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 7DA0514F9E7; Sun, 24 Mar 2024 23:18:39 +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=1711322319; cv=none; b=e0QFm5EPGPDDS/gE0skMV6SDZ2Sjfi6dhS9ln06bl0wqQP++8pT/tq4OsbbVcJsGhNzyEAaaHn/K/VOreMWdKHuMFx92dBephh+nAk1E26Lb1Yft5gUVa3MNwJmrIJ4JMpms0hAwtgWUetl/drZDNSlGD1geCcMEDfS/bL0hIEA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711322319; c=relaxed/simple; bh=KuuMt4zo3oLS5JZnEbW5U6AfANjVJ7GS1da+dy89Zyc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lhG2HJ+5Yp+9YnGb8eRBtYjwcFWYgeNGvEnU/rFMOEjJW+wWU2x9nUmgki3jQThrJun/tLE9QaqvPqVuW510TlZOSKAFvmN48MzxRCBAkxYk2jtBRv993zMvdAVD3rzO3X395CbJhfb/zM70gVO5BzkABoR04HBYruGY/wUWlX8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iC9zsp5Q; 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="iC9zsp5Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEC9DC43394; Sun, 24 Mar 2024 23:18:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711322319; bh=KuuMt4zo3oLS5JZnEbW5U6AfANjVJ7GS1da+dy89Zyc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iC9zsp5QG0tFxQ1CBCCg5fZexC+hiJykz+qXyM5jj1NiaTBpbre2Wtk4dTrA2N8Ko viagwNX28cM+H3HiKuTueJIQZE90J6N9p4u4ekUqfNZLbO3dSqP5ndL4w+du5U11/c 6ogMI9M3EKp4u89T8udDcQxSDVrPuF6BVL1oqCArDa/es4Jnc0Too0smZhyX3mRIFQ rCH5uGm2NbJmnlXC2UzgYZ0PXmLU09RAsEZps9O7r/Kl5sf7Ev0dEjFN7IhAlVjBhh LGLBgKt8KRIx90OWcp8cYfpfcIb+DNALnTIeItfJ9O3UB1pBYPm7XquWuybQzeJL6v hg0JRZs3aLw6A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 402/451] tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge() Date: Sun, 24 Mar 2024 19:11:18 -0400 Message-ID: <20240324231207.1351418-403-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324231207.1351418-1-sashal@kernel.org> References: <20240324231207.1351418-1-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: 8bit 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_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 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 1d77d992e6e77..340a8f0c29800 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -281,12 +281,12 @@ 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]; @@ -295,38 +295,35 @@ 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)->ns.count)) + if (sk->sk_family != family || + refcount_read(&sock_net(sk)->ns.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)->ns.count))) { - inet_twsk_put(tw); + if (unlikely(sk->sk_family != family || + refcount_read(&sock_net(sk)->ns.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; } -- 2.43.0