From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590391; b=LgYyBP1KzDHUAlEsBXQXsIq03SI/6+Pw1dN1CKBw3SdImOsCtxGMsJOQJR5RPRllBcMu A0Abycq5Ab1Iqa9g6JfGOJYGu+fIfiL+XQwUyd2IaM4SWyT1NTO/+OWMw6Lmwij/nyawk jtGDfjhMB9CrM9izDhiScNHKhZsFmWsQQ4+aqXYd8Dg31UPHUnuxCLt5fS33Jauiu6AyW iw/WEhfypD49Si9ZrHoDfiC8W14s4Opu4Rx5K+XbTJXew1DRNOArwpDDfx6lMuvMmfDL+ R88l7dqyLpa0cGB4s8GG0RA7d7p7mUTlfiT+E83/8J4fmagHyY1FWVsWyBGxRcJDsvw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590391; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=ND3HEk20zLiRVZe3GCtw8OR6/MxQrVZgg0e258UlMVo=; b=c7ffq+5xTSnttvpJA50qWW8ehqjllfnRyU+HY8xhZOF37elA5r0knOLQMB8zbQ16f11Z bEuUj49fpKd05kh+pk2pPsmkiAsU06eTEgKLijQg3hlDaWVVK+n/ZIdygs8sKbiuT57ob sUC1WdDOJ46NqTKUqFqrII3dIKrfXR59p4CsYcYodS3BHffVlBam7zwiGBPezu6HHR1Uc OhFtPt1nTZaeB/dWrx7DYcAA0lPZlsDDfWEHzPOrSLsxIbc29uYsNFa67ij39nP0P5e6k DZcXj+P/MviUrhrlIR/9lG8jchtId4rzjtCQjn1CHSOf1BG3mrz4NwG20dieZHIWilA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zyLGCA7S; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1ECF606B443; Fri, 13 Nov 2026 17:19:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zyLGCA7S Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A2751F000C4; Fri, 13 Nov 2026 17:19:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590391; bh=ND3HEk20zLiRVZe3GCtw8OR6/MxQrVZgg0e258UlMVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zyLGCA7SJ6d//hbPGgubiiP/eMZJTmQ90YDZ9yPa7gFcebjoobpwT00naSFBwnRZY t5j8qvoSiQ7u8d3UHJzZHrFbOApq9fRgtDY/XXpDKHvVvGxPj3b/cK8zUNuxS4352B +EfYSKLXn77R4fL96DBtIdykYgAfwoT1gxN/txHE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hyunwoo Kim , Kuniyuki Iwashima , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 359/686] net: restore refcount ordering for lockless socket access Date: Fri, 13 Nov 2026 10:48:12 -0500 Message-ID: <20261113153833.071406418@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hyunwoo Kim [ Upstream commit 5b5d8f351dd96f56a58bb516a80e2d4d742fe4e2 ] Before commit fb041bb7c0a9 ("locking/refcount: Consolidate implementations of refcount_t"), default builds implemented refcount_inc_not_zero() using atomic_add_unless(), which provided full memory ordering on success. The commit removed that ordering on weakly ordered architectures, allowing accesses after a successful reference acquisition to be reordered before it. Use refcount_inc_not_zero_acquire() in the IPv4 and IPv6 established lookups and in inet_twsk_purge(), where the socket is validated again after taking a reference. bpf_sk_assign() can receive a socket pointer obtained through BTF without a reference. Use acquire ordering when it takes its own reference for a refcounted socket. Use refcount_set_release() when setting refcounts in the SYN cookie, TCP Fast Open, request migration, and TIME_WAIT paths. Keep the existing TIME_WAIT smp_wmb(), which separately orders the refcount store before ehash publication. Fixes: fb041bb7c0a9 ("locking/refcount: Consolidate implementations of refcount_t") Fixes: 27e5203bd9c5 ("bpf: Change bpf_sk_assign to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20261029214219.1035176-3-imv4bel@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/core/filter.c | 2 +- net/ipv4/inet_connection_sock.c | 6 +++--- net/ipv4/inet_hashtables.c | 2 +- net/ipv4/inet_timewait_sock.c | 4 ++-- net/ipv4/syncookies.c | 2 +- net/ipv4/tcp_fastopen.c | 2 +- net/ipv6/inet6_hashtables.c | 2 +- 7 files changed, 10 insertions(+), 10 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 6670b43cb640d..5c3c0939e2d20 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -7691,7 +7691,7 @@ BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags) if (sk_unhashed(sk)) return -EOPNOTSUPP; if (sk_is_refcounted(sk) && - unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) + unlikely(!refcount_inc_not_zero_acquire(&sk->sk_refcnt))) return -ENOENT; skb_orphan(skb); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index dd14944ad3edd..543a6f2d12dfc 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -1083,8 +1083,8 @@ static void reqsk_timer_handler(struct timer_list *t) * hold another count to prevent use-after-free and * call reqsk_put() just before return. */ - refcount_set(&nreq->rsk_refcnt, 2 + 1); timer_setup(&nreq->rsk_timer, reqsk_timer_handler, TIMER_PINNED); + refcount_set_release(&nreq->rsk_refcnt, 2 + 1); reqsk_queue_migrated(&inet_csk(nsk)->icsk_accept_queue, req); req = nreq; @@ -1461,7 +1461,7 @@ struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child, goto child_put; } - refcount_set(&nreq->rsk_refcnt, 1); + refcount_set_release(&nreq->rsk_refcnt, 1); if (inet_csk_reqsk_queue_add(sk, nreq, child)) { __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMIGRATEREQSUCCESS); reqsk_migrate_reset(req); @@ -1514,7 +1514,7 @@ void inet_csk_listen_stop(struct sock *sk) if (nsk) { nreq = inet_reqsk_clone(req, nsk); if (nreq) { - refcount_set(&nreq->rsk_refcnt, 1); + refcount_set_release(&nreq->rsk_refcnt, 1); rcu_read_lock(); if (inet_csk_reqsk_queue_add(nsk, nreq, child)) { diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 49c70d752a892..c0accacdc3eb1 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -547,7 +547,7 @@ struct sock *__inet_lookup_established(const struct net *net, if (sk->sk_hash != hash) continue; if (likely(inet_match(net, sk, acookie, ports, dif, sdif))) { - if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) + if (unlikely(!refcount_inc_not_zero_acquire(&sk->sk_refcnt))) goto out; if (unlikely(hlist_nulls_unhashed_lockless(&sk->sk_nulls_node) || !inet_match(net, sk, acookie, ports, dif, diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c index c96d61d08854f..8997cc9db7520 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -161,7 +161,7 @@ void inet_twsk_hashdance_schedule(struct inet_timewait_sock *tw, * Also note that after this point, we lost our implicit reference * so we are not allowed to use tw anymore. */ - refcount_set(&tw->tw_refcnt, 3); + refcount_set_release(&tw->tw_refcnt, 3); inet_twsk_schedule(tw, timeo); @@ -339,7 +339,7 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo) if (check_net(sock_net(sk))) continue; - if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) + if (unlikely(!refcount_inc_not_zero_acquire(&sk->sk_refcnt))) continue; if (check_net(sock_net(sk))) { diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 8b3d4e8ee4556..d2db09bc7e29e 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -205,7 +205,7 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb, child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, NULL, &own_req, NULL); if (child) { - refcount_set(&req->rsk_refcnt, 1); + refcount_set_release(&req->rsk_refcnt, 1); sock_rps_save_rxhash(child, skb); if (rsk_drop_req(req)) { diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 444306af444ae..dbd97df1b442f 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -278,7 +278,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk, tcp_reset_xmit_timer(child, ICSK_TIME_RETRANS, req->timeout, false); - refcount_set(&req->rsk_refcnt, 2); + refcount_set_release(&req->rsk_refcnt, 2); sk_mark_napi_id_set(child, skb); diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index f4f39a20e9514..bc3a496a47dbf 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -70,7 +70,7 @@ struct sock *__inet6_lookup_established(const struct net *net, continue; if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif)) continue; - if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) + if (unlikely(!refcount_inc_not_zero_acquire(&sk->sk_refcnt))) goto out; if (unlikely(hlist_nulls_unhashed_lockless(&sk->sk_nulls_node) || -- 2.53.0