Piteball/android_kernel_google_msm
1
0
Fork 0
mirror of https://github.com/followmsi/android_kernel_google_msm.git synced 2024-09-22 12:42:50 +00:00
Code Issues Projects Releases Wiki Activity

tun: Fix device unregister race

Browse source 
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>
This commit is contained in:
Herbert Xu 2009-07-02 23:03:55 +00:00 committed by David S. Miller
parent c001c213b1
commit d23e43658a
1 changed files with 9 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
drivers/net/tun.c
View file

@ -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)