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tcp: Fix data-races around sysctl_tcp_fastopen_blackhole_timeout.

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[ 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 <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:55 -07:00 committed by Greg Kroah-Hartman
parent 539d9ab79e
commit a77a75a0e7
1 changed files with 3 additions and 2 deletions
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5
net/ipv4/tcp_fastopen.c
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@ -495,7 +495,7 @@ 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() */
@ -516,7 +516,8 @@ 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;