[Lguest] [PATCH 4/5] lguest: use KVM hypercalls

[Herbert Xu]

On Wed, Apr 15, 2009 at 06:23:29AM -0700, Eric W. Biederman wrote:
> 
> There is a GIGANTIC reason to have the wait queue on tfile.
> 
> If you open a file, and do ip link del tapN you can still
> be blocked waiting in poll.
> 
> The problem is specifically free_poll_entry, where we call
> remove_wait_queue and fput without calling any file methods.
> So all of this happens without struct tun_file's count being
> elevated.  Which means tun_net_uninit can detach before we get
> off of the stupid poll wait queue.

What about taking a netdev refcount before calling poll_wait?

Thanks,
-- 
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