On Tue, Mar 11, 2014 at 1:45 AM, Eric W. Biederman
[off-list ref] wrote:

-       work = napi->poll(napi, budget);
-       trace_napi_poll(napi);
+       /* Use a budget of 0 to request the drivers not process
+        * their receive queue.  Warn when they do anyway.
+        */
+       work = napi->poll(napi, 0);
+       WARN_ON_ONCE(work != 0);

Adding more printk's in netpoll call path would only bring more troubles.