From: Kuniyuki Iwashima Date: Fri, 15 Jul 2022 17:17:55 +0000 (-0700) Subject: tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout. X-Git-Tag: v5.10.134~48 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0dc2f19d8c2636cebda7976b5ea40c6d69f0d891;p=thirdparty%2Fkernel%2Fstable.git tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout. [ Upstream commit 021266ec640c7a4527e6cd4b7349a512b351de1d ] 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 Signed-off-by: Sasha Levin --- diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index ed7aa6ae7b51b..39fb037ce5f3f 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -506,7 +506,7 @@ 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() */ @@ -527,7 +527,8 @@ 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;