On Wed, Dec 09, 2020 at 01:36:50PM +0800, kernel test robot wrote:
> 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'

I will find a spot in mm/slab.c that is not under #ifdef sooner or
later...  Fix queued.  ;-)

							Thanx, Paul

> 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(a)lists.01.org