Re: [PATCH] lib/stackdepot.c: use a non-instrumented version of memcpy()

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

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Hi Alexander,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17-rc5 next-20180517]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Alexander-Potapenko/lib-stackdepot-c-use-a-non-instrumented-version-of-memcpy/20180518-015328
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=sh 

All errors (new ones prefixed by >>):

   lib/stackdepot.c: In function 'depot_alloc_stack':
>> lib/stackdepot.c:143:2: error: implicit declaration of function '__memcpy'; did you mean 'memcpy'? [-Werror=implicit-function-declaration]
     __memcpy(stack->entries, entries, size * sizeof(unsigned long));
     ^~~~~~~~
     memcpy
   cc1: some warnings being treated as errors

vim +143 lib/stackdepot.c

   106	
   107	/* Allocation of a new stack in raw storage */
   108	static struct stack_record *depot_alloc_stack(unsigned long *entries, int size,
   109			u32 hash, void **prealloc, gfp_t alloc_flags)
   110	{
   111		int required_size = offsetof(struct stack_record, entries) +
   112			sizeof(unsigned long) * size;
   113		struct stack_record *stack;
   114	
   115		required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN);
   116	
   117		if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) {
   118			if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) {
   119				WARN_ONCE(1, "Stack depot reached limit capacity");
   120				return NULL;
   121			}
   122			depot_index++;
   123			depot_offset = 0;
   124			/*
   125			 * smp_store_release() here pairs with smp_load_acquire() from
   126			 * |next_slab_inited| in depot_save_stack() and
   127			 * init_stack_slab().
   128			 */
   129			if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
   130				smp_store_release(&next_slab_inited, 0);
   131		}
   132		init_stack_slab(prealloc);
   133		if (stack_slabs[depot_index] == NULL)
   134			return NULL;
   135	
   136		stack = stack_slabs[depot_index] + depot_offset;
   137	
   138		stack->hash = hash;
   139		stack->size = size;
   140		stack->handle.slabindex = depot_index;
   141		stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
   142		stack->handle.valid = 1;
 > 143		__memcpy(stack->entries, entries, size * sizeof(unsigned long));
   144		depot_offset += required_size;
   145	
   146		return stack;
   147	}
   148	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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