From: Eric Dumazet <eric.duma...@gmail.com> Date: Thu, 15 Sep 2016 08:48:46 -0700
> From: Eric Dumazet <eduma...@google.com> > > A malicious TCP receiver, sending SACK, can force the sender to split > skbs in write queue and increase its memory usage. > > Then, when socket is closed and its write queue purged, we might > overflow sk_forward_alloc (It becomes negative) > > sk_mem_reclaim() does nothing in this case, and more than 2GB > are leaked from TCP perspective (tcp_memory_allocated is not changed) > > Then warnings trigger from inet_sock_destruct() and > sk_stream_kill_queues() seeing a not zero sk_forward_alloc > > All TCP stack can be stuck because TCP is under memory pressure. > > A simple fix is to preemptively reclaim from sk_mem_uncharge(). > > This makes sure a socket wont have more than 2 MB forward allocated, > after burst and idle period. > > Signed-off-by: Eric Dumazet <eduma...@google.com> Applied.
