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Commit 92c35113 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

tcp: Fix data-races around sysctl_tcp_recovery. 



[ Upstream commit e7d2ef837e14a971a05f60ea08c47f3fed1a36e4 ]

While reading sysctl_tcp_recovery, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 4f41b1c5 ("tcp: use RACK to detect losses")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 83767fe8

net/ipv4/tcp_input.c

+2 −1
Original line number Diff line number Diff line
@@ -1950,7 +1950,8 @@ static inline void tcp_init_undo(struct tcp_sock *tp) 


static bool tcp_is_rack(const struct sock *sk)

{

	return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION;

	return READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &

		TCP_RACK_LOSS_DETECTION;

}



/* If we detect SACK reneging, forget all SACK information

net/ipv4/tcp_recovery.c

+4 −2
Original line number Diff line number Diff line
@@ -33,7 +33,8 @@ static u32 tcp_rack_reo_wnd(const struct sock *sk) 
			return 0;



		if (tp->sacked_out >= tp->reordering &&

		    !(sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_NO_DUPTHRESH))

		    !(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &

		      TCP_RACK_NO_DUPTHRESH))

			return 0;

	}
@@ -204,7 +205,8 @@ void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs) 
{

	struct tcp_sock *tp = tcp_sk(sk);



	if (sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_STATIC_REO_WND ||

	if ((READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &

	     TCP_RACK_STATIC_REO_WND) ||

	    !rs->prior_delivered)

		return;