tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2020.06.02a
head:   5216948905dd07a84cef8a7dc72c2ec076802efd
commit: 7d16add62717136b1839f0b3d7ea4cbb98f38c2a [67/90] rcuperf: Fix kfree_mult to match printk() format
config: parisc-randconfig-r022-20200607 (attached as .config)
compiler: hppa-linux-gcc (GCC) 9.3.0
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
        git checkout 7d16add62717136b1839f0b3d7ea4cbb98f38c2a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc 

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

All warnings (new ones prefixed by >>, old ones prefixed by <<):

In file included from include/linux/mm.h:95,
from kernel/rcu/rcuperf.c:15:
include/asm-generic/pgtable.h: In function 'pte_clear_not_present_full':
arch/parisc/include/asm/pgtable.h:96:9: warning: variable 'old_pte' set but not used [-Wunused-but-set-variable]
96 |   pte_t old_pte;              |         ^~~~~~~
arch/parisc/include/asm/pgtable.h:322:34: note: in expansion of macro 'set_pte_at'
322 | #define pte_clear(mm, addr, xp)  set_pte_at(mm, addr, xp, __pte(0))
|                                  ^~~~~~~~~~
include/asm-generic/pgtable.h:202:2: note: in expansion of macro 'pte_clear'
202 |  pte_clear(mm, address, ptep);
|  ^~~~~~~~~
include/asm-generic/pgtable.h: In function '__ptep_modify_prot_commit':
arch/parisc/include/asm/pgtable.h:96:9: warning: variable 'old_pte' set but not used [-Wunused-but-set-variable]
96 |   pte_t old_pte;              |         ^~~~~~~
include/asm-generic/pgtable.h:641:2: note: in expansion of macro 'set_pte_at'
641 |  set_pte_at(vma->vm_mm, addr, ptep, pte);
|  ^~~~~~~~~~
In file included from include/linux/printk.h:7,
from include/linux/kernel.h:15,
from kernel/rcu/rcuperf.c:13:
kernel/rcu/rcuperf.c: In function 'kfree_perf_init':
>> include/linux/kern_levels.h:5:18: warning: format '%zu' expects argument of type 'size_t', but argument 2 has type 'long unsigned int' [-Wformat=]
5 | #define KERN_SOH "001"  /* ASCII Start Of Header */
|                  ^~~~~~
include/linux/kern_levels.h:9:20: note: in expansion of macro 'KERN_SOH'
9 | #define KERN_ALERT KERN_SOH "1" /* action must be taken immediately */
|                    ^~~~~~~~
include/linux/printk.h:295:9: note: in expansion of macro 'KERN_ALERT'
295 |  printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
|         ^~~~~~~~~~
kernel/rcu/rcuperf.c:727:2: note: in expansion of macro 'pr_alert'
727 |  pr_alert("kfree object size=%zun", kfree_mult * sizeof(struct kfree_obj));
|  ^~~~~~~~
kernel/rcu/rcuperf.c:727:32: note: format string is defined here
727 |  pr_alert("kfree object size=%zun", kfree_mult * sizeof(struct kfree_obj));
|                              ~~^
|                                |
|                                unsigned int
|                              %lu

vim +5 include/linux/kern_levels.h

314ba3520e513a Joe Perches 2012-07-30  4  
04d2c8c83d0e3a Joe Perches 2012-07-30 @5  #define KERN_SOH	"\001"		/* ASCII Start Of Header */
04d2c8c83d0e3a Joe Perches 2012-07-30  6  #define KERN_SOH_ASCII	'\001'
04d2c8c83d0e3a Joe Perches 2012-07-30  7  

:::::: The code at line 5 was first introduced by commit
:::::: 04d2c8c83d0e3ac5f78aeede51babb3236200112 printk: convert the format for KERN_<LEVEL> to a 2 byte pattern

:::::: TO: Joe Perches <joe@perches.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

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