Commits
Sowmini Varadhan committed 2a968dd8f7d
sunvnet: Use RCU to synchronize port usage with vnet_port_remove()
A vnet_port_remove could be triggered as a result of an ldm-unbind
operation by the peer, module unload, or other changes to the
inter-vnet-link configuration. When this is concurrent with
vnet_start_xmit(), there are several race sequences possible,
such as
thread 1 thread 2
vnet_start_xmit
-> tx_port_find
spin_lock_irqsave(&vp->lock..)
ret = __tx_port_find(..)
spin_lock_irqrestore(&vp->lock..)
vio_remove -> ..
->vnet_port_remove
spin_lock_irqsave(&vp->lock..)
cleanup
spin_lock_irqrestore(&vp->lock..)
kfree(port)
/* attempt to use ret will bomb */
This patch adds RCU locking for port access so that vnet_port_remove
will correctly clean up port-related state.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>