From 48323978912754eb589edd2dfd4fb5f5140a2cdd Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 22 Jul 2022 11:22:01 -0700 Subject: [PATCH] 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: 6d82aa242092 ("tcp: add tcp_comp_sack_delay_ns sysctl") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_input.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 716bc95ebfb0..b86d98c07cdf 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5461,7 +5461,8 @@ send_now: 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_range_ns(&tp->compressed_ack_timer, ns_to_ktime(delay),