Hi Paul,

[auto build test ERROR on tip/perf/core]
[also build test ERROR on v4.11-rc5 next-20170406]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Steven-Rostedt/tracing-Add-usecase-of-synchronize_rcu_tasks-and-stack_tracer_disable/20170407-122352
config: x86_64-randconfig-x009-201714 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   kernel/rcu/tree.c: In function 'rcu_eqs_enter_common':
>> kernel/rcu/tree.c:806:2: error: implicit declaration of function 'stack_tracer_enable' [-Werror=implicit-function-declaration]
     stack_tracer_enable();
     ^~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/stack_tracer_enable +806 kernel/rcu/tree.c

   800			do_nocb_deferred_wakeup(rdp);
   801		}
   802		rcu_prepare_for_idle();
   803		stack_tracer_disable();
   804		rdtp->dynticks_nesting = 0; /* Breaks tracing momentarily. */
   805		rcu_dynticks_eqs_enter(); /* After this, tracing works again. */
 > 806		stack_tracer_enable();
   807		rcu_dynticks_task_enter();
   808	
   809		/*

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0-DAY kernel test infrastructure                Open Source Technology Center
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