From eb4dea5853046727bfbb579f0c9a8cae7369f7c6 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 29 Dec 2008 23:04:08 -0800
Subject: net: Fix percpu counters deadlock

When we converted the protocol atomic counters such as the orphan
count and the total socket count deadlocks were introduced due to
the mismatch in BH status of the spots that used the percpu counter
operations.

Based on the diagnosis and patch by Peter Zijlstra, this patch
fixes these issues by disabling BH where we may be in process
context.

Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/tcp_ipv6.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'net/ipv6')

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 8702b06cb60..e8b8337a831 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -23,6 +23,7 @@
  *      2 of the License, or (at your option) any later version.
  */
 
+#include <linux/bottom_half.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/types.h>
@@ -1830,7 +1831,9 @@ static int tcp_v6_init_sock(struct sock *sk)
 	sk->sk_sndbuf = sysctl_tcp_wmem[1];
 	sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
+	local_bh_disable();
 	percpu_counter_inc(&tcp_sockets_allocated);
+	local_bh_enable();
 
 	return 0;
 }
-- 
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