Re: [PATCH] lib/stackdepot: Use page allocator if both slab and memblock is unavailable

[kernel test robot <lkp@xxxxxxxxx>]

Hi Hyeonggon,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.17-rc5 next-20220225]
[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]

url:    https://github.com/0day-ci/linux/commits/Hyeonggon-Yoo/lib-stackdepot-Use-page-allocator-if-both-slab-and-memblock-is-unavailable/20220227-111029
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2293be58d6a18cab800e25e42081bacb75c05752
config: hexagon-randconfig-r005-20220227 (https://download.01.org/0day-ci/archive/20220227/202202271324.VLaJlMYW-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
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://github.com/0day-ci/linux/commit/fd37f88eccc357002cc03a6a5fac60fb42552bc7
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Hyeonggon-Yoo/lib-stackdepot-Use-page-allocator-if-both-slab-and-memblock-is-unavailable/20220227-111029
        git checkout fd37f88eccc357002cc03a6a5fac60fb42552bc7
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash

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

All warnings (new ones prefixed by >>):

>> lib/stackdepot.c:187:11: warning: comparison of distinct pointer types ('typeof (size) *' (aka 'unsigned int *') and 'typeof ((1UL << 14) << (11 - 1)) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
                           size = min(size, PAGE_SIZE << (MAX_ORDER - 1));
                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:45:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(x, y, <)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   1 warning generated.


vim +187 lib/stackdepot.c

   168	
   169	/*
   170	 * __ref because of memblock_alloc(), which will not be actually called after
   171	 * the __init code is gone, because at that point slab_is_available() is true
   172	 */
   173	__ref int stack_depot_init(void)
   174	{
   175		static DEFINE_MUTEX(stack_depot_init_mutex);
   176	
   177		mutex_lock(&stack_depot_init_mutex);
   178		if (!stack_depot_disable && !stack_table) {
   179			size_t size = (stack_hash_size * sizeof(struct stack_record *));
   180			int i;
   181	
   182			if (slab_is_available()) {
   183				pr_info("Stack Depot allocating hash table with kvmalloc\n");
   184				stack_table = kvmalloc(size, GFP_KERNEL);
   185			} else if (totalram_pages() > 0) {
   186				/* Reduce size because vmalloc may be unavailable */
 > 187				size = min(size, PAGE_SIZE << (MAX_ORDER - 1));
   188				stack_hash_size = size / sizeof(struct stack_record *);
   189	
   190				pr_info("Stack Depot allocating hash table with __get_free_pages\n");
   191				stack_table = (struct stack_record **)
   192					      __get_free_pages(GFP_KERNEL, get_order(size));
   193			} else {
   194				pr_info("Stack Depot allocating hash table with memblock_alloc\n");
   195				stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
   196			}
   197	
   198			if (stack_table) {
   199				pr_info("Stack Depot hash table size=%u\n", stack_hash_size);
   200				for (i = 0; i < stack_hash_size;  i++)
   201					stack_table[i] = NULL;
   202			} else {
   203				pr_err("Stack Depot hash table allocation failed, disabling\n");
   204				stack_depot_disable = true;
   205				mutex_unlock(&stack_depot_init_mutex);
   206				return -ENOMEM;
   207			}
   208		}
   209		mutex_unlock(&stack_depot_init_mutex);
   210		return 0;
   211	}
   212	EXPORT_SYMBOL_GPL(stack_depot_init);
   213	

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