From: Kuniyuki Iwashima Date: Wed, 13 Jul 2022 20:52:04 +0000 (-0700) Subject: tcp: Fix a data-race around sysctl_tcp_probe_threshold. X-Git-Tag: v4.9.325~16 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9b5dc7ad6da1373d3c60d4b869d688f996e5d219;p=thirdparty%2Fkernel%2Fstable.git 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: 6b58e0a5f32d ("ipv4: Use binary search to choose tcp PMTU probe_size") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index e0009cd69da75..5b6d935a028c2 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -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. */