>From 9c24da53c4c647a93d37d0f55a6c9ec0acef9814 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 29 Nov 2011 20:05:55 +0000
Subject: [PATCH 11/13] ipv4: fix lockdep splat in rt_cache_seq_show
[ Upstream commit 218fa90f072e4aeff9003d57e390857f4f35513e ]
After commit f2c31e32b378 (fix NULL dereferences in check_peer_redir()),
dst_get_neighbour() should be guarded by rcu_read_lock() /
rcu_read_unlock() section.
Reported-by: Miles Lane <miles.lane@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv4/route.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 32eb4a7..5218e4f 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -416,10 +416,14 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
"HHUptod\tSpecDst");
else {
struct rtable *r = v;
- // struct neighbour *n;
- int len;
+ struct neighbour *n;
+ int len, HHUptod;
+
+ rcu_read_lock();
+ n = dst_get_neighbour(&r->dst);
+ HHUptod = (n && (n->nud_state & NUD_CONNECTED)) ? 1 : 0;
+ rcu_read_unlock();
- // n = dst_get_neighbour(&r->dst);
seq_printf(seq, "%s\t%08X\t%08X\t%8X\t%d\t%u\t%d\t"
"%08X\t%d\t%u\t%u\t%02X\t%d\t%1d\t%08X%n",
r->dst.dev ? r->dst.dev->name : "*",
@@ -433,8 +437,7 @@ static int rt_cache_seq_show(struct seq_file *seq, void *v)
dst_metric(&r->dst, RTAX_RTTVAR)),
r->rt_key_tos,
r->dst.hh ? atomic_read(&r->dst.hh->hh_refcnt) : -1,
- r->dst.hh ? (r->dst.hh->hh_output ==
- dev_queue_xmit) : 0,
+ HHUptod,
r->rt_spec_dst, &len);
seq_printf(seq, "%*s\n", 127 - len, "");
--
1.7.1