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Message-Id: <20241021-net-next-mptcp-misc-6-13-v1-2-1ef02746504a@kernel.org>
Date: Mon, 21 Oct 2024 17:14:04 +0200
From: "Matthieu Baerts (NGI0)" <matttbe@...nel.org>
To: mptcp@...ts.linux.dev, Mat Martineau <martineau@...nel.org>,
Geliang Tang <geliang@...nel.org>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
"Matthieu Baerts (NGI0)" <matttbe@...nel.org>,
Gang Yan <yangang@...inos.cn>
Subject: [PATCH net-next 2/4] mptcp: annotate data-races around
subflow->fully_established
From: Gang Yan <yangang@...inos.cn>
We introduce the same handling for potential data races with the
'fully_established' flag in subflow as previously done for
msk->fully_established.
Additionally, we make a crucial change: convert the subflow's
'fully_established' from 'bit_field' to 'bool' type. This is
necessary because methods for avoiding data races don't work well
with 'bit_field'. Specifically, the 'READ_ONCE' needs to know
the size of the variable being accessed, which is not supported in
'bit_field'. Also, 'test_bit' expect the address of 'bit_field'.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/516
Signed-off-by: Gang Yan <yangang@...inos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@...nel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@...nel.org>
---
net/mptcp/diag.c | 2 +-
net/mptcp/options.c | 4 ++--
net/mptcp/protocol.c | 2 +-
net/mptcp/protocol.h | 6 +++---
net/mptcp/subflow.c | 4 ++--
5 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c
index 2d3efb405437d85c0bca70d7a92ca3a7363365e1..02205f7994d752cc505991efdf7aa0bbbfd830db 100644
--- a/net/mptcp/diag.c
+++ b/net/mptcp/diag.c
@@ -47,7 +47,7 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb)
flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM;
if (sf->request_bkup)
flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC;
- if (sf->fully_established)
+ if (READ_ONCE(sf->fully_established))
flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED;
if (sf->conn_finished)
flags |= MPTCP_SUBFLOW_FLAG_CONNECTED;
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 370c3836b7712f4ca97c99d35a20e88e85a33d70..1603b3702e2207f191fdeef2b29ea2f05fd2b910 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -461,7 +461,7 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
return false;
/* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */
- if (subflow->fully_established || snd_data_fin_enable ||
+ if (READ_ONCE(subflow->fully_established) || snd_data_fin_enable ||
subflow->snd_isn != TCP_SKB_CB(skb)->seq ||
sk->sk_state != TCP_ESTABLISHED)
return false;
@@ -930,7 +930,7 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
/* here we can process OoO, in-window pkts, only in-sequence 4th ack
* will make the subflow fully established
*/
- if (likely(subflow->fully_established)) {
+ if (likely(READ_ONCE(subflow->fully_established))) {
/* on passive sockets, check for 3rd ack retransmission
* note that msk is always set by subflow_syn_recv_sock()
* for mp_join subflows
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1f5c63eb21f0db92341ec941cfe2aec919cdd3de..a6c9661a4c45a00e982d0f68f21621c3cf33469b 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3511,7 +3511,7 @@ static void schedule_3rdack_retransmission(struct sock *ssk)
struct tcp_sock *tp = tcp_sk(ssk);
unsigned long timeout;
- if (mptcp_subflow_ctx(ssk)->fully_established)
+ if (READ_ONCE(mptcp_subflow_ctx(ssk)->fully_established))
return;
/* reschedule with a timeout above RTT, as we must look only for drop */
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 568a72702b080d7610425ce5c3a409c7b88da13a..a93e661ef5c435155066ce9cc109092661f0711c 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -513,7 +513,6 @@ struct mptcp_subflow_context {
request_bkup : 1,
mp_capable : 1, /* remote is MPTCP capable */
mp_join : 1, /* remote is JOINing */
- fully_established : 1, /* path validated */
pm_notified : 1, /* PM hook called for established status */
conn_finished : 1,
map_valid : 1,
@@ -532,10 +531,11 @@ struct mptcp_subflow_context {
is_mptfo : 1, /* subflow is doing TFO */
close_event_done : 1, /* has done the post-closed part */
mpc_drop : 1, /* the MPC option has been dropped in a rtx */
- __unused : 8;
+ __unused : 9;
bool data_avail;
bool scheduled;
bool pm_listener; /* a listener managed by the kernel PM? */
+ bool fully_established; /* path validated */
u32 remote_nonce;
u64 thmac;
u32 local_nonce;
@@ -780,7 +780,7 @@ static inline bool __tcp_can_send(const struct sock *ssk)
static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
{
/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
- if (subflow->request_join && !subflow->fully_established)
+ if (subflow->request_join && !READ_ONCE(subflow->fully_established))
return false;
return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 6170f2fff71e4f9d64837f2ebf4d81bba224fafb..860903e0642255cf9efb39da9e24c39f6547481f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -800,7 +800,7 @@ void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
const struct mptcp_options_received *mp_opt)
{
subflow_set_remote_key(msk, subflow, mp_opt);
- subflow->fully_established = 1;
+ WRITE_ONCE(subflow->fully_established, true);
WRITE_ONCE(msk->fully_established, true);
if (subflow->is_mptfo)
@@ -2062,7 +2062,7 @@ static void subflow_ulp_clone(const struct request_sock *req,
} else if (subflow_req->mp_join) {
new_ctx->ssn_offset = subflow_req->ssn_offset;
new_ctx->mp_join = 1;
- new_ctx->fully_established = 1;
+ WRITE_ONCE(new_ctx->fully_established, true);
new_ctx->remote_key_valid = 1;
new_ctx->backup = subflow_req->backup;
new_ctx->request_bkup = subflow_req->request_bkup;
--
2.45.2
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