Re: [PATCH next 2/2] mm/huge_memory: Add sysfs knob for executable THP COW

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

Hi Zhang,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20251215]

url:    https://github.com/intel-lab-lkp/linux/commits/Zhang-Qilong/mm-huge_memory-Implementation-of-THP-COW-for-executable-file-mmap/20251215-204035
base:   next-20251215
patch link:    https://lore.kernel.org/r/20251215123407.380813-3-zhangqilong3%40huawei.com
patch subject: [PATCH next 2/2] mm/huge_memory: Add sysfs knob for executable THP COW
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20251216/202512161231.CTAFQzip-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251216/202512161231.CTAFQzip-lkp@intel.com/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/202512161231.CTAFQzip-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/memory.c:6131:6: error: call to undeclared function 'transparent_hugepage_use_exec_cow'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    6131 |         if (transparent_hugepage_use_exec_cow() &&
         |             ^
   mm/memory.c:6135:7: error: call to undeclared function 'vma_is_special_huge'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    6135 |                 if (vma_is_special_huge(vma) || vma_is_shmem(vma))
         |                     ^
   2 errors generated.


vim +/transparent_hugepage_use_exec_cow +6131 mm/memory.c

  6104	
  6105	/* `inline' is required to avoid gcc 4.1.2 build error */
  6106	static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
  6107	{
  6108		struct vm_area_struct *vma = vmf->vma;
  6109		const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE;
  6110		vm_fault_t ret;
  6111	
  6112		if (vma_is_anonymous(vma)) {
  6113			if (likely(!unshare) &&
  6114			    userfaultfd_huge_pmd_wp(vma, vmf->orig_pmd)) {
  6115				if (userfaultfd_wp_async(vmf->vma))
  6116					goto split;
  6117				return handle_userfault(vmf, VM_UFFD_WP);
  6118			}
  6119			return do_huge_pmd_wp_page(vmf);
  6120		}
  6121	
  6122		if (vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) {
  6123			if (vma->vm_ops->huge_fault) {
  6124				ret = vma->vm_ops->huge_fault(vmf, PMD_ORDER);
  6125				if (!(ret & VM_FAULT_FALLBACK))
  6126					return ret;
  6127			}
  6128		}
  6129	
  6130	
> 6131		if (transparent_hugepage_use_exec_cow() &&
  6132		    is_exec_mapping(vma->vm_flags) &&
  6133		    is_cow_mapping(vma->vm_flags)) {
  6134			/* Skip special and shmem */
  6135			if (vma_is_special_huge(vma) || vma_is_shmem(vma))
  6136				goto split;
  6137	
  6138			ret = do_huge_pmd_exec_cow(vmf);
  6139			if (!(ret & VM_FAULT_FALLBACK))
  6140				return ret;
  6141		}
  6142	
  6143	split:
  6144		/* COW or write-notify handled on pte level: split pmd. */
  6145		__split_huge_pmd(vma, vmf->pmd, vmf->address, false);
  6146	
  6147		return VM_FAULT_FALLBACK;
  6148	}
  6149	

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