ipv4: Fix data-races around sysctl_fib_multipath_hash_policy.

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

Fixes: bf4e0a3db97e ("net: ipv4: add support for ECMP hash policy choice")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 868d28f..de63a5f 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -10324,7 +10324,7 @@ static void mlxsw_sp_mp4_hash_init(struct mlxsw_sp *mlxsw_sp,
        unsigned long *fields = config->fields;
        u32 hash_fields;
 
-       switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
+       switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
        case 0:
                mlxsw_sp_mp4_hash_outer_addr(config);
                break;

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 91c4f60..521194d 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2048,7 +2048,7 @@ int fib_multipath_hash(const struct net *net, const struct flowi4 *fl4,
        struct flow_keys hash_keys;
        u32 mhash = 0;
 
-       switch (net->ipv4.sysctl_fib_multipath_hash_policy) {
+       switch (READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_policy)) {
        case 0:
                memset(&hash_keys, 0, sizeof(hash_keys));
                hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;