diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2009-07-02 23:03:55 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-07-05 18:03:18 -0700 |
| commit | d23e43658aed286b885d398ff0810f04f6aae97f (patch) | |
| tree | 49449c308390dc319fc83378dbd357041c7f27ea | |
| parent | c001c213b109c8baeeb6d012b422bf059b18368f (diff) | |
| download | linux-3.10-d23e43658aed286b885d398ff0810f04f6aae97f.tar.gz linux-3.10-d23e43658aed286b885d398ff0810f04f6aae97f.tar.bz2 linux-3.10-d23e43658aed286b885d398ff0810f04f6aae97f.zip | |
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>
| -rw-r--r-- | drivers/net/tun.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 11a0ba47b67..b393536012f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1324,20 +1324,22 @@ static int tun_chr_close(struct inode *inode, struct file *file) struct tun_file *tfile = file->private_data; struct tun_struct *tun; - - rtnl_lock(); tun = __tun_get(tfile); if (tun) { - DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name); + struct net_device *dev = tun->dev; + + DBG(KERN_INFO "%s: tun_chr_close\n", dev->name); __tun_detach(tun); /* If desireable, unregister the netdevice. */ - if (!(tun->flags & TUN_PERSIST)) - unregister_netdevice(tun->dev); - + if (!(tun->flags & TUN_PERSIST)) { + rtnl_lock(); + if (dev->reg_state == NETREG_REGISTERED) + unregister_netdevice(dev); + rtnl_unlock(); + } } - rtnl_unlock(); tun = tfile->tun; if (tun) |