From: Jesse Gross <jesse@nicira.com>
Date: Sun, 5 Dec 2010 20:03:49 +0000 (-0800)
Subject: tunneling: Add missing rcu_dereference() to cache cleaner.
X-Git-Tag: v1.1.0~676
X-Git-Url: http://git.onelab.eu/?a=commitdiff_plain;h=1e71f10f38d2ad09ee854b7e926a63744a1883e1;p=sliver-openvswitch.git

tunneling: Add missing rcu_dereference() to cache cleaner.

The cleaner for the header caching accesses the tunnel port table
without holding any locks.  However, it doesn't have a read memory
barrier, so there is no guarantee that the contents of the table
have made it to the right CPU.

Found by sparse.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
---

diff --git a/datapath/tunnel.c b/datapath/tunnel.c
index 271651bfc..aae3f3d91 100644
--- a/datapath/tunnel.c
+++ b/datapath/tunnel.c
@@ -818,7 +818,7 @@ static void cache_cleaner(struct work_struct *work)
 	schedule_cache_cleaner();
 
 	rcu_read_lock();
-	tbl_foreach(port_table, cache_cleaner_cb, NULL);
+	tbl_foreach(rcu_dereference(port_table), cache_cleaner_cb, NULL);
 	rcu_read_unlock();
 }