ipv4: Fix data-races around sysctl_fib_multipath_hash_fields.

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

Fixes: ce5c9c20d364 ("ipv4: Add a sysctl to control multipath hash fields")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.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 de63a5f..85aa1c4 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -10342,7 +10342,7 @@ static void mlxsw_sp_mp4_hash_init(struct mlxsw_sp *mlxsw_sp,
                mlxsw_sp_mp_hash_inner_l3(config);
                break;
        case 3:
-               hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+               hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
                /* Outer */
                MLXSW_SP_MP_HASH_HEADER_SET(headers, IPV4_EN_NOT_TCP_NOT_UDP);
                MLXSW_SP_MP_HASH_HEADER_SET(headers, IPV4_EN_TCP_UDP);

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 521194d..4702c61 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1929,7 +1929,7 @@ static u32 fib_multipath_custom_hash_outer(const struct net *net,
                                           const struct sk_buff *skb,
                                           bool *p_has_inner)
 {
-       u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+       u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
        struct flow_keys keys, hash_keys;
 
        if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))
@@ -1958,7 +1958,7 @@ static u32 fib_multipath_custom_hash_inner(const struct net *net,
                                           const struct sk_buff *skb,
                                           bool has_inner)
 {
-       u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+       u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
        struct flow_keys keys, hash_keys;
 
        /* We assume the packet carries an encapsulation, but if none was
@@ -2018,7 +2018,7 @@ static u32 fib_multipath_custom_hash_skb(const struct net *net,
 static u32 fib_multipath_custom_hash_fl4(const struct net *net,
                                         const struct flowi4 *fl4)
 {
-       u32 hash_fields = net->ipv4.sysctl_fib_multipath_hash_fields;
+       u32 hash_fields = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_fields);
        struct flow_keys hash_keys;
 
        if (!(hash_fields & FIB_MULTIPATH_HASH_FIELD_OUTER_MASK))