Re: [PATCH] __free_pages_ok oops

[David S. Miller]

   From: Andrew Morton <[e-mail]>
   Date: Wed, 06 Feb 2002 22:19:32 -0800
   
   It's only a problem if this is the final put_page().  In the
   case of sendfile(), process-context code can be taught to take
   a temporary reference on the page, and only release it after the network
   stack is known to have finished with the page. sendfile is synchronous, yes?

Userspace can return long before the SKBs are free'd up.  That SKB
free doesn't happen until the ACKs come back from the receiver.