Re: [PATCH] prctl: Add PR_GET_AUXV to copy auxv to userspace

[kernel test robot]

Hi Josh,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.3-rc5]
[cannot apply to akpm-mm/mm-everything next-20230404]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Josh-Triplett/prctl-Add-PR_GET_AUXV-to-copy-auxv-to-userspace/20230404-140043
patch link:    https://lore.kernel.org/r/b11a591e085f1cd06adb454b1f7cde676d317318.1680585798.git.josh%40joshtriplett.org
patch subject: [PATCH] prctl: Add PR_GET_AUXV to copy auxv to userspace
config: arm-randconfig-r025-20230403 (https://download.01.org/0day-ci/archive/20230404/202304041710.JYcSAmPL-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/intel-lab-lkp/linux/commit/4323f9bd6c2ecbfd6be4f8a3830ea47a89558314
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Josh-Triplett/prctl-Add-PR_GET_AUXV-to-copy-auxv-to-userspace/20230404-140043
        git checkout 4323f9bd6c2ecbfd6be4f8a3830ea47a89558314
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Link: https://lore.kernel.org/oe-kbuild-all/202304041710.JYcSAmPL-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> kernel/sys.c:2383:23: warning: comparison of distinct pointer types ('typeof (sizeof (mm->saved_auxv)) *' (aka 'unsigned int *') and 'typeof (len) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
           unsigned long size = min(sizeof(mm->saved_auxv), len);
                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(x, y, <)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   1 warning generated.


vim +2383 kernel/sys.c

  2379	
  2380	static int prctl_get_auxv(void __user *addr, unsigned long len)
  2381	{
  2382		struct mm_struct *mm = current->mm;
> 2383		unsigned long size = min(sizeof(mm->saved_auxv), len);
  2384	
  2385		if (size && copy_to_user(addr, mm->saved_auxv, size))
  2386			return -EFAULT;
  2387		return sizeof(mm->saved_auxv);
  2388	}
  2389	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests