kernel/fork.c:1181: warning: Function parameter or member 'mm' not described in 'replace_mm_exe_file'

[kernel test robot <philip.li@intel.com>]

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   708283abf896dd4853e673cc8cba70acaf9bf4ea
commit: 35d7bdc86031a2c1ae05ac27dfa93b2acdcbaecc kernel/fork: factor out replacing the current MM exe_file
date:   2 years ago
:::::: branch date: 5 hours ago
:::::: commit date: 2 years ago
config: i386-allnoconfig (attached as .config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (attached as reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309040758.TJlCtQvv-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/fork.c:1154: warning: Function parameter or member 'mm' not described in 'set_mm_exe_file'
   kernel/fork.c:1154: warning: Function parameter or member 'new_exe_file' not described in 'set_mm_exe_file'
>> kernel/fork.c:1181: warning: Function parameter or member 'mm' not described in 'replace_mm_exe_file'
>> kernel/fork.c:1181: warning: Function parameter or member 'new_exe_file' not described in 'replace_mm_exe_file'
   kernel/fork.c:1218: warning: Function parameter or member 'mm' not described in 'get_mm_exe_file'
   kernel/fork.c:1238: warning: Function parameter or member 'task' not described in 'get_task_exe_file'
   kernel/fork.c:1263: warning: Function parameter or member 'task' not described in 'get_task_mm'
   kernel/fork.c:2807: warning: expecting prototype for clone3(). Prototype was for sys_clone3() instead


vim +1181 kernel/fork.c

3864601387cf419 Jiri Slaby        2011-05-26  1170  
35d7bdc86031a2c David Hildenbrand 2021-04-23  1171  /**
35d7bdc86031a2c David Hildenbrand 2021-04-23  1172   * replace_mm_exe_file - replace a reference to the mm's executable file
35d7bdc86031a2c David Hildenbrand 2021-04-23  1173   *
35d7bdc86031a2c David Hildenbrand 2021-04-23  1174   * This changes mm's executable file (shown as symlink /proc/[pid]/exe),
35d7bdc86031a2c David Hildenbrand 2021-04-23  1175   * dealing with concurrent invocation and without grabbing the mmap lock in
35d7bdc86031a2c David Hildenbrand 2021-04-23  1176   * write mode.
35d7bdc86031a2c David Hildenbrand 2021-04-23  1177   *
35d7bdc86031a2c David Hildenbrand 2021-04-23  1178   * Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE).
35d7bdc86031a2c David Hildenbrand 2021-04-23  1179   */
35d7bdc86031a2c David Hildenbrand 2021-04-23  1180  int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
35d7bdc86031a2c David Hildenbrand 2021-04-23 @1181  {
35d7bdc86031a2c David Hildenbrand 2021-04-23  1182  	struct vm_area_struct *vma;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1183  	struct file *old_exe_file;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1184  	int ret = 0;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1185  
35d7bdc86031a2c David Hildenbrand 2021-04-23  1186  	/* Forbid mm->exe_file change if old file still mapped. */
35d7bdc86031a2c David Hildenbrand 2021-04-23  1187  	old_exe_file = get_mm_exe_file(mm);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1188  	if (old_exe_file) {
35d7bdc86031a2c David Hildenbrand 2021-04-23  1189  		mmap_read_lock(mm);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1190  		for (vma = mm->mmap; vma && !ret; vma = vma->vm_next) {
35d7bdc86031a2c David Hildenbrand 2021-04-23  1191  			if (!vma->vm_file)
35d7bdc86031a2c David Hildenbrand 2021-04-23  1192  				continue;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1193  			if (path_equal(&vma->vm_file->f_path,
35d7bdc86031a2c David Hildenbrand 2021-04-23  1194  				       &old_exe_file->f_path))
35d7bdc86031a2c David Hildenbrand 2021-04-23  1195  				ret = -EBUSY;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1196  		}
35d7bdc86031a2c David Hildenbrand 2021-04-23  1197  		mmap_read_unlock(mm);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1198  		fput(old_exe_file);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1199  		if (ret)
35d7bdc86031a2c David Hildenbrand 2021-04-23  1200  			return ret;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1201  	}
35d7bdc86031a2c David Hildenbrand 2021-04-23  1202  
35d7bdc86031a2c David Hildenbrand 2021-04-23  1203  	/* set the new file, lockless */
35d7bdc86031a2c David Hildenbrand 2021-04-23  1204  	get_file(new_exe_file);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1205  	old_exe_file = xchg(&mm->exe_file, new_exe_file);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1206  	if (old_exe_file)
35d7bdc86031a2c David Hildenbrand 2021-04-23  1207  		fput(old_exe_file);
35d7bdc86031a2c David Hildenbrand 2021-04-23  1208  	return 0;
35d7bdc86031a2c David Hildenbrand 2021-04-23  1209  }
35d7bdc86031a2c David Hildenbrand 2021-04-23  1210  

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

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[-- Attachment #3: reproduce --]
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reproduce (this is a W=1 build):
        mkdir -p ~/bin
        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/torvalds/linux.git/commit/?id=35d7bdc86031a2c1ae05ac27dfa93b2acdcbaecc
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 35d7bdc86031a2c1ae05ac27dfa93b2acdcbaecc
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash