Commit a89778d8ba ("tipc: add support
for link state subscriptions") introduced below possible deadlock
scenario:
CPU0 CPU1
T0: tipc_publish() link_timeout()
T1: tipc_nametbl_publish() [grab node lock]*
T2: [grab nametbl write lock]* link_state_event()
T3: named_cluster_distribute() link_activate()
T4: [grab node lock]* tipc_node_link_up()
T5: tipc_nametbl_publish()
T6: [grab nametble write lock]*
The opposite order of holding nametbl write lock and node lock on
above two different paths may result in a deadlock. If we move the
the delivery of named messages via link out of name nametbl lock,
the reverse order of holding locks will be eliminated, as a result,
the deadlock will be killed as well.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
eab8c04573