[chunkuang-hu:pagecaller 3/3] mm/vmstat.c:1548:30: warning: unused variable 'symbol'

[chunkuang-hu:pagecaller 3/3] mm/vmstat.c:1548:30: warning: unused variable 'symbol'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git pagecaller
head:   7b43af7f4b48c1abb6df811dbaa644a0c7800366
commit: 7b43af7f4b48c1abb6df811dbaa644a0c7800366 [3/3] mm: vmstat: add pagecaller information
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20220714/202207141128.kaFVoGy9-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/commit/?id=7b43af7f4b48c1abb6df811dbaa644a0c7800366
        git remote add chunkuang-hu https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git
        git fetch --no-tags chunkuang-hu pagecaller
        git checkout 7b43af7f4b48c1abb6df811dbaa644a0c7800366
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   mm/vmstat.c: In function 'dump_pagecaller':
   mm/vmstat.c:1548:37: error: 'KSYM_SYMBOL_LEN' undeclared (first use in this function)
    1548 |                         char symbol[KSYM_SYMBOL_LEN];
         |                                     ^~~~~~~~~~~~~~~
   mm/vmstat.c:1548:37: note: each undeclared identifier is reported only once for each function it appears in
   mm/vmstat.c:1549:25: error: implicit declaration of function 'kallsyms_lookup' [-Werror=implicit-function-declaration]
    1549 |                         kallsyms_lookup(pagecaller[i], NULL, NULL, NULL, symbol);
         |                         ^~~~~~~~~~~~~~~
>> mm/vmstat.c:1548:30: warning: unused variable 'symbol' [-Wunused-variable]
    1548 |                         char symbol[KSYM_SYMBOL_LEN];
         |                              ^~~~~~
   cc1: some warnings being treated as errors


vim +/symbol +1548 mm/vmstat.c

  1531	
  1532	static void dump_pagecaller(struct seq_file *m)
  1533	{
  1534		unsigned long i;
  1535	
  1536		seq_printf(m, "max_pfn = %lu\n", max_pfn);
  1537		seq_printf(m, "pagecaller_nr = %lu\n", pagecaller_nr);
  1538	
  1539		for (i = 0; i < pagecaller_nr; i++)
  1540			if (pagecaller[i] == 0) {
  1541				seq_printf(m, "0x%016lx %16lu [Free memory]\n",
  1542					   pagecaller[i], pagecaller_cnt[i] * 4);
  1543			} else if (pagecaller[i] == 0xffffffffffffffff) {
  1544				seq_printf(m, "0x%016lx %16lu [Reserved memory]\n",
  1545					   pagecaller[i], pagecaller_cnt[i] * 4);
  1546			} else {
  1547	#ifdef CONFIG_KALLSYMS
> 1548				char symbol[KSYM_SYMBOL_LEN];
  1549				kallsyms_lookup(pagecaller[i], NULL, NULL, NULL, symbol);
  1550				seq_printf(m, "0x%016lx %16lu %s\n", pagecaller[i],
  1551					   pagecaller_cnt[i] * 4, symbol);
  1552	#else
  1553				seq_printf(m, "0x%016lx %16lu\n", pagecaller[i],
  1554					   pagecaller_cnt[i] * 4);
  1555	#endif
  1556			}
  1557	}
  1558	

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