Hi,

I love your patch! Yet something to improve:

[auto build test ERROR on linux/master]
[also build test ERROR on linus/master hnaz-linux-mm/master v5.10-rc7]
[cannot apply to mmotm/master rcu/dev rcu/rcu/next next-20201208]
[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/paulmck-kernel-org/mm-Add-mem_dump_obj-to-print-source-of-memory-block/20201209-091546
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 09162bc32c880a791c6c0668ce0745cf7958f576
config: x86_64-randconfig-a004-20201208 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/c49050a9b3235279954c0b5d82abd90fa09d9359
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review paulmck-kernel-org/mm-Add-mem_dump_obj-to-print-source-of-memory-block/20201209-091546
        git checkout c49050a9b3235279954c0b5d82abd90fa09d9359
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

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

All errors (new ones prefixed by >>):

   ld: mm/slab_common.o: in function `kmem_dump_obj':
>> mm/slab_common.c:589: undefined reference to `kmem_provenance'

vim +589 mm/slab_common.c

   557	
   558	/**
   559	 * kmem_dump_obj - Print available slab provenance information
   560	 * @object: slab object for which to find provenance information.
   561	 *
   562	 * This function uses pr_cont(), so that the caller is expected to have
   563	 * printed out whatever preamble is appropriate.  The provenance information
   564	 * depends on the type of object and on how much debugging is enabled.
   565	 * For a slab-cache object, the fact that it is a slab object is printed,
   566	 * and, if available, the slab name, return address, and stack trace from
   567	 * the allocation of that object.
   568	 *
   569	 * This function will splat if passed a pointer to a non-slab object.
   570	 * If you are not sure what type of object you have, you should instead
   571	 * use mem_dump_obj().
   572	 */
   573	void kmem_dump_obj(void *object)
   574	{
   575		int i;
   576		struct page *page;
   577		struct kmem_provenance kp;
   578	
   579		if (WARN_ON_ONCE(!virt_addr_valid(object)))
   580			return;
   581		page = virt_to_head_page(object);
   582		if (WARN_ON_ONCE(!PageSlab(page))) {
   583			pr_cont(" non-slab memory.\n");
   584			return;
   585		}
   586		kp.kp_ptr = object;
   587		kp.kp_page = page;
   588		kp.kp_nstack = KS_ADDRS_COUNT;
 > 589		kmem_provenance(&kp);
   590		if (page->slab_cache)
   591			pr_cont(" slab %s", page->slab_cache->name);
   592		else
   593			pr_cont(" slab ");
   594		if (kp.kp_ret)
   595			pr_cont(" allocated at %pS\n", kp.kp_ret);
   596		else
   597			pr_cont("\n");
   598		if (kp.kp_stack[0]) {
   599			for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
   600				if (!kp.kp_stack[i])
   601					break;
   602				pr_info("    %pS\n", kp.kp_stack[i]);
   603			}
   604		}
   605	}
   606	EXPORT_SYMBOL_GPL(kmem_dump_obj);
   607	

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