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: cf1ef3f071 ("net/tcp_fastopen: Disable active side TFO in certain scenarios")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:55 -07:00 committed by David S. Miller
parent 5a54213318
commit 021266ec64

View File

@ -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;