ipv4: Fix data-races around sysctl_fib_multipath_hash_policy.

[ Upstream commit 7998c12 ] While reading sysctl_fib_multipath_hash_policy, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: bf4e0a3 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
xanmod · Jul 29, 2022 · 21fb844 · 21fb844
1 parent b8d345d
commit 21fb844
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -9588,7 +9588,7 @@ 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
@@ -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;