[linux-next:master 3616/3917] mm/sparse-vmemmap.c:69:35: warning: operation on 'pte' may be undefined

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   98546348153dee5f8ced572fd6c4690461d20f51
commit: 342ec54e2df2b6944c883e078cfae855cc33cc31 [3616/3917] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page
config: arm64-randconfig-r001-20210311 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=342ec54e2df2b6944c883e078cfae855cc33cc31
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 342ec54e2df2b6944c883e078cfae855cc33cc31
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

   In file included from arch/arm64/include/asm/memory.h:366,
                    from arch/arm64/include/asm/thread_info.h:17,
                    from include/linux/thread_info.h:58,
                    from arch/arm64/include/asm/preempt.h:5,
                    from include/linux/preempt.h:78,
                    from include/linux/spinlock.h:51,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:6,
                    from include/linux/mm.h:10,
                    from mm/sparse-vmemmap.c:21:
   mm/sparse-vmemmap.c: In function 'vmemmap_pte_range':

quoted

mm/sparse-vmemmap.c:69:35: warning: operation on 'pte' may be undefined [-Wsequence-point]

      69 |   walk->reuse_page = pte_page(*pte++);
         |                                ~~~^~
   include/asm-generic/memory_model.h:54:40: note: in definition of macro '__pfn_to_page'
      54 | #define __pfn_to_page(pfn) (vmemmap + (pfn))
         |                                        ^~~
   arch/arm64/include/asm/pgtable.h:73:4: note: in expansion of macro 'pte_val'
      73 |  ((pte_val(pte) & PTE_ADDR_LOW) | ((pte_val(pte) & PTE_ADDR_HIGH) << 36))
         |    ^~~~~~~
   arch/arm64/include/asm/pgtable.h:80:24: note: in expansion of macro '__pte_to_phys'
      80 | #define pte_pfn(pte)  (__pte_to_phys(pte) >> PAGE_SHIFT)
         |                        ^~~~~~~~~~~~~
   arch/arm64/include/asm/pgtable.h:86:37: note: in expansion of macro 'pte_pfn'
      86 | #define pte_page(pte)  (pfn_to_page(pte_pfn(pte)))
         |                                     ^~~~~~~
   mm/sparse-vmemmap.c:69:22: note: in expansion of macro 'pte_page'
      69 |   walk->reuse_page = pte_page(*pte++);
         |                      ^~~~~~~~


vim +/pte +69 mm/sparse-vmemmap.c

    52	
    53	static void vmemmap_pte_range(pmd_t *pmd, unsigned long addr,
    54				      unsigned long end,
    55				      struct vmemmap_remap_walk *walk)
    56	{
    57		pte_t *pte;
    58	
    59		pte = pte_offset_kernel(pmd, addr);
    60	
    61		/*
    62		 * The reuse_page is found 'first' in table walk before we start
    63		 * remapping (which is calling @walk->remap_pte).
    64		 */
    65		if (!walk->reuse_page) {
    66			BUG_ON(pte_none(*pte));
    67			BUG_ON(walk->reuse_addr != addr);
    68	
  > 69			walk->reuse_page = pte_page(*pte++);
    70			/*
    71			 * Because the reuse address is part of the range that we are
    72			 * walking, skip the reuse address range.
    73			 */
    74			addr += PAGE_SIZE;
    75		}
    76	
    77		for (; addr != end; addr += PAGE_SIZE, pte++) {
    78			BUG_ON(pte_none(*pte));
    79	
    80			walk->remap_pte(pte, addr, walk);
    81		}
    82	}
    83	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org