netrom: Fix a data-race around sysctl_netrom_default_path_quality

[ Upstream commit 958d6145a6d9ba9e075c921aead8753fb91c9101 ]

We need to protect the reader reading sysctl_netrom_default_path_quality
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/nr_route.c b/net/netrom/nr_route.c
index baea3cbd76ca5bb5803974a75c3f10f87cc80140..6f709fdffc11fad0a9245cd1cab523378ea48219 100644 (file)
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -153,7 +153,7 @@ static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
                nr_neigh->digipeat = NULL;
                nr_neigh->ax25     = NULL;
                nr_neigh->dev      = dev;
-               nr_neigh->quality  = sysctl_netrom_default_path_quality;
+               nr_neigh->quality  = READ_ONCE(sysctl_netrom_default_path_quality);
                nr_neigh->locked   = 0;
                nr_neigh->count    = 0;
                nr_neigh->number   = nr_neigh_no++;