netrom: Fix a data-race around sysctl_netrom_transport_maximum_tries

[ Upstream commit e799299aafed417cc1f32adccb2a0e5268b3f6d5 ]

We need to protect the reader reading the sysctl value because the
value can be changed concurrently.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
index 685751096744834613d800bee68c53c6fdc74980..678a7bbd84bf2e9e00a6cc11c47e706cd58624af 100644 (file)
--- a/net/netrom/af_netrom.c
+++ b/net/netrom/af_netrom.c
@@ -457,7 +457,7 @@ static int nr_create(struct net *net, struct socket *sock, int protocol,
        nr->t2     =
                msecs_to_jiffies(sysctl_netrom_transport_acknowledge_delay);
        nr->n2     =
-               msecs_to_jiffies(sysctl_netrom_transport_maximum_tries);
+               msecs_to_jiffies(READ_ONCE(sysctl_netrom_transport_maximum_tries));
        nr->t4     =
                msecs_to_jiffies(sysctl_netrom_transport_busy_delay);
        nr->idle   =