From 220b1647ec8d863a4680f19e246926dab50c2313 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 7 Sep 2022 09:24:36 +0000 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_comp_sack_nr. stable inclusion from stable-v4.19.255 commit 37ef2ea54885ffebc45fae73f04352bab0ffb367 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ CVE: NA -------------------------------- [ 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 Signed-off-by: Yongqiang Liu --- 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 01278fdd981f..921e09c7d716 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5274,7 +5274,7 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) } 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) { -- GitLab