[PATCH 5.15 25/76] netrom: Fix a data-race around sysctl_netrom_routing_control

[Sasha Levin]

From: Jason Xing <kernelxing@xxxxxxxxxxx>

[ Upstream commit b5dffcb8f71bdd02a4e5799985b51b12f4eeaf76 ]

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@xxxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/netrom/nr_route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index e5d24462d5100..56bec5b5b37c7 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -780,7 +780,7 @@ int nr_route_frame(struct sk_buff *skb, ax25_cb *ax25)
 		return ret;
 	}
 
-	if (!sysctl_netrom_routing_control && ax25 != NULL)
+	if (!READ_ONCE(sysctl_netrom_routing_control) && ax25 != NULL)
 		return 0;
 
 	/* Its Time-To-Live has expired */
-- 
2.43.0