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tcp: Fix data-races around sysctl_tcp_recovery.

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[ Upstream commit e7d2ef837e14a971a05f60ea08c47f3fed1a36e4 ]

While reading sysctl_tcp_recovery, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 4f41b1c58a32 ("tcp: use RACK to detect losses")
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 2022-07-18 10:26:46 -07:00 committed by Greg Kroah-Hartman
parent 5037ca9e4b
commit a31e2d0cb5
2 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/ipv4/tcp_input.c
View File

@ -2087,7 +2087,8 @@ static inline void tcp_init_undo(struct tcp_sock *tp)
static bool tcp_is_rack(const struct sock *sk)
{
return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION;
return READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &
TCP_RACK_LOSS_DETECTION;
}
/* If we detect SACK reneging, forget all SACK information

6
net/ipv4/tcp_recovery.c
View File

@ -19,7 +19,8 @@ static u32 tcp_rack_reo_wnd(const struct sock *sk)
return 0;
if (tp->sacked_out >= tp->reordering &&
!(sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_NO_DUPTHRESH))
!(READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &
TCP_RACK_NO_DUPTHRESH))
return 0;
}
@ -192,7 +193,8 @@ void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs)
{
struct tcp_sock *tp = tcp_sk(sk);
if (sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_STATIC_REO_WND ||
if ((READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_recovery) &
TCP_RACK_STATIC_REO_WND) ||
!rs->prior_delivered)
return;