; Sun, 24 Mar 2024 23:10:52 +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=1711321852; cv=none; b=Kg0pVODsig+jfFB+fEtdFhf5+r6uivZrJfY2NYATNfIExl3JgC5+SbAz2OFb33JJA19fToE/u921/fNvUu8rQGFo4hfvRlTpHKFepR6ti5q2B9KZbHLpjlFljYtpDXu3a/kKOqiQmkFtEczZNJZm1OqQDnkw9rFDPj3/0JaHy74= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321852; c=relaxed/simple; bh=B8oGi9dfAaBRt2j+HYNsW/8VQ3WhUGEvKoxAv6ORkPs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uQ1SXOeroI9AQH7bOrJXEZM3xbhVKXdMYk/V/4wXtWf27C4cmoRulWBPXUwQ/Kef1+JKLp/2hXTV7QlCQFKy/ifJPbKlNsyVG0bDv41bpIaR4p6I7yOASgb3FWXNdZ/dpdoip/Ii3SiDsZL2DTs+e78KcezShIoCx9wVoEdXEyI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XtGCfsp+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XtGCfsp+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC22DC433C7; Sun, 24 Mar 2024 23:10:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321852; bh=B8oGi9dfAaBRt2j+HYNsW/8VQ3WhUGEvKoxAv6ORkPs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XtGCfsp+YQ3dCWqKnprR2QJAmywjLJi6CFi1QSJ2vDz5VZc8rAlIlRBnI31Y7+i31 a59piuawT57hDHULfFDmAFHjp5WGPDc5TcyeUkdvQQ53X1jr+b3bRxsqovMbiHWSAC DF4vmhWPWfcs72gpB1aCBgWr8ZZQmLT00ncUA6GGRungg9AycoD54Hanc5nLmelcUM 4+I2nQF1ugsm7qcSNFGp/HmpIdDO58I/QS9fgerQUGMcl4DBO3LAaf1KjkajZT18w7 H8r34eNk3/IrK3T4nUUe4IDCl6xLZDwJFhyDXa7whZq9j4LqSqMWbEBBV/UxiWSCh9 8WqetckqFSnJw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 581/638] tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge() Date: Sun, 24 Mar 2024 19:00:18 -0400 Message-ID: <20240324230116.1348576-582-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324230116.1348576-1-sashal@kernel.org> References: <20240324230116.1348576-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Eric Dumazet [ Upstream commit 1c4e97dd2d3c9a3e84f7e26346aa39bc426d3249 ] 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_pu= rge()") Link: https://lore.kernel.org/netdev/CANn89iLvFuuihCtt9PME2uS1WJATnf5fKjDTo= a1WzVnRzHnPfg@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 Signed-off-by: Sasha Levin --- 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 dd37a5bf68811..757ae3a4e2f1a 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -278,12 +278,12 @@ void __inet_twsk_schedule(struct inet_timewait_sock *= tw, int timeo, bool rearm) } EXPORT_SYMBOL_GPL(__inet_twsk_schedule); =20 +/* 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; =20 for (slot =3D 0; slot <=3D hashinfo->ehash_mask; slot++) { struct inet_ehash_bucket *head =3D &hashinfo->ehash[slot]; @@ -292,38 +292,35 @@ 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 !=3D 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 =3D=3D TCP_NEW_SYN_RECV && - hashinfo->pernet)) { - struct request_sock *req =3D inet_reqsk(sk); - - inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req); - } + int state =3D inet_sk_state_load(sk); =20 + if ((1 << state) & ~(TCPF_TIME_WAIT | + TCPF_NEW_SYN_RECV)) continue; - } =20 - tw =3D inet_twsk(sk); - if ((tw->tw_family !=3D family) || - refcount_read(&twsk_net(tw)->ns.count)) + if (sk->sk_family !=3D family || + refcount_read(&sock_net(sk)->ns.count)) continue; =20 - if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt))) + if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) continue; =20 - if (unlikely((tw->tw_family !=3D family) || - refcount_read(&twsk_net(tw)->ns.count))) { - inet_twsk_put(tw); + if (unlikely(sk->sk_family !=3D family || + refcount_read(&sock_net(sk)->ns.count))) { + sock_gen_put(sk); goto restart; } =20 rcu_read_unlock(); local_bh_disable(); - inet_twsk_deschedule_put(tw); + if (state =3D=3D TCP_TIME_WAIT) { + inet_twsk_deschedule_put(inet_twsk(sk)); + } else { + struct request_sock *req =3D inet_reqsk(sk); + + inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, + req); + } local_bh_enable(); goto restart_rcu; } --=20 2.43.0