xen-netfront: fix potential deadlock in xennet_remove()
[ Upstream commit c2c63310 ] There's a potential race in xennet_remove(); this is what the driver is doing upon unregistering a network device: 1. state = read bus state 2. if state is not "Closed": 3. request to set state to "Closing" 4. wait for state to be set to "Closing" 5. request to set state to "Closed" 6. wait for state to be set to "Closed" If the state changes to "Closed" immediately after step 1 we are stuck forever in step 4, because the state will never go back from "Closed" to "Closing". Make sure to check also for state == "Closed" in step 4 to prevent the deadlock. Also add a 5 sec timeout any time we wait for the bus state to change, to avoid getting stuck forever in wait_event(). Signed-off-by:Andrea Righi <andrea.righi@canonical.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Sasha Levin <sashal@kernel.org>
parent
a7b488d6
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