On Sun, Aug 12, 2012 at 10:26:31AM +0400, Denis Efremov wrote:
> rcu_dereference occurs in update section. Replacement by
> rcu_dereference_protected in order to prevent lockdep
> complaint.
>
> Found by Linux Driver Verification project (linuxtesting.org)
>
> Signed-off-by: Denis Efremov <[email protected]>
> ---
> drivers/net/macvtap.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 0737bd4..0f0f9ce 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -94,7 +94,8 @@ static int get_slot(struct macvlan_dev *vlan, struct
> macvtap_queue *q)
> int i;
>
> for (i = 0; i < MAX_MACVTAP_QUEUES; i++) {
> - if (rcu_dereference(vlan->taps[i]) == q)
> + if (rcu_dereference_protected(vlan->taps[i],
> + lockdep_is_held(&macvtap_lock))
> == q)
And now it's too long. Maybe a temporary would be better?
struct macvtap_queue *t;
t = rcu_dereference_protected(vlan->taps[i],
lockdep_is_held(&macvtap_lock));
if (t == q)
return i;
?
Anyway -
Acked-by: Michael S. Tsirkin <[email protected]>
> return i;
> }
>
> --
> 1.7.7
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