From 78dfb789b69f161703ef322a0c2e3e61c7f7573a Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 27 Mar 2014 12:54:32 +0800 Subject: [PATCH] tipc: acquire necessary locks in named_cluster_distribute routine The 'tipc_node_list' is guarded by tipc_net_lock and 'links' array defined in 'tipc_node' structure is protected by node lock as well. Without acquiring the two locks in named_cluster_distribute() a fatal oops may happen in case that a destroyed link might be got and then accessed. Therefore, above mentioned two locks must be held in named_cluster_distribute() to prevent the issue from happening accidentally. As 'links' array in node struct must be protected by node lock, we have to move the code of selecting an active link from tipc_link_xmit() to named_cluster_distribute() and then call __tipc_link_xmit() with the selected link to deliver name messages. Signed-off-by: Ying Xue Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/name_distr.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c index 893c49a3d98a..c5904d196cd3 100644 --- a/net/tipc/name_distr.c +++ b/net/tipc/name_distr.c @@ -131,16 +131,24 @@ static void named_cluster_distribute(struct sk_buff *buf) { struct sk_buff *buf_copy; struct tipc_node *n_ptr; + struct tipc_link *l_ptr; + read_lock_bh(&tipc_net_lock); list_for_each_entry(n_ptr, &tipc_node_list, list) { - if (tipc_node_active_links(n_ptr)) { + spin_lock_bh(&n_ptr->lock); + l_ptr = n_ptr->active_links[n_ptr->addr & 1]; + if (l_ptr) { buf_copy = skb_copy(buf, GFP_ATOMIC); - if (!buf_copy) + if (!buf_copy) { + spin_unlock_bh(&n_ptr->lock); break; + } msg_set_destnode(buf_msg(buf_copy), n_ptr->addr); - tipc_link_xmit(buf_copy, n_ptr->addr, n_ptr->addr); + __tipc_link_xmit(l_ptr, buf_copy); } + spin_unlock_bh(&n_ptr->lock); } + read_unlock_bh(&tipc_net_lock); kfree_skb(buf); } -- 2.30.2