Messages in this thread | | | Date | Sun, 12 Aug 2012 11:49:29 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2] macvtap: rcu_dereference outside read-lock section |
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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 <yefremov.denis@gmail.com> > --- > 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 <mst@redhat.com>
> return i; > } > > -- > 1.7.7
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