Commit 1330ffac authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

tcp: Fix a data-race around sysctl_tcp_min_rtt_wlen. 



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

Fixes: f6722583 ("tcp: track min RTT using windowed min-filter")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2455e61b

net/ipv4/tcp_input.c

+1 −1
Original line number Diff line number Diff line
@@ -3058,7 +3058,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, 


static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag)

{

	u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ;

	u32 wlen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen) * HZ;

	struct tcp_sock *tp = tcp_sk(sk);



	if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) {