[linux-next:master 10814/11322] arch/parisc/kernel/ftrace.c:27:32: error: 'ftrace_graph_enable' defined but not used

[kernel test robot <lkp@xxxxxxxxx>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   9ae1fbdeabd3b3f668ad0bcb47d64b3a9fb4f8fc
commit: 60017239b6b2892665070c812fee1b6a1c8137dc [10814/11322] parisc/ftrace: use static key to enable/disable function graph tracer
config: parisc-buildonly-randconfig-r004-20211025 (attached as .config)
compiler: hppa-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=60017239b6b2892665070c812fee1b6a1c8137dc
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 60017239b6b2892665070c812fee1b6a1c8137dc
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=parisc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   arch/parisc/kernel/ftrace.c:55:20: error: no previous prototype for 'ftrace_function_trampoline' [-Werror=missing-prototypes]
      55 | void notrace __hot ftrace_function_trampoline(unsigned long parent,
         |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/static_key.h:1,
                    from include/linux/context_tracking_state.h:6,
                    from include/linux/hardirq.h:5,
                    from include/linux/interrupt.h:11,
                    from include/linux/trace_recursion.h:5,
                    from include/linux/ftrace.h:10,
                    from arch/parisc/kernel/ftrace.c:14:
>> arch/parisc/kernel/ftrace.c:27:32: error: 'ftrace_graph_enable' defined but not used [-Werror=unused-variable]
      27 | static DEFINE_STATIC_KEY_FALSE(ftrace_graph_enable);
         |                                ^~~~~~~~~~~~~~~~~~~
   include/linux/jump_label.h:379:33: note: in definition of macro 'DEFINE_STATIC_KEY_FALSE'
     379 |         struct static_key_false name = STATIC_KEY_FALSE_INIT
         |                                 ^~~~
   cc1: all warnings being treated as errors


vim +/ftrace_graph_enable +27 arch/parisc/kernel/ftrace.c

  > 14	#include <linux/ftrace.h>
    15	#include <linux/uaccess.h>
    16	#include <linux/kprobes.h>
    17	#include <linux/ptrace.h>
    18	#include <linux/jump_label.h>
    19	
    20	#include <asm/assembly.h>
    21	#include <asm/sections.h>
    22	#include <asm/ftrace.h>
    23	#include <asm/patch.h>
    24	
    25	#define __hot __section(".text.hot")
    26	
  > 27	static DEFINE_STATIC_KEY_FALSE(ftrace_graph_enable);
    28	#ifdef CONFIG_FUNCTION_GRAPH_TRACER
    29	/*
    30	 * Hook the return address and push it in the stack of return addrs
    31	 * in current thread info.
    32	 */
    33	static void __hot prepare_ftrace_return(unsigned long *parent,
    34						unsigned long self_addr)
    35	{
    36		unsigned long old;
    37		extern int parisc_return_to_handler;
    38	
    39		if (unlikely(ftrace_graph_is_dead()))
    40			return;
    41	
    42		if (unlikely(atomic_read(&current->tracing_graph_pause)))
    43			return;
    44	
    45		old = *parent;
    46	
    47		if (!function_graph_enter(old, self_addr, 0, NULL))
    48			/* activate parisc_return_to_handler() as return point */
    49			*parent = (unsigned long) &parisc_return_to_handler;
    50	}
    51	#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
    52	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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