ipv4: convert fib_num_tclassid_users to atomic_t

commit 213f5f8f31f10aa1e83187ae20fb7fa4e626b724 upstream.

Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.

After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.

Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index cb6c125628990ae03d54f6a7516c79d33947e108..3bf9ecb6b0d3957542a5ffa48f5ba4f255edf01b 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -412,7 +412,7 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 #ifdef CONFIG_IP_ROUTE_CLASSID
 static inline int fib_num_tclassid_users(struct net *net)
 {
-       return net->ipv4.fib_num_tclassid_users;
+       return atomic_read(&net->ipv4.fib_num_tclassid_users);
 }
 #else
 static inline int fib_num_tclassid_users(struct net *net)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index c0c0791b191232b16355aa538650e4a4815b1c3a..da171544a33c704c80ad7397f3af14155a9b6fc0 100644 (file)
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -61,7 +61,7 @@ struct netns_ipv4 {
 #endif
        bool                    fib_has_custom_local_routes;
 #ifdef CONFIG_IP_ROUTE_CLASSID
-       int                     fib_num_tclassid_users;
+       atomic_t                fib_num_tclassid_users;
 #endif
        struct hlist_head       *fib_table_hash;
        bool                    fib_offload_disabled;

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index b875b98820ede0e66ac90a2f7b0b38ccbfdbbbfb..a95102fe663713e533a2e3d300679e9be9a94468 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1588,7 +1588,7 @@ static int __net_init fib_net_init(struct net *net)
        int error;
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
-       net->ipv4.fib_num_tclassid_users = 0;
+       atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
 #endif
        error = ip_fib_net_init(net);
        if (error < 0)

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b43a7ba5c6a42310546836f7bc11d2fa15234d75..08511fdf1eb762658069162841b20e0e1060e94c 100644 (file)
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -258,7 +258,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
        if (tb[FRA_FLOW]) {
                rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
                if (rule4->tclassid)
-                       net->ipv4.fib_num_tclassid_users++;
+                       atomic_inc(&net->ipv4.fib_num_tclassid_users);
        }
 #endif
 
@@ -290,7 +290,7 @@ static int fib4_rule_delete(struct fib_rule *rule)
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
        if (((struct fib4_rule *)rule)->tclassid)
-               net->ipv4.fib_num_tclassid_users--;
+               atomic_dec(&net->ipv4.fib_num_tclassid_users);
 #endif
        net->ipv4.fib_has_custom_rules = true;
 

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index dce85a9c20c60380c1436a4c57352e25835fa95c..c0b81542052376b41b95ec4d0a3b4f2f4898562a 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -222,7 +222,7 @@ void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 {
 #ifdef CONFIG_IP_ROUTE_CLASSID
        if (fib_nh->nh_tclassid)
-               net->ipv4.fib_num_tclassid_users--;
+               atomic_dec(&net->ipv4.fib_num_tclassid_users);
 #endif
        fib_nh_common_release(&fib_nh->nh_common);
 }
@@ -624,7 +624,7 @@ int fib_nh_init(struct net *net, struct fib_nh *nh,
 #ifdef CONFIG_IP_ROUTE_CLASSID
        nh->nh_tclassid = cfg->fc_flow;
        if (nh->nh_tclassid)
-               net->ipv4.fib_num_tclassid_users++;
+               atomic_inc(&net->ipv4.fib_num_tclassid_users);
 #endif
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
        nh->fib_nh_weight = nh_weight;