From: Denis Efremov <yefremov.denis@gmail.com>
Date: Sat, 11 Aug 2012 20:26:31 +0000 (+0000)
Subject: macvtap: rcu_dereference outside read-lock section
X-Git-Tag: v3.6-rc2~15^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3a7f8c34fefb109903af9a0fac6d0d05f93335c5;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git

macvtap: rcu_dereference outside read-lock section

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>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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)
 			return i;
 	}