From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- net/mptcp/fastopen.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 net/mptcp/fastopen.c (limited to 'net/mptcp/fastopen.c') diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c new file mode 100644 index 000000000..f71775090 --- /dev/null +++ b/net/mptcp/fastopen.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +/* MPTCP Fast Open Mechanism + * + * Copyright (c) 2021-2022, Dmytro SHYTYI + */ + +#include "protocol.h" + +void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow, + struct request_sock *req) +{ + struct sock *sk, *ssk; + struct sk_buff *skb; + struct tcp_sock *tp; + bool has_rxtstamp; + + /* on early fallback the subflow context is deleted by + * subflow_syn_recv_sock() + */ + if (!subflow) + return; + + ssk = subflow->tcp_sock; + sk = subflow->conn; + tp = tcp_sk(ssk); + + /* A valid TFO cookie does not guarantee SYN data. */ + skb = skb_peek(&ssk->sk_receive_queue); + if (!skb) + return; + + subflow->is_mptfo = 1; + + /* dequeue the skb from sk receive queue */ + __skb_unlink(skb, &ssk->sk_receive_queue); + skb_ext_reset(skb); + + mptcp_subflow_lend_fwdmem(subflow, skb); + + /* We copy the fastopen data, but that don't belong to the mptcp sequence + * space, need to offset it in the subflow sequence, see mptcp_subflow_get_map_offset() + */ + tp->copied_seq += skb->len; + subflow->ssn_offset += skb->len; + has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; + + /* Only the sequence delta is relevant */ + MPTCP_SKB_CB(skb)->map_seq = -skb->len; + MPTCP_SKB_CB(skb)->end_seq = 0; + MPTCP_SKB_CB(skb)->offset = 0; + MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; + MPTCP_SKB_CB(skb)->cant_coalesce = 1; + + mptcp_data_lock(sk); + DEBUG_NET_WARN_ON_ONCE(sock_owned_by_user_nocheck(sk)); + + mptcp_borrow_fwdmem(sk, skb); + skb_set_owner_r(skb, sk); + __skb_queue_tail(&sk->sk_receive_queue, skb); + mptcp_sk(sk)->bytes_received += skb->len; + + sk->sk_data_ready(sk); + + mptcp_data_unlock(sk); +} -- cgit v1.3.1