Re: [PATCH v4 5/6] mm: cma: add cma_alloc_frozen{_compound}()

[Kefeng Wang <wangkefeng.wang@huawei.com>]

On 2025/12/20 22:34, kernel test robot wrote:
> Hi Kefeng,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on akpm-mm/mm-everything]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Kefeng-Wang/mm-debug_vm_pgtable-add-debug_vm_pgtable_free_huge_page/20251216-195027
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20251216114844.2126250-6-wangkefeng.wang%40huawei.com
> patch subject: [PATCH v4 5/6] mm: cma: add cma_alloc_frozen{_compound}()
> config: s390-randconfig-r053-20251218 (https://download.01.org/0day-ci/archive/20251220/202512202141.mGkUgIRF-lkp@intel.com/config)
> compiler: s390-linux-gcc (GCC) 8.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251220/202512202141.mGkUgIRF-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/202512202141.mGkUgIRF-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>     mm/hugetlb_cma.c: In function 'hugetlb_cma_alloc_folio':
>>> mm/hugetlb_cma.c:44:11: warning: array subscript [0, 0] is outside array bounds of 'struct cma *[1]' [-Warray-bounds]
>         page = cma_alloc_frozen_compound(hugetlb_cma[nid], order);
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Kconfig warnings: (for reference only)
>     WARNING: unmet direct dependencies detected for CAN_DEV
>     Depends on [n]: NETDEVICES [=n] && CAN [=m]
>     Selected by [m]:
>     - CAN [=m] && NET [=y]
> 
> 
> vim +44 mm/hugetlb_cma.c
> 
>      28	
>      29	struct folio *hugetlb_cma_alloc_folio(int order, gfp_t gfp_mask,
>      30					      int nid, nodemask_t *nodemask)
>      31	{
>      32		int node;
>      33		struct folio *folio;
>      34		struct page *page = NULL;
>      35	
>      36		if (hugetlb_cma[nid])
>      37			page = cma_alloc_frozen_compound(hugetlb_cma[nid], order);
>      38	
>      39		if (!page && !(gfp_mask & __GFP_THISNODE)) {
>      40			for_each_node_mask(node, *nodemask) {
>      41				if (node == nid || !hugetlb_cma[node])
>      42					continue;
>      43	
>    > 44				page = cma_alloc_frozen_compound(hugetlb_cma[nid], order);

Oh, it should be hugetlb_cma[node] in the fallback path, thanks for the 
reporting.