From 021266ec640c7a4527e6cd4b7349a512b351de1d Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 15 Jul 2022 10:17:55 -0700 Subject: tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout. While reading sysctl_tcp_fastopen_blackhole_timeout, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: cf1ef3f0719b ("net/tcp_fastopen: Disable active side TFO in certain scenarios") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller --- net/ipv4/tcp_fastopen.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 0acdb5473850..825b216d11f5 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -489,7 +489,7 @@ void tcp_fastopen_active_disable(struct sock *sk) { struct net *net = sock_net(sk); - if (!sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout) + if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout)) return; /* Paired with READ_ONCE() in tcp_fastopen_active_should_disable() */ @@ -510,7 +510,8 @@ void tcp_fastopen_active_disable(struct sock *sk) */ bool tcp_fastopen_active_should_disable(struct sock *sk) { - unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout; + unsigned int tfo_bh_timeout = + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout); unsigned long timeout; int tfo_da_times; int multiplier; -- cgit v1.2.3