Commit 69e0b33a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: annotate data-races around tw->tw_ts_recent and tw->tw_ts_recent_stamp 



These fields can be read and written locklessly, add annotations
around these minor races.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b907194a

net/ipv4/tcp_ipv4.c

+7 −5
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 
	const struct inet_timewait_sock *tw = inet_twsk(sktw);

	const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);

	struct tcp_sock *tp = tcp_sk(sk);

	int ts_recent_stamp;



	if (reuse == 2) {

		/* Still does not detect *everything* that goes through
@@ -152,9 +153,10 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 
	   If TW bucket has been already destroyed we fall back to VJ's scheme

	   and use initial timestamp retrieved from peer table.

	 */

	if (tcptw->tw_ts_recent_stamp &&

	ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);

	if (ts_recent_stamp &&

	    (!twp || (reuse && time_after32(ktime_get_seconds(),

					    tcptw->tw_ts_recent_stamp)))) {

					    ts_recent_stamp)))) {

		/* inet_twsk_hashdance() sets sk_refcnt after putting twsk

		 * and releasing the bucket lock.

		 */
@@ -178,8 +180,8 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) 
			if (!seq)

				seq = 1;

			WRITE_ONCE(tp->write_seq, seq);

			tp->rx_opt.ts_recent	   = tcptw->tw_ts_recent;

			tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;

			tp->rx_opt.ts_recent	   = READ_ONCE(tcptw->tw_ts_recent);

			tp->rx_opt.ts_recent_stamp = ts_recent_stamp;

		}



		return 1;
@@ -1064,7 +1066,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) 
			tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,

			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,

			tcp_tw_tsval(tcptw),

			tcptw->tw_ts_recent,

			READ_ONCE(tcptw->tw_ts_recent),

			tw->tw_bound_dev_if, &key,

			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,

			tw->tw_tos,

net/ipv4/tcp_minisocks.c

+14 −8
Original line number Diff line number Diff line
@@ -101,16 +101,18 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
	struct tcp_options_received tmp_opt;

	struct tcp_timewait_sock *tcptw = tcp_twsk((struct sock *)tw);

	bool paws_reject = false;

	int ts_recent_stamp;



	tmp_opt.saw_tstamp = 0;

	if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {

	ts_recent_stamp = READ_ONCE(tcptw->tw_ts_recent_stamp);

	if (th->doff > (sizeof(*th) >> 2) && ts_recent_stamp) {

		tcp_parse_options(twsk_net(tw), skb, &tmp_opt, 0, NULL);



		if (tmp_opt.saw_tstamp) {

			if (tmp_opt.rcv_tsecr)

				tmp_opt.rcv_tsecr -= tcptw->tw_ts_offset;

			tmp_opt.ts_recent	= tcptw->tw_ts_recent;

			tmp_opt.ts_recent_stamp	= tcptw->tw_ts_recent_stamp;

			tmp_opt.ts_recent	= READ_ONCE(tcptw->tw_ts_recent);

			tmp_opt.ts_recent_stamp	= ts_recent_stamp;

			paws_reject = tcp_paws_reject(&tmp_opt, th->rst);

		}

	}
@@ -152,8 +154,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
		twsk_rcv_nxt_update(tcptw, TCP_SKB_CB(skb)->end_seq);



		if (tmp_opt.saw_tstamp) {

			tcptw->tw_ts_recent_stamp = ktime_get_seconds();

			tcptw->tw_ts_recent	  = tmp_opt.rcv_tsval;

			WRITE_ONCE(tcptw->tw_ts_recent_stamp,

				  ktime_get_seconds());

			WRITE_ONCE(tcptw->tw_ts_recent,

				   tmp_opt.rcv_tsval);

		}



		inet_twsk_reschedule(tw, TCP_TIMEWAIT_LEN);
@@ -197,8 +201,10 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
		}



		if (tmp_opt.saw_tstamp) {

			tcptw->tw_ts_recent	  = tmp_opt.rcv_tsval;

			tcptw->tw_ts_recent_stamp = ktime_get_seconds();

			WRITE_ONCE(tcptw->tw_ts_recent,

				   tmp_opt.rcv_tsval);

			WRITE_ONCE(tcptw->tw_ts_recent_stamp,

				   ktime_get_seconds());

		}



		inet_twsk_put(tw);
@@ -225,7 +231,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
	if (th->syn && !th->rst && !th->ack && !paws_reject &&

	    (after(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt) ||

	     (tmp_opt.saw_tstamp &&

	      (s32)(tcptw->tw_ts_recent - tmp_opt.rcv_tsval) < 0))) {

	      (s32)(READ_ONCE(tcptw->tw_ts_recent) - tmp_opt.rcv_tsval) < 0))) {

		u32 isn = tcptw->tw_snd_nxt + 65535 + 2;

		if (isn == 0)

			isn++;

net/ipv6/tcp_ipv6.c

+3 −3
Original line number Diff line number Diff line
@@ -1196,9 +1196,9 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) 
	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,

			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,

			tcp_tw_tsval(tcptw),

			tcptw->tw_ts_recent, tw->tw_bound_dev_if, &key,

			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,

			tw->tw_txhash);

			READ_ONCE(tcptw->tw_ts_recent), tw->tw_bound_dev_if,

			&key, tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel),

			tw->tw_priority, tw->tw_txhash);



#ifdef CONFIG_TCP_AO

out: