netdev - [PATCH] caif: Fix race when conditionally taking rtnl lock

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Date:	Wed,  1 Jun 2011 12:55:37 +0200
From:	Sjur Brændeland <sjur.brandeland@...ricsson.com>
To:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc:	Sjur Brændeland <sjur.brandeland@...ricsson.com>
Subject: [PATCH] caif: Fix race when conditionally taking rtnl lock

Take the RTNL lock unconditionally when calling dev_close.
Taking the lock conditionally may cause race conditions.

Signed-off-by: Sjur Brændeland <sjur.brandeland@...ricsson.com>
---
 net/caif/chnl_net.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 649ebac..adbb424 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -139,17 +139,14 @@ static void close_work(struct work_struct *work)
 	struct chnl_net *dev = NULL;
 	struct list_head *list_node;
 	struct list_head *_tmp;
-	/* May be called with or without RTNL lock held */
-	int islocked = rtnl_is_locked();
-	if (!islocked)
-		rtnl_lock();
+
+	rtnl_lock();
 	list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 		dev = list_entry(list_node, struct chnl_net, list_field);
 		if (dev->state == CAIF_SHUTDOWN)
 			dev_close(dev->netdev);
 	}
-	if (!islocked)
-		rtnl_unlock();
+	rtnl_unlock();
 }
 static DECLARE_WORK(close_worker, close_work);
 
-- 
1.7.0.4

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