Hi Jaewon,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mmotm/master]
[also build test ERROR on linus/master v5.6-rc4 next-20200304]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Jaewon-Kim/mm-mmap-show-vm_unmapped_area-error-log/20200304-193159
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: alpha-defconfig (attached as .config)
compiler: alpha-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=alpha 

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

All errors (new ones prefixed by >>):

   In file included from include/linux/printk.h:7:0,
                    from include/linux/kernel.h:15,
                    from include/asm-generic/bug.h:19,
                    from arch/alpha/include/asm/bug.h:23,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:9,
                    from include/linux/pagemap.h:8,
                    from arch/alpha/mm/init.c:10:
   include/linux/mm.h: In function 'vm_unmapped_area':
>> include/linux/kern_levels.h:5:18: error: format '%d' expects argument of type 'int', but argument 3 has type 'long unsigned int' [-Werror=format=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^
   include/linux/kern_levels.h:11:18: note: in expansion of macro 'KERN_SOH'
    #define KERN_ERR KERN_SOH "3" /* error conditions */
                     ^~~~~~~~
   include/linux/printk.h:304:9: note: in expansion of macro 'KERN_ERR'
     printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~
   include/linux/mm.h:2451:3: note: in expansion of macro 'pr_err'
      pr_err("%s err:%d total_vm:0x%lx flags:0x%lx len:0x%lx low:0x%lx high:0x%lx\n",
      ^~~~~~
   In file included from include/linux/pagemap.h:8:0,
                    from arch/alpha/mm/init.c:10:
   include/linux/mm.h:2451:19: note: format string is defined here
      pr_err("%s err:%d total_vm:0x%lx flags:0x%lx len:0x%lx low:0x%lx high:0x%lx\n",
                     ~^
                     %ld
   cc1: all warnings being treated as errors

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(a)lists.01.org