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mptcp: annotate data-races around subflow->fully_established

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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@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241021-net-next-mptcp-misc-6-13-v1-2-1ef02746504a@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Gang Yan 2024-10-21 17:14:04 +02:00 committed by Jakub Kicinski
parent a42f307664
commit 581c8cbfa9
5 changed files with 9 additions and 9 deletions
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2
net/mptcp/diag.c
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@ -47,7 +47,7 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb)
flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM; flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM;
if (sf->request_bkup) if (sf->request_bkup)
flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC; flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC;
if (sf->fully_established) if (READ_ONCE(sf->fully_established))
flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED; flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED;
if (sf->conn_finished) if (sf->conn_finished)
flags |= MPTCP_SUBFLOW_FLAG_CONNECTED; flags |= MPTCP_SUBFLOW_FLAG_CONNECTED;

4
net/mptcp/options.c
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@ -461,7 +461,7 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
return false; return false;
/* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ /* 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 || subflow->snd_isn != TCP_SKB_CB(skb)->seq ||
sk->sk_state != TCP_ESTABLISHED) sk->sk_state != TCP_ESTABLISHED)
return false; 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 /* here we can process OoO, in-window pkts, only in-sequence 4th ack
* will make the subflow fully established * 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 /* on passive sockets, check for 3rd ack retransmission
* note that msk is always set by subflow_syn_recv_sock() * note that msk is always set by subflow_syn_recv_sock()
* for mp_join subflows * for mp_join subflows

2
net/mptcp/protocol.c
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@ -3511,7 +3511,7 @@ static void schedule_3rdack_retransmission(struct sock *ssk)
struct tcp_sock *tp = tcp_sk(ssk); struct tcp_sock *tp = tcp_sk(ssk);
unsigned long timeout; unsigned long timeout;
if (mptcp_subflow_ctx(ssk)->fully_established) if (READ_ONCE(mptcp_subflow_ctx(ssk)->fully_established))
return; return;
/* reschedule with a timeout above RTT, as we must look only for drop */ /* reschedule with a timeout above RTT, as we must look only for drop */

6
net/mptcp/protocol.h
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@ -513,7 +513,6 @@ struct mptcp_subflow_context {
request_bkup : 1, request_bkup : 1,
mp_capable : 1, /* remote is MPTCP capable */ mp_capable : 1, /* remote is MPTCP capable */
mp_join : 1, /* remote is JOINing */ mp_join : 1, /* remote is JOINing */
fully_established : 1, /* path validated */
pm_notified : 1, /* PM hook called for established status */ pm_notified : 1, /* PM hook called for established status */
conn_finished : 1, conn_finished : 1,
map_valid : 1, map_valid : 1,
@ -532,10 +531,11 @@ struct mptcp_subflow_context {
is_mptfo : 1, /* subflow is doing TFO */ is_mptfo : 1, /* subflow is doing TFO */
close_event_done : 1, /* has done the post-closed part */ close_event_done : 1, /* has done the post-closed part */
mpc_drop : 1, /* the MPC option has been dropped in a rtx */ mpc_drop : 1, /* the MPC option has been dropped in a rtx */
__unused : 8; __unused : 9;
bool data_avail; bool data_avail;
bool scheduled; bool scheduled;
bool pm_listener; /* a listener managed by the kernel PM? */ bool pm_listener; /* a listener managed by the kernel PM? */
bool fully_established; /* path validated */
u32 remote_nonce; u32 remote_nonce;
u64 thmac; u64 thmac;
u32 local_nonce; 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) 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) */ /* 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 false;
return __tcp_can_send(mptcp_subflow_tcp_sock(subflow)); return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));

4
net/mptcp/subflow.c
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@ -800,7 +800,7 @@ void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
const struct mptcp_options_received *mp_opt) const struct mptcp_options_received *mp_opt)
{ {
subflow_set_remote_key(msk, subflow, 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); WRITE_ONCE(msk->fully_established, true);
if (subflow->is_mptfo) if (subflow->is_mptfo)
@ -2062,7 +2062,7 @@ static void subflow_ulp_clone(const struct request_sock *req,
} else if (subflow_req->mp_join) { } else if (subflow_req->mp_join) {
new_ctx->ssn_offset = subflow_req->ssn_offset; new_ctx->ssn_offset = subflow_req->ssn_offset;
new_ctx->mp_join = 1; 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->remote_key_valid = 1;
new_ctx->backup = subflow_req->backup; new_ctx->backup = subflow_req->backup;
new_ctx->request_bkup = subflow_req->request_bkup; new_ctx->request_bkup = subflow_req->request_bkup;