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authorYing Xue <ying.xue@windriver.com>2015-03-18 04:32:57 +0300
committerDavid S. Miller <davem@davemloft.net>2015-03-18 05:11:26 +0300
commit76100a8a64bc2ae898bc49d51dd28c1f4f5ed37b (patch)
treec868f57ef59ff263a8ed7d4ec17bf7620bb8554a /net/tipc/socket.h
parent5284143057708af297eea10812a67d18e42e9abe (diff)
downloadlinux-76100a8a64bc2ae898bc49d51dd28c1f4f5ed37b.tar.xz
tipc: fix netns refcnt leak
When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reported-by: Cong Wang <cwang@twopensource.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/socket.h')
-rw-r--r--net/tipc/socket.h4
1 files changed, 0 insertions, 4 deletions
diff --git a/net/tipc/socket.h b/net/tipc/socket.h
index 238f1b7bd9bd..bf6551389522 100644
--- a/net/tipc/socket.h
+++ b/net/tipc/socket.h
@@ -44,10 +44,6 @@
SKB_TRUESIZE(TIPC_MAX_USER_MSG_SIZE))
int tipc_socket_init(void);
void tipc_socket_stop(void);
-int tipc_sock_create_local(struct net *net, int type, struct socket **res);
-void tipc_sock_release_local(struct socket *sock);
-int tipc_sock_accept_local(struct socket *sock, struct socket **newsock,
- int flags);
int tipc_sk_rcv(struct net *net, struct sk_buff_head *inputq);
void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq,
struct sk_buff_head *inputq);