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* [PATCH] macvtap: rcu_dereference outside read-lock section
@ 2012-08-11 10:05 Denis Efremov
  2012-08-12  1:16 ` David Miller
  0 siblings, 1 reply; 5+ messages in thread
From: Denis Efremov @ 2012-08-11 10:05 UTC (permalink / raw)
  To: David S. Miller
  Cc: Denis Efremov, Michael S. Tsirkin, Jason Wang, Eric W. Biederman,
	Ian Campbell, netdev, linux-kernel, ldv-project

In this case it is not an error. rcu_dereference
occurs in update section. Replacement by
rcu_dereference_protected (with spinlock) 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..8ef11a8 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;
 	}
 
-- 
1.7.7

^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2012-08-12 20:41 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-08-11 10:05 [PATCH] macvtap: rcu_dereference outside read-lock section Denis Efremov
2012-08-12  1:16 ` David Miller
2012-08-12  6:26   ` [PATCH v2] " Denis Efremov
2012-08-12  8:49     ` Michael S. Tsirkin
2012-08-12 20:41       ` David Miller

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