Re: [RFC PATCH v3 05/16] powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries

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

Hi Christophe,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/fixes arm64/for-next/core v6.9]
[cannot apply to akpm-mm/mm-everything s390/features linus/master next-20240523]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Christophe-Leroy/powerpc-64e-Remove-unused-IBM-HTW-code-SQUASHED/20240526-172511
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
patch link:    https://lore.kernel.org/r/aa54834e9ee5e40179def32ff5834a8a2a02c413.1716714720.git.christophe.leroy%40csgroup.eu
patch subject: [RFC PATCH v3 05/16] powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries
config: powerpc-randconfig-001-20240526 (https://download.01.org/0day-ci/archive/20240526/202405262205.rweOWRhx-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240526/202405262205.rweOWRhx-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/202405262205.rweOWRhx-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/powerpc/mm/pgtable.c:503:18: warning: variable 'pdshift' is uninitialized when used here [-Wuninitialized]
     503 |                 *hpage_shift = pdshift;
         |                                ^~~~~~~
   arch/powerpc/mm/pgtable.c:392:18: note: initialize the variable 'pdshift' to silence this warning
     392 |         unsigned pdshift;
         |                         ^
         |                          = 0
   1 warning generated.


vim +/pdshift +503 arch/powerpc/mm/pgtable.c

a00196a27216133 Nicholas Piggin   2019-06-07  475  
0caed4de502c769 Christophe Leroy  2019-04-26  476  	if (pmd_trans_huge(pmd) || pmd_devmap(pmd)) {
0caed4de502c769 Christophe Leroy  2019-04-26  477  		if (is_thp)
0caed4de502c769 Christophe Leroy  2019-04-26  478  			*is_thp = true;
0caed4de502c769 Christophe Leroy  2019-04-26  479  		ret_pte = (pte_t *)pmdp;
0caed4de502c769 Christophe Leroy  2019-04-26  480  		goto out;
0caed4de502c769 Christophe Leroy  2019-04-26  481  	}
d6eacedd1f0ebf0 Aneesh Kumar K.V  2019-05-14  482  
bd18b688220c722 Peter Xu          2024-03-05  483  	if (pmd_leaf(pmd)) {
0caed4de502c769 Christophe Leroy  2019-04-26  484  		ret_pte = (pte_t *)pmdp;
0caed4de502c769 Christophe Leroy  2019-04-26  485  		goto out;
fab9a1165bcda99 Christophe Leroy  2019-04-26  486  	}
d6eacedd1f0ebf0 Aneesh Kumar K.V  2019-05-14  487  
fab9a1165bcda99 Christophe Leroy  2019-04-26  488  	if (is_hugepd(__hugepd(pmd_val(pmd)))) {
0caed4de502c769 Christophe Leroy  2019-04-26  489  		hpdp = (hugepd_t *)&pmd;
fab9a1165bcda99 Christophe Leroy  2019-04-26  490  		goto out_huge;
fab9a1165bcda99 Christophe Leroy  2019-04-26  491  	}
fab9a1165bcda99 Christophe Leroy  2019-04-26  492  
0caed4de502c769 Christophe Leroy  2019-04-26  493  	return pte_offset_kernel(&pmd, ea);
26e66b08c3376b6 Christophe Leroy  2019-04-26  494  
fab9a1165bcda99 Christophe Leroy  2019-04-26  495  out_huge:
0caed4de502c769 Christophe Leroy  2019-04-26  496  	if (!hpdp)
0caed4de502c769 Christophe Leroy  2019-04-26  497  		return NULL;
0caed4de502c769 Christophe Leroy  2019-04-26  498  
0caed4de502c769 Christophe Leroy  2019-04-26  499  	ret_pte = hugepte_offset(*hpdp, ea, pdshift);
0caed4de502c769 Christophe Leroy  2019-04-26  500  	pdshift = hugepd_shift(*hpdp);
0caed4de502c769 Christophe Leroy  2019-04-26  501  out:
0caed4de502c769 Christophe Leroy  2019-04-26  502  	if (hpage_shift)
0caed4de502c769 Christophe Leroy  2019-04-26 @503  		*hpage_shift = pdshift;
0caed4de502c769 Christophe Leroy  2019-04-26  504  	return ret_pte;
0caed4de502c769 Christophe Leroy  2019-04-26  505  }
0caed4de502c769 Christophe Leroy  2019-04-26  506  EXPORT_SYMBOL_GPL(__find_linux_pte);
6eac1eaf2105dd8 Anshuman Khandual 2022-07-11  507  

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