tree 49449c308390dc319fc83378dbd357041c7f27ea
parent c001c213b109c8baeeb6d012b422bf059b18368f
author Herbert Xu <herbert@gondor.apana.org.au> 1246575835 +0000
committer David S. Miller <davem@davemloft.net> 1246842198 -0700

tun: Fix device unregister race

It is currently possible for an asynchronous device unregister
to cause the same tun device to be unregistered twice.  This
is because the unregister in tun_chr_close only checks whether
__tun_get(tfile) != NULL.  This however has nothing to do with
whether the device has already been unregistered.  All it tells
you is whether __tun_detach has been called.

This patch fixes this by using the most obvious thing to test
whether the device has been unregistered.

It also moves __tun_detach outside of rtnl_unlock since nothing
that it does requires that lock.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>