diff options
| -rw-r--r-- | include/linux/genetlink.h | 4 | ||||
| -rw-r--r-- | include/net/genetlink.h | 5 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 24 | ||||
| -rw-r--r-- | net/netlink/af_netlink.h | 1 | ||||
| -rw-r--r-- | net/netlink/genetlink.c | 16 |
5 files changed, 35 insertions, 15 deletions
diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h index 55b6857..09460d6 100644 --- a/include/linux/genetlink.h +++ b/include/linux/genetlink.h @@ -11,6 +11,10 @@ extern void genl_unlock(void); extern int lockdep_genl_is_held(void); #endif +/* for synchronisation between af_netlink and genetlink */ +extern atomic_t genl_sk_destructing_cnt; +extern wait_queue_head_t genl_sk_destructing_waitq; + /** * rcu_dereference_genl - rcu_dereference with debug checking * @p: The pointer to read, prior to dereferencing diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 2ea2c55..6c92415 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -35,7 +35,10 @@ struct genl_info; * undo operations done by pre_doit, for example release locks * @mcast_bind: a socket bound to the given multicast group (which * is given as the offset into the groups array) - * @mcast_unbind: a socket was unbound from the given multicast group + * @mcast_unbind: a socket was unbound from the given multicast group. + * Note that unbind() will not be called symmetrically if the + * generic netlink family is removed while there are still open + * sockets. * @attrbuf: buffer to store parsed attributes * @family_list: family list * @mcgrps: multicast groups used by this family (private) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 84ea76c..02fdde2 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -61,6 +61,7 @@ #include <linux/rhashtable.h> #include <asm/cacheflush.h> #include <linux/hash.h> +#include <linux/genetlink.h> #include <net/net_namespace.h> #include <net/sock.h> @@ -1095,6 +1096,8 @@ static void netlink_remove(struct sock *sk) __sk_del_bind_node(sk); netlink_update_listeners(sk); } + if (sk->sk_protocol == NETLINK_GENERIC) + atomic_inc(&genl_sk_destructing_cnt); netlink_table_ungrab(); } @@ -1211,6 +1214,20 @@ static int netlink_release(struct socket *sock) * will be purged. */ + /* must not acquire netlink_table_lock in any way again before unbind + * and notifying genetlink is done as otherwise it might deadlock + */ + if (nlk->netlink_unbind) { + int i; + + for (i = 0; i < nlk->ngroups; i++) + if (test_bit(i, nlk->groups)) + nlk->netlink_unbind(sock_net(sk), i + 1); + } + if (sk->sk_protocol == NETLINK_GENERIC && + atomic_dec_return(&genl_sk_destructing_cnt) == 0) + wake_up(&genl_sk_destructing_waitq); + sock->sk = NULL; wake_up_interruptible_all(&nlk->wait); @@ -1246,13 +1263,6 @@ static int netlink_release(struct socket *sock) netlink_table_ungrab(); } - if (nlk->netlink_unbind) { - int i; - - for (i = 0; i < nlk->ngroups; i++) - if (test_bit(i, nlk->groups)) - nlk->netlink_unbind(sock_net(sk), i + 1); - } kfree(nlk->groups); nlk->groups = NULL; diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index f123a88..f1c31b3 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -2,6 +2,7 @@ #define _AF_NETLINK_H #include <linux/rhashtable.h> +#include <linux/atomic.h> #include <net/sock.h> #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index c18d3f5..ee57459 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -23,6 +23,9 @@ static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */ static DECLARE_RWSEM(cb_lock); +atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0); +DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq); + void genl_lock(void) { mutex_lock(&genl_mutex); @@ -435,15 +438,18 @@ int genl_unregister_family(struct genl_family *family) genl_lock_all(); - genl_unregister_mc_groups(family); - list_for_each_entry(rc, genl_family_chain(family->id), family_list) { if (family->id != rc->id || strcmp(rc->name, family->name)) continue; + genl_unregister_mc_groups(family); + list_del(&rc->family_list); family->n_ops = 0; - genl_unlock_all(); + up_write(&cb_lock); + wait_event(genl_sk_destructing_waitq, + atomic_read(&genl_sk_destructing_cnt) == 0); + genl_unlock(); kfree(family->attrbuf); genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); @@ -1014,7 +1020,6 @@ static int genl_bind(struct net *net, int group) static void genl_unbind(struct net *net, int group) { int i; - bool found = false; down_read(&cb_lock); for (i = 0; i < GENL_FAM_TAB_SIZE; i++) { @@ -1027,14 +1032,11 @@ static void genl_unbind(struct net *net, int group) if (f->mcast_unbind) f->mcast_unbind(net, fam_grp); - found = true; break; } } } up_read(&cb_lock); - - WARN_ON(!found); } static int __net_init genl_pernet_init(struct net *net) |