commit 29e01227e3fcbb82443c04060fc37e7831a7774c
author Kuniyuki Iwashima <kuniyu@amazon.com> Tue Aug 23 10:47:00 2022 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Mon Sep 05 10:23:55 2022 +0200
tree d19573c7909bd6fa514b5b89dcc0766d60232329
parent add7c2af16bb55c241e114c83ed9baee62f3374b

net: Fix a data-race around sysctl_somaxconn.

[ Upstream commit 3c9ba81d72047f2e81bb535d42856517b613aba7 ]

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

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/socket.c

diff --git a/net/socket.c b/net/socket.c
index ab64ae8..6f1abcb 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1403,7 +1403,7 @@ SYSCALL_DEFINE2(listen, int, fd, int, backlog)
 
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (sock) {
-		somaxconn = sock_net(sock->sk)->core.sysctl_somaxconn;
+		somaxconn = READ_ONCE(sock_net(sock->sk)->core.sysctl_somaxconn);
 		if ((unsigned int)backlog > somaxconn)
 			backlog = somaxconn;