From: Xiaotian Feng on
From b0240dd1e2ee0b4dc30f98c67cfe35e8c1833753 Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <dfeng(a)>
Date: Tue, 13 Jul 2010 11:36:53 +0800
Subject: [PATCH 18/30] netvm: filter emergency skbs.

Toss all emergency packets not for a SOCK_MEMALLOC socket. This ensures our
precious memory reserve doesn't get stuck waiting for user-space.

The correctness of this approach relies on the fact that networks must be
assumed lossy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)>
Signed-off-by: Suresh Jayaraman <sjayaraman(a)>
Signed-off-by: Xiaotian Feng <dfeng(a)>
net/core/filter.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 52b051f..bdcbc14 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -82,6 +82,9 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
int err;
struct sk_filter *filter;

+ if (skb_emergency(skb) && !sk_has_memalloc(sk))
+ return -ENOMEM;
err = security_sock_rcv_skb(sk, skb);
if (err)
return err;

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