tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
head:   da637905e47dd1eea1683f8cd0a36e359bc46237
commit: 95b61bfed8291e54f65e1fc836c5f9b49f74068c [39/67] hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
config: riscv-randconfig-r016-20221002
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920)
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 riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?id=95b61bfed8291e54f65e1fc836c5f9b49f74068c
        git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
        git fetch --no-tags akpm-mm mm-unstable
        git checkout 95b61bfed8291e54f65e1fc836c5f9b49f74068c
        # 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=riscv 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/hugetlb.c:6835:6: warning: no previous prototype for function '__hugetlb_vma_unlock_write_put' [-Wmissing-prototypes]
   void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
        ^
   mm/hugetlb.c:6835:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
   ^
   static 
   1 warning generated.


vim +/__hugetlb_vma_unlock_write_put +6835 mm/hugetlb.c

  6834	
> 6835	void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
  6836	{
  6837		struct vm_area_struct *vma = vma_lock->vma;
  6838	
  6839		/*
  6840		 * vma_lock structure may or not be released as a result of put,
  6841		 * it certainly will no longer be attached to vma so clear pointer.
  6842		 * Semaphore synchronizes access to vma_lock->vma field.
  6843		 */
  6844		vma_lock->vma = NULL;
  6845		vma->vm_private_data = NULL;
  6846		up_write(&vma_lock->rw_sema);
  6847		kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
  6848	}
  6849	

-- 
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