net: Convert atomic_t net::count to refcount_t
Since net could be obtained from RCU lists,
and there is a race with net destruction,
the patch converts net::count to refcount_t.
This provides sanity checks for the cases of
incrementing counter of already dead net,
when maybe_get_net() has to used instead
of get_net().
Drivers: allyesconfig and allmodconfig are OK.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 60a71be..2213d45 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -35,7 +35,7 @@ LIST_HEAD(net_namespace_list);
EXPORT_SYMBOL_GPL(net_namespace_list);
struct net init_net = {
- .count = ATOMIC_INIT(1),
+ .count = REFCOUNT_INIT(1),
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
};
EXPORT_SYMBOL(init_net);
@@ -224,10 +224,10 @@ int peernet2id_alloc(struct net *net, struct net *peer)
bool alloc;
int id;
- if (atomic_read(&net->count) == 0)
+ if (refcount_read(&net->count) == 0)
return NETNSA_NSID_NOT_ASSIGNED;
spin_lock_bh(&net->nsid_lock);
- alloc = atomic_read(&peer->count) == 0 ? false : true;
+ alloc = refcount_read(&peer->count) == 0 ? false : true;
id = __peernet2id_alloc(net, peer, &alloc);
spin_unlock_bh(&net->nsid_lock);
if (alloc && id >= 0)
@@ -284,7 +284,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
int error = 0;
LIST_HEAD(net_exit_list);
- atomic_set(&net->count, 1);
+ refcount_set(&net->count, 1);
refcount_set(&net->passive, 1);
net->dev_base_seq = 1;
net->user_ns = user_ns;
