rcu: Make bugginess of code sample more evident

One of the code samples in whatisRCU.txt shows a bug, but someone scanning
the document quickly might mistake it for a valid use of RCU.  Add some
screaming comments to help keep speed-readers on track.

Reported-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 0cc7820967f4..10df0b82f459 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -265,9 +265,9 @@ rcu_dereference()
                 rcu_read_lock();
                 p = rcu_dereference(head.next);
                 rcu_read_unlock();
-                x = p->address;
+                x = p->address; /* BUG!!! */
                 rcu_read_lock();
-                y = p->data;
+                y = p->data;    /* BUG!!! */
                 rcu_read_unlock();
 
         Holding a reference from one RCU read-side critical section