Commit 9b5dc7ad authored Jul 13, 2022 by Kuniyuki Iwashima Committed by Greg Kroah-Hartman Jul 29, 2022

tcp: Fix a data-race around sysctl_tcp_probe_threshold.



[ Upstream commit 92c0aa4175474483d6cf373314343d4e624e882a ]

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

Fixes: 6b58e0a5 ("ipv4: Use binary search to choose tcp PMTU probe_size")
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>

parent 13207f94

net/ipv4/tcp_output.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2005,7 +2005,7 @@ static int tcp_mtu_probe(struct sock *sk)
		* probing process by not resetting search range to its orignal.
		*/
		if (probe_size > tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_high) \|\|
		interval < net->ipv4.sysctl_tcp_probe_threshold) {
		interval < READ_ONCE(net->ipv4.sysctl_tcp_probe_threshold)) {
		/* Check whether enough time has elaplased for
		* another round of probing.
		*/