Re: [PATCH v3 1/2] mm: Abstract THP allocation
From: kernel test robot
Date: Thu Sep 12 2024 - 09:27:37 EST
Hi Dev,
kernel test robot noticed the following build warnings:
[auto build test WARNING on v6.11-rc7]
[also build test WARNING on linus/master]
[cannot apply to akpm-mm/mm-everything next-20240912]
[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/Dev-Jain/mm-Abstract-THP-allocation/20240911-145809
base: v6.11-rc7
patch link: https://lore.kernel.org/r/20240911065600.1002644-2-dev.jain%40arm.com
patch subject: [PATCH v3 1/2] mm: Abstract THP allocation
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240912/202409122144.jqe4JROY-lkp@xxxxxxxxx/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240912/202409122144.jqe4JROY-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409122144.jqe4JROY-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
>> mm/huge_memory.c:1012:6: warning: variable 'pgtable' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
1012 | if (unlikely(!folio)) {
| ^~~~~~~~~~~~~~~~
include/linux/compiler.h:77:22: note: expanded from macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
mm/huge_memory.c:1051:6: note: uninitialized use occurs here
1051 | if (pgtable)
| ^~~~~~~
mm/huge_memory.c:1012:2: note: remove the 'if' if its condition is always false
1012 | if (unlikely(!folio)) {
| ^~~~~~~~~~~~~~~~~~~~~~~
1013 | ret = VM_FAULT_FALLBACK;
| ~~~~~~~~~~~~~~~~~~~~~~~~
1014 | goto release;
| ~~~~~~~~~~~~~
1015 | }
| ~
mm/huge_memory.c:1006:19: note: initialize the variable 'pgtable' to silence this warning
1006 | pgtable_t pgtable;
| ^
| = NULL
1 warning generated.
vim +1012 mm/huge_memory.c
1001
1002 static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf)
1003 {
1004 struct vm_area_struct *vma = vmf->vma;
1005 struct folio *folio;
1006 pgtable_t pgtable;
1007 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
1008 vm_fault_t ret = 0;
1009 gfp_t gfp = vma_thp_gfp_mask(vma);
1010
1011 folio = pmd_thp_fault_alloc(gfp, vma, haddr, vmf->address);
> 1012 if (unlikely(!folio)) {
1013 ret = VM_FAULT_FALLBACK;
1014 goto release;
1015 }
1016
1017 pgtable = pte_alloc_one(vma->vm_mm);
1018 if (unlikely(!pgtable)) {
1019 ret = VM_FAULT_OOM;
1020 goto release;
1021 }
1022
1023 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
1024
1025 if (unlikely(!pmd_none(*vmf->pmd))) {
1026 goto unlock_release;
1027 } else {
1028 ret = check_stable_address_space(vma->vm_mm);
1029 if (ret)
1030 goto unlock_release;
1031
1032 /* Deliver the page fault to userland */
1033 if (userfaultfd_missing(vma)) {
1034 spin_unlock(vmf->ptl);
1035 folio_put(folio);
1036 pte_free(vma->vm_mm, pgtable);
1037 ret = handle_userfault(vmf, VM_UFFD_MISSING);
1038 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
1039 return ret;
1040 }
1041 pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
1042 map_pmd_thp(folio, vmf, vma, haddr);
1043 spin_unlock(vmf->ptl);
1044 __pmd_thp_fault_success_stats(vma);
1045 }
1046
1047 return 0;
1048 unlock_release:
1049 spin_unlock(vmf->ptl);
1050 release:
1051 if (pgtable)
1052 pte_free(vma->vm_mm, pgtable);
1053 if (folio)
1054 folio_put(folio);
1055 return ret;
1056
--
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