From: Paolo Abeni <pabeni@redhat.com> [ Upstream commit d39ca2590d10712f412add7a88e1dd467a7246f4 ] This reverts commit 0d4a6608f68c7532dcbfec2ea1150c9761767d03. Willem reported that after commit 0d4a6608f68c ("udp: do rmem bulk free even if the rx sk queue is empty") the memory allocated by an almost idle system with many UDP sockets can grow a lot. For stable kernel keep the solution as simple as possible and revert the offending commit. Reported-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Diagnosed-by: Eric Dumazet <eric.dumazet@gmail.com> Fixes: 0d4a6608f68c ("udp: do rmem bulk free even if the rx sk queue is empty") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/ipv4/udp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 43e72e6..02c33ff 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1302,7 +1302,8 @@ static void udp_rmem_release(struct sock *sk, int size, int partial, if (likely(partial)) { up->forward_deficit += size; size = up->forward_deficit; - if (size < (sk->sk_rcvbuf >> 2)) + if (size < (sk->sk_rcvbuf >> 2) && + !skb_queue_empty(&up->reader_queue)) return; } else { size += up->forward_deficit; -- 1.8.3