Re: [rcu:rcu/next 94/101] mm/slab_common.c:555: undefined reference to `kmem_cache_last_alloc'

[Paul E. McKenney]

On Fri, Dec 04, 2020 at 12:53:56PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu/next
> head:   413d9f332cbd16d951c22a41f2e5f53c1a75ae1c
> commit: f7c3fb4fc476a8a7a3cfc78cffbf1de13c1899b7 [94/101] mm: Add kmem_last_alloc() to return last allocation for memory block
> config: i386-randconfig-p001-20201204 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> reproduce (this is a W=1 build):
>         # https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?id=f7c3fb4fc476a8a7a3cfc78cffbf1de13c1899b7
>         git remote add rcu https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
>         git fetch --no-tags rcu rcu/next
>         git checkout f7c3fb4fc476a8a7a3cfc78cffbf1de13c1899b7
>         # save the attached .config to linux build tree
>         make W=1 ARCH=i386 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> 
> All errors (new ones prefixed by >>):
> 
>    ld: mm/slab_common.o: in function `kmem_last_alloc':
> >> mm/slab_common.c:555: undefined reference to `kmem_cache_last_alloc'
> 
> vim +555 mm/slab_common.c

Good catch!  I had no idea that the slab definition of the
kmem_cache_last_alloc() function was under CONFIG_NUMA...

Will fold a fix in with attribution.

							Thanx, Paul

>    538	
>    539	/*
>    540	 * If the pointer references a slab-allocated object and if sufficient
>    541	 * debugging is enabled, return the returrn address for the corresponding
>    542	 * allocation.  Otherwise, return NULL.  Note that passing random pointers
>    543	 * to this function (including addresses of on-stack variables) is likely
>    544	 * to result in panics.
>    545	 */
>    546	void *kmem_last_alloc(void *object)
>    547	{
>    548		struct page *page;
>    549	
>    550		if (!virt_addr_valid(object))
>    551			return NULL;
>    552		page = virt_to_head_page(object);
>    553		if (!PageSlab(page))
>    554			return NULL;
>  > 555		return kmem_cache_last_alloc(page->slab_cache, object);
>    556	}
>    557	EXPORT_SYMBOL_GPL(kmem_last_alloc);
>    558	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx