From 4cc070e0ef2d212780028b62d8eb286c098c3e9c Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 22 Jul 2022 11:22:03 -0700 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_comp_sack_nr. [ Upstream commit 79f55473bfc8ac51bd6572929a679eeb4da22251 ] While reading sysctl_tcp_comp_sack_nr, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 9c21d2fc41c0 ("tcp: add tcp_comp_sack_nr sysctl") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 7b59386..a33e6aa 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5491,7 +5491,7 @@ send_now: } if (!tcp_is_sack(tp) || - tp->compressed_ack >= sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr) + tp->compressed_ack >= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_nr)) goto send_now; if (tp->compressed_ack_rcv_nxt != tp->rcv_nxt) { -- 2.7.4