[daveh-devel:kpte 2/6] include/asm-generic/pgalloc.h:144:21: warning: variable 'ptdesc' is uninitialized when used here

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/daveh/devel.git kpte
head:   d5eaa925a3150c716e8ec564c51069fbdd303fbc
commit: ccbd04de39826d130b67374e68599e128b53acab [2/6] mm: Actually mark kernel page table pages
config: x86_64-buildonly-randconfig-004-20250829 (https://download.01.org/0day-ci/archive/20250829/202508292320.plYGOdi2-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/20250829/202508292320.plYGOdi2-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/202508292320.plYGOdi2-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from kernel/fork.c:110:
   In file included from arch/x86/include/asm/pgalloc.h:13:
>> include/asm-generic/pgalloc.h:144:21: warning: variable 'ptdesc' is uninitialized when used here [-Wuninitialized]
     144 |                 ptdesc_set_kernel(ptdesc);
         |                                   ^~~~~~
   include/asm-generic/pgalloc.h:139:23: note: initialize the variable 'ptdesc' to silence this warning
     139 |         struct ptdesc *ptdesc;
         |                              ^
         |                               = NULL
   include/asm-generic/pgalloc.h:179:21: warning: variable 'ptdesc' is uninitialized when used here [-Wuninitialized]
     179 |                 ptdesc_set_kernel(ptdesc);
         |                                   ^~~~~~
   include/asm-generic/pgalloc.h:175:23: note: initialize the variable 'ptdesc' to silence this warning
     175 |         struct ptdesc *ptdesc;
         |                              ^
         |                               = NULL
   include/asm-generic/pgalloc.h:235:21: warning: variable 'ptdesc' is uninitialized when used here [-Wuninitialized]
     235 |                 ptdesc_set_kernel(ptdesc);
         |                                   ^~~~~~
   include/asm-generic/pgalloc.h:231:23: note: initialize the variable 'ptdesc' to silence this warning
     231 |         struct ptdesc *ptdesc;
         |                              ^
         |                               = NULL
   include/asm-generic/pgalloc.h:281:21: warning: variable 'ptdesc' is uninitialized when used here [-Wuninitialized]
     281 |                 ptdesc_set_kernel(ptdesc);
         |                                   ^~~~~~
   include/asm-generic/pgalloc.h:277:23: note: initialize the variable 'ptdesc' to silence this warning
     277 |         struct ptdesc *ptdesc;
         |                              ^
         |                               = NULL
   4 warnings generated.


vim +/ptdesc +144 include/asm-generic/pgalloc.h

   124	
   125	#ifndef __HAVE_ARCH_PMD_ALLOC_ONE
   126	/**
   127	 * pmd_alloc_one - allocate memory for a PMD-level page table
   128	 * @mm: the mm_struct of the current context
   129	 *
   130	 * Allocate memory for a page table and ptdesc and runs pagetable_pmd_ctor().
   131	 *
   132	 * Allocations use %GFP_PGTABLE_USER in user context and
   133	 * %GFP_PGTABLE_KERNEL in kernel context.
   134	 *
   135	 * Return: pointer to the allocated memory or %NULL on error
   136	 */
   137	static inline pmd_t *pmd_alloc_one_noprof(struct mm_struct *mm, unsigned long addr)
   138	{
   139		struct ptdesc *ptdesc;
   140		gfp_t gfp = GFP_PGTABLE_USER;
   141	
   142		if (mm == &init_mm) {
   143			gfp = GFP_PGTABLE_KERNEL;
 > 144			ptdesc_set_kernel(ptdesc);
   145		}
   146		ptdesc = pagetable_alloc_noprof(gfp, 0);
   147		if (!ptdesc)
   148			return NULL;
   149		if (!pagetable_pmd_ctor(mm, ptdesc)) {
   150			pagetable_free(ptdesc);
   151			return NULL;
   152		}
   153		return ptdesc_address(ptdesc);
   154	}
   155	#define pmd_alloc_one(...)	alloc_hooks(pmd_alloc_one_noprof(__VA_ARGS__))
   156	#endif
   157	

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