[PATCH 5.10 048/112] tcp: Fix a data-race around sysctl_tcp_max_orphans.

Greg Kroah-Hartman
2022-07-19T12:20:31Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 47e6ab24e8c6e3ca10ceb5835413f401f90de4bf ]

While reading sysctl_tcp_max_orphans, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid a data-race.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
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>
---
net/ipv4/tcp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a3ec2a08027b..19c13ad5c121 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2490,7 +2490,8 @@ static void tcp_orphan_update(struct timer_list *unused)

static bool tcp_too_many_orphans(int shift)
{
- return READ_ONCE(tcp_orphan_cache) << shift > sysctl_tcp_max_orphans;
+ return READ_ONCE(tcp_orphan_cache) << shift >
+ READ_ONCE(sysctl_tcp_max_orphans);
}

bool tcp_check_oom(struct sock *sk, int shift)
--
2.35.1