Re: [RFC PATCH 6/7] mm/slab: introduce kfree_rcu_nolock()

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

Hi Harry,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on next-20260205]
[also build test ERROR on v6.19-rc8]
[cannot apply to akpm-mm/mm-everything linus/master vbabka-slab/for-next rcu/rcu/dev v6.19-rc8 v6.19-rc7 v6.19-rc6]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Harry-Yoo/mm-slab-introduce-k-v-free_rcu-with-struct-rcu_ptr/20260206-173717
base:   next-20260205
patch link:    https://lore.kernel.org/r/20260206093410.160622-7-harry.yoo%40oracle.com
patch subject: [RFC PATCH 6/7] mm/slab: introduce kfree_rcu_nolock()
config: i386-allnoconfig (https://download.01.org/0day-ci/archive/20260207/202602071657.F7XwiIey-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260207/202602071657.F7XwiIey-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602071657.F7XwiIey-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/slab_common.c:1381:21: error: implicit declaration of function 'IRQ_WORK_INIT'; did you mean 'IRQ_WORK_VECTOR'? [-Wimplicit-function-declaration]
    1381 |         .irq_work = IRQ_WORK_INIT(defer_kfree_rcu),
         |                     ^~~~~~~~~~~~~
         |                     IRQ_WORK_VECTOR
>> mm/slab_common.c:1381:21: error: initialization of 'struct llist_node *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
   mm/slab_common.c:1381:21: note: (near initialization for 'krc.irq_work.node.llist.next')
>> mm/slab_common.c:1381:21: error: initializer element is not constant
   mm/slab_common.c:1381:21: note: (near initialization for 'krc.irq_work.node.llist.next')
   mm/slab_common.c: In function 'kvfree_call_rcu_head':
>> mm/slab_common.c:1393:25: error: implicit declaration of function 'irq_work_queue'; did you mean 'drain_workqueue'? [-Wimplicit-function-declaration]
    1393 |                         irq_work_queue(&krcp->irq_work);
         |                         ^~~~~~~~~~~~~~
         |                         drain_workqueue


vim +1381 mm/slab_common.c

  1377	
  1378	#ifndef CONFIG_KVFREE_RCU_BATCHED
  1379	static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc) = {
  1380		.llist_head = LLIST_HEAD_INIT(llist_head),
> 1381		.irq_work = IRQ_WORK_INIT(defer_kfree_rcu),
  1382	};
  1383	
  1384	void kvfree_call_rcu_head(struct rcu_head *head, void *ptr, bool allow_spin)
  1385	{
  1386		if (!allow_spin) {
  1387			struct kfree_rcu_cpu *krcp;
  1388	
  1389			guard(preempt)();
  1390	
  1391			krcp = this_cpu_ptr(&krc);
  1392			if (llist_add((struct llist_node *)head, &krcp->llist_head))
> 1393				irq_work_queue(&krcp->irq_work);
  1394			return;
  1395		}
  1396	
  1397		if (head) {
  1398			kasan_record_aux_stack(ptr);
  1399			call_rcu(head, kvfree_rcu_cb);
  1400			return;
  1401		}
  1402	
  1403		// kvfree_rcu(one_arg) call.
  1404		might_sleep();
  1405		synchronize_rcu();
  1406		kvfree(ptr);
  1407	}
  1408	EXPORT_SYMBOL_GPL(kvfree_call_rcu_head);
  1409	

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