linux-kernel - [PATCH v2] netfilter: release skbuf when nlmsg put fail

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Message-ID: <CAL8JtxD=Vopo7fvKEnfKgOa3T=WyVH=mb_YqX9mES+n-6dJbrQ@mail.gmail.com>
Date:	Tue, 14 Oct 2014 17:42:18 +0800
From:	Houcheng Lin <houcheng@...il.com>
To:	pablo@...filter.org, Patrick McHardy <kaber@...sh.net>,
	kadlec@...ckhole.kfki.hu, davem@...emloft.net,
	netfilter-devel@...r.kernel.org, Florian Westphal <fw@...len.de>
Cc:	coreteam@...filter.org, netdev@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] netfilter: release skbuf when nlmsg put fail

When system is under heavy loading, the __nfulnl_send() may may failed
to put nlmsg into skbuf of nfulnl_instance. If not clear the skbuff on failed,
the __nfulnl_send() will still try to put next nlmsg onto this half-full skbuf
and cause the user program can never receive packet.

This patch fix this issue by releasing skbuf immediately after nlmst put
failed.

Signed-off-by: Houcheng Lin <houcheng@...il.com>
---
 net/netfilter/nfnetlink_log.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index a11c5ff..0ad5d32 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -353,15 +353,17 @@ __nfulnl_send(struct nfulnl_instance *inst)
  NLMSG_DONE,
  sizeof(struct nfgenmsg),
  0);
- if (!nlh)
+ if (!nlh) {
+ WARN_ON(1);
+ kfree_skb(inst->skb);
  goto out;
+ }
  }
  status = nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
    MSG_DONTWAIT);
-
+out:
  inst->qlen = 0;
  inst->skb = NULL;
-out:
  return status;
 }

-- 
1.7.9.5
--
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