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Commit d42f68a9 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
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tcp: Fix a data-race around sysctl_tcp_comp_sack_delay_ns. 



[ Upstream commit 4866b2b0f7672b6d760c4b8ece6fb56f965dcc8a ]

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

Fixes: 6d82aa24 ("tcp: add tcp_comp_sack_delay_ns sysctl")
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 c2b57a4d

net/ipv4/tcp_input.c

+2 −1
Original line number Diff line number Diff line
@@ -5326,7 +5326,8 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) 
	if (tp->srtt_us && tp->srtt_us < rtt)

		rtt = tp->srtt_us;



	delay = min_t(unsigned long, sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns,

	delay = min_t(unsigned long,

		      READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_delay_ns),

		      rtt * (NSEC_PER_USEC >> 3)/20);

	sock_hold(sk);

	hrtimer_start(&tp->compressed_ack_timer, ns_to_ktime(delay),