Commit 021266ec authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

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: cf1ef3f0 ("net/tcp_fastopen: Disable active side TFO in certain scenarios")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5a542133

net/ipv4/tcp_fastopen.c

+3 −2
Original line number Diff line number Diff line
@@ -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;