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authorJohannes Berg <johannes@sipsolutions.net>2009-09-24 15:44:05 -0700
committerDavid S. Miller <davem@davemloft.net>2009-09-24 15:44:05 -0700
commitb8273570f802a7658827dcb077b0b517ba75a289 (patch)
tree06fcee4433089cdb16504f40b1975ebbdf69e241
parent704cc92e9ffe29458ea8831ae097c631b1160c01 (diff)
genetlink: fix netns vs. netlink table locking (2)
Similar to commit d136f1bd366fdb7e747ca7e0218171e7a00a98a5, there's a bug when unregistering a generic netlink family, which is caught by the might_sleep() added in that commit: BUG: sleeping function called from invalid context at net/netlink/af_netlink.c:183 in_atomic(): 1, irqs_disabled(): 0, pid: 1510, name: rmmod 2 locks held by rmmod/1510: #0: (genl_mutex){+.+.+.}, at: [<ffffffff8138283b>] genl_unregister_family+0x2b/0x130 #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8138270c>] __genl_unregister_mc_group+0x1c/0x120 Pid: 1510, comm: rmmod Not tainted 2.6.31-wl #444 Call Trace: [<ffffffff81044ff9>] __might_sleep+0x119/0x150 [<ffffffff81380501>] netlink_table_grab+0x21/0x100 [<ffffffff813813a3>] netlink_clear_multicast_users+0x23/0x60 [<ffffffff81382761>] __genl_unregister_mc_group+0x71/0x120 [<ffffffff81382866>] genl_unregister_family+0x56/0x130 [<ffffffffa0007d85>] nl80211_exit+0x15/0x20 [cfg80211] [<ffffffffa000005a>] cfg80211_exit+0x1a/0x40 [cfg80211] Fix in the same way by grabbing the netlink table lock before doing rcu_read_lock(). Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netlink.h1
-rw-r--r--net/netlink/af_netlink.c19
-rw-r--r--net/netlink/genetlink.c4
3 files changed, 15 insertions, 9 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 080f6ba9e73..ab5d3126831 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -187,6 +187,7 @@ extern struct sock *netlink_kernel_create(struct net *net,
extern void netlink_kernel_release(struct sock *sk);
extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
+extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
extern void netlink_clear_multicast_users(struct sock *sk, unsigned int group);
extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
extern int netlink_has_listeners(struct sock *sk, unsigned int group);
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 55180b99562..a4bafbf1509 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1609,6 +1609,16 @@ int netlink_change_ngroups(struct sock *sk, unsigned int groups)
return err;
}
+void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
+{
+ struct sock *sk;
+ struct hlist_node *node;
+ struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
+
+ sk_for_each_bound(sk, node, &tbl->mc_list)
+ netlink_update_socket_mc(nlk_sk(sk), group, 0);
+}
+
/**
* netlink_clear_multicast_users - kick off multicast listeners
*
@@ -1619,15 +1629,8 @@ int netlink_change_ngroups(struct sock *sk, unsigned int groups)
*/
void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
{
- struct sock *sk;
- struct hlist_node *node;
- struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
-
netlink_table_grab();
-
- sk_for_each_bound(sk, node, &tbl->mc_list)
- netlink_update_socket_mc(nlk_sk(sk), group, 0);
-
+ __netlink_clear_multicast_users(ksk, group);
netlink_table_ungrab();
}
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 566941e0336..44ff3f3810f 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -220,10 +220,12 @@ static void __genl_unregister_mc_group(struct genl_family *family,
struct net *net;
BUG_ON(grp->family != family);
+ netlink_table_grab();
rcu_read_lock();
for_each_net_rcu(net)
- netlink_clear_multicast_users(net->genl_sock, grp->id);
+ __netlink_clear_multicast_users(net->genl_sock, grp->id);
rcu_read_unlock();
+ netlink_table_ungrab();
clear_bit(grp->id, mc_groups);
list_del(&grp->list);