Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fc566cf3 authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
Browse files

tcp_metrics: annotate data-races around tm->tcpm_vals[] 



[ Upstream commit 8c4d04f6b443869d25e59822f7cec88d647028a9 ]

tm->tcpm_vals[] values can be read or written locklessly.

Add needed READ_ONCE()/WRITE_ONCE() to document this,
and force use of tcp_metric_get() and tcp_metric_set()

Fixes: 51c5d0c4 ("tcp: Maintain dynamic metrics in local cache.")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 76b47dab

net/ipv4/tcp_metrics.c

+14 −9
Original line number Diff line number Diff line
@@ -63,17 +63,19 @@ static bool tcp_metric_locked(struct tcp_metrics_block *tm, 
	return READ_ONCE(tm->tcpm_lock) & (1 << idx);

}



static u32 tcp_metric_get(struct tcp_metrics_block *tm,

static u32 tcp_metric_get(const struct tcp_metrics_block *tm,

			  enum tcp_metric_index idx)

{

	return tm->tcpm_vals[idx];

	/* Paired with WRITE_ONCE() in tcp_metric_set() */

	return READ_ONCE(tm->tcpm_vals[idx]);

}



static void tcp_metric_set(struct tcp_metrics_block *tm,

			   enum tcp_metric_index idx,

			   u32 val)

{

	tm->tcpm_vals[idx] = val;

	/* Paired with READ_ONCE() in tcp_metric_get() */

	WRITE_ONCE(tm->tcpm_vals[idx], val);

}



static bool addr_same(const struct inetpeer_addr *a,
@@ -115,13 +117,16 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, 
	WRITE_ONCE(tm->tcpm_lock, val);



	msval = dst_metric_raw(dst, RTAX_RTT);

	tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC;

	tcp_metric_set(tm, TCP_METRIC_RTT, msval * USEC_PER_MSEC);



	msval = dst_metric_raw(dst, RTAX_RTTVAR);

	tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC;

	tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH);

	tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND);

	tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING);

	tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC);

	tcp_metric_set(tm, TCP_METRIC_SSTHRESH,

		       dst_metric_raw(dst, RTAX_SSTHRESH));

	tcp_metric_set(tm, TCP_METRIC_CWND,

		       dst_metric_raw(dst, RTAX_CWND));

	tcp_metric_set(tm, TCP_METRIC_REORDERING,

		       dst_metric_raw(dst, RTAX_REORDERING));

	if (fastopen_clear) {

		tm->tcpm_fastopen.mss = 0;

		tm->tcpm_fastopen.syn_loss = 0;
@@ -662,7 +667,7 @@ static int tcp_metrics_fill_info(struct sk_buff *msg, 
		if (!nest)

			goto nla_put_failure;

		for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) {

			u32 val = tm->tcpm_vals[i];

			u32 val = tcp_metric_get(tm, i);



			if (!val)

				continue;