* [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set()
@ 2010-04-27 6:40 Eric Dumazet
2010-04-27 16:17 ` Paul E. McKenney
2010-04-27 19:55 ` David Miller
0 siblings, 2 replies; 4+ messages in thread
From: Eric Dumazet @ 2010-04-27 6:40 UTC (permalink / raw)
To: David Miller; +Cc: netdev
__sk_dst_set() might be called while no state can be integrated in a
rcu_dereference_check() condition.
So use rcu_dereference_raw() to shutup lockdep warnings (if
CONFIG_PROVE_RCU is set)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---
diff --git a/include/net/sock.h b/include/net/sock.h
index 86a8ca1..94dbdbc 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1236,8 +1236,11 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst)
struct dst_entry *old_dst;
sk_tx_queue_clear(sk);
- old_dst = rcu_dereference_check(sk->sk_dst_cache,
- lockdep_is_held(&sk->sk_dst_lock));
+ /*
+ * This can be called while sk is owned by the caller only,
+ * with no state that can be checked in a rcu_dereference_check() cond
+ */
+ old_dst = rcu_dereference_raw(sk->sk_dst_cache);
rcu_assign_pointer(sk->sk_dst_cache, dst);
dst_release(old_dst);
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set()
2010-04-27 6:40 [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set() Eric Dumazet
@ 2010-04-27 16:17 ` Paul E. McKenney
2010-04-27 19:42 ` David Miller
2010-04-27 19:55 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Paul E. McKenney @ 2010-04-27 16:17 UTC (permalink / raw)
To: Eric Dumazet; +Cc: David Miller, netdev
On Tue, Apr 27, 2010 at 08:40:43AM +0200, Eric Dumazet wrote:
> __sk_dst_set() might be called while no state can be integrated in a
> rcu_dereference_check() condition.
>
> So use rcu_dereference_raw() to shutup lockdep warnings (if
> CONFIG_PROVE_RCU is set)
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> ---
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 86a8ca1..94dbdbc 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -1236,8 +1236,11 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst)
> struct dst_entry *old_dst;
>
> sk_tx_queue_clear(sk);
> - old_dst = rcu_dereference_check(sk->sk_dst_cache,
> - lockdep_is_held(&sk->sk_dst_lock));
> + /*
> + * This can be called while sk is owned by the caller only,
> + * with no state that can be checked in a rcu_dereference_check() cond
> + */
> + old_dst = rcu_dereference_raw(sk->sk_dst_cache);
> rcu_assign_pointer(sk->sk_dst_cache, dst);
> dst_release(old_dst);
> }
>
>
> --
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set()
2010-04-27 16:17 ` Paul E. McKenney
@ 2010-04-27 19:42 ` David Miller
0 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2010-04-27 19:42 UTC (permalink / raw)
To: paulmck; +Cc: eric.dumazet, netdev
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Tue, 27 Apr 2010 09:17:16 -0700
> On Tue, Apr 27, 2010 at 08:40:43AM +0200, Eric Dumazet wrote:
>> __sk_dst_set() might be called while no state can be integrated in a
>> rcu_dereference_check() condition.
>>
>> So use rcu_dereference_raw() to shutup lockdep warnings (if
>> CONFIG_PROVE_RCU is set)
>
> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
>> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
I've applied this to net-next-2.6, thanks!
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set()
2010-04-27 6:40 [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set() Eric Dumazet
2010-04-27 16:17 ` Paul E. McKenney
@ 2010-04-27 19:55 ` David Miller
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2010-04-27 19:55 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 27 Apr 2010 08:40:43 +0200
> __sk_dst_set() might be called while no state can be integrated in a
> rcu_dereference_check() condition.
>
> So use rcu_dereference_raw() to shutup lockdep warnings (if
> CONFIG_PROVE_RCU is set)
>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Applied, thanks Eric.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2010-04-27 6:40 [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set() Eric Dumazet
2010-04-27 16:17 ` Paul E. McKenney
2010-04-27 19:42 ` David Miller
2010-04-27 19:55 ` David Miller
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