Patchwork 2.6.39-rc6-mmotm0506 - another lockdep splat (networking this time)

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Submitter Eric Dumazet
Date May 10, 2011, 3:47 a.m.
Message ID <1304999271.3050.41.camel@edumazet-laptop>
Download mbox | patch
Permalink /patch/94934/
State Accepted
Delegated to: David Miller
Headers show

Comments

Eric Dumazet - May 10, 2011, 3:47 a.m.
Le mardi 10 mai 2011 à 04:23 +0200, Eric Dumazet a écrit :

> Thanks for the report, I am taking a look how to fix this.
> 

OK here is the official patch submission

Thanks Valdis !

[PATCH net-next-2.6] net: fix two lockdep splats

Commit e67f88dd12f6 (net: dont hold rtnl mutex during netlink dump
callbacks) switched rtnl protection to RCU, but we forgot to adjust two
rcu_dereference() lockdep annotations :

inet_get_link_af_size() or inet_fill_link_af() might be called with
rcu_read_lock or rtnl held, so use rcu_dereference_rtnl()
instead of rtnl_dereference()

Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
 net/ipv4/devinet.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)



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David Miller - May 10, 2011, 3:58 a.m.
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 10 May 2011 05:47:51 +0200

> [PATCH net-next-2.6] net: fix two lockdep splats
> 
> Commit e67f88dd12f6 (net: dont hold rtnl mutex during netlink dump
> callbacks) switched rtnl protection to RCU, but we forgot to adjust two
> rcu_dereference() lockdep annotations :
> 
> inet_get_link_af_size() or inet_fill_link_af() might be called with
> rcu_read_lock or rtnl held, so use rcu_dereference_rtnl()
> instead of rtnl_dereference()
> 
> Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, thanks everyone.
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Eric Dumazet - May 10, 2011, 9:48 p.m.
Le lundi 09 mai 2011 à 20:58 -0700, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Tue, 10 May 2011 05:47:51 +0200
> 
> > [PATCH net-next-2.6] net: fix two lockdep splats
> > 
> > Commit e67f88dd12f6 (net: dont hold rtnl mutex during netlink dump
> > callbacks) switched rtnl protection to RCU, but we forgot to adjust two
> > rcu_dereference() lockdep annotations :
> > 
> > inet_get_link_af_size() or inet_fill_link_af() might be called with
> > rcu_read_lock or rtnl held, so use rcu_dereference_rtnl()
> > instead of rtnl_dereference()
> > 
> > Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> 
> Applied, thanks everyone.

David, I found you applied this patch for net-2.6, but it was
net-next-2.6 material only ...



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David Miller - May 10, 2011, 9:59 p.m.
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 10 May 2011 23:48:36 +0200

> Le lundi 09 mai 2011 à 20:58 -0700, David Miller a écrit :
>> From: Eric Dumazet <eric.dumazet@gmail.com>
>> Date: Tue, 10 May 2011 05:47:51 +0200
>> 
>> > [PATCH net-next-2.6] net: fix two lockdep splats
>> > 
>> > Commit e67f88dd12f6 (net: dont hold rtnl mutex during netlink dump
>> > callbacks) switched rtnl protection to RCU, but we forgot to adjust two
>> > rcu_dereference() lockdep annotations :
>> > 
>> > inet_get_link_af_size() or inet_fill_link_af() might be called with
>> > rcu_read_lock or rtnl held, so use rcu_dereference_rtnl()
>> > instead of rtnl_dereference()
>> > 
>> > Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
>> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
>> 
>> Applied, thanks everyone.
> 
> David, I found you applied this patch for net-2.6, but it was
> net-next-2.6 material only ...

Thanks for catching that, I'll fix this.
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Patch

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index cd9ca08..6b1eb92 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1369,7 +1369,7 @@  errout:
 
 static size_t inet_get_link_af_size(const struct net_device *dev)
 {
-	struct in_device *in_dev = __in_dev_get_rtnl(dev);
+	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
 
 	if (!in_dev)
 		return 0;
@@ -1379,7 +1379,7 @@  static size_t inet_get_link_af_size(const struct net_device *dev)
 
 static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev)
 {
-	struct in_device *in_dev = __in_dev_get_rtnl(dev);
+	struct in_device *in_dev = rcu_dereference_rtnl(dev->ip_ptr);
 	struct nlattr *nla;
 	int i;