Re: [PATCH 4/5] mm/vma: move stack expansion logic to mm/vma.c

[kernel test robot <lkp@intel.com>]

Hi Lorenzo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-vma-move-brk-internals-to-mm-vma-c/20241204-115150
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/0feb104eff85922019d4fb29280f3afb130c5204.1733248985.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 4/5] mm/vma: move stack expansion logic to mm/vma.c
config: x86_64-randconfig-161-20241205 (https://download.01.org/0day-ci/archive/20241205/202412052111.B5Jmi2yT-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)

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/202412052111.B5Jmi2yT-lkp@intel.com/

smatch warnings:
mm/vma.c:2816 expand_downwards() warn: unsigned 'address' is never less than zero.

vim +/address +2816 mm/vma.c

  2798	
  2799	/*
  2800	 * vma is the first one with address < vma->vm_start.  Have to extend vma.
  2801	 * mmap_lock held for writing.
  2802	 */
  2803	int expand_downwards(struct vm_area_struct *vma, unsigned long address)
  2804	{
  2805		struct mm_struct *mm = vma->vm_mm;
  2806		struct vm_area_struct *prev;
  2807		int error = 0;
  2808		VMA_ITERATOR(vmi, mm, vma->vm_start);
  2809	
  2810		if (!(vma->vm_flags & VM_GROWSDOWN))
  2811			return -EFAULT;
  2812	
  2813		mmap_assert_write_locked(mm);
  2814	
  2815		address &= PAGE_MASK;
> 2816		if (address < mmap_min_addr || address < FIRST_USER_ADDRESS)

-- 
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