netlink: Disable insertions/removals during rehash

[ Upstream commit: Not applicable ]

The current rhashtable rehash code is buggy and can't deal with
parallel insertions/removals without corrupting the hash table.

This patch disables it by partially reverting
c5adde9468b0714a051eac7f9666f23eb10b61f7 ("netlink: eliminate
nl_sk_hash_lock").

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index e98dc53f30ce097de700154dd9bc827979613962..0e9c28dc86b7dc204a22571516128f4138731ffe 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1052,7 +1052,7 @@ static int netlink_insert(struct sock *sk, u32 portid)
        struct netlink_table *table = &nl_table[sk->sk_protocol];
        int err;
 
-       lock_sock(sk);
+       mutex_lock(&table->hash.mutex);
 
        err = -EBUSY;
        if (nlk_sk(sk)->portid)
@@ -1074,7 +1074,7 @@ static int netlink_insert(struct sock *sk, u32 portid)
        }
 
 err:
-       release_sock(sk);
+       mutex_unlock(&table->hash.mutex);
        return err;
 }
 
@@ -1083,10 +1083,12 @@ static void netlink_remove(struct sock *sk)
        struct netlink_table *table;
 
        table = &nl_table[sk->sk_protocol];
+       mutex_lock(&table->hash.mutex);
        if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node)) {
                WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
                __sock_put(sk);
        }
+       mutex_unlock(&table->hash.mutex);
 
        netlink_table_grab();
        if (nlk_sk(sk)->subscriptions) {