Re: [PATCH 10/18] rcu/tree: Maintain separate array for vmalloc ptrs

[kbuild test robot]

Hi "Joel,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rcu/dev]
[also build test ERROR on rcu/rcu/next next-20200327]
[cannot apply to linus/master linux/master v5.6]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/kfree_rcu-improvements-for-rcu-dev/20200330-113719
base:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
config: mips-randconfig-a001-20200330 (attached as .config)
compiler: mips64el-linux-gcc (GCC) 5.5.0
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
        GCC_VERSION=5.5.0 make.cross ARCH=mips 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   kernel/rcu/tree.c: In function 'kfree_rcu_work':
>> kernel/rcu/tree.c:2946:4: error: implicit declaration of function 'vfree' [-Werror=implicit-function-declaration]
       vfree(bvhead->records[i]);
       ^
   cc1: some warnings being treated as errors

vim +/vfree +2946 kernel/rcu/tree.c

  2884	
  2885	/*
  2886	 * This function is invoked in workqueue context after a grace period.
  2887	 * It frees all the objects queued on ->bhead_free or ->head_free.
  2888	 */
  2889	static void kfree_rcu_work(struct work_struct *work)
  2890	{
  2891		unsigned long flags;
  2892		struct kvfree_rcu_bulk_data *bkhead, *bknext;
  2893		struct kvfree_rcu_bulk_data *bvhead, *bvnext;
  2894		struct rcu_head *head, *next;
  2895		struct kfree_rcu_cpu *krcp;
  2896		struct kfree_rcu_cpu_work *krwp;
  2897		int i;
  2898	
  2899		krwp = container_of(to_rcu_work(work),
  2900					struct kfree_rcu_cpu_work, rcu_work);
  2901	
  2902		krcp = krwp->krcp;
  2903		spin_lock_irqsave(&krcp->lock, flags);
  2904		/* Channel 1. */
  2905		bkhead = krwp->bkvhead_free[0];
  2906		krwp->bkvhead_free[0] = NULL;
  2907	
  2908		/* Channel 2. */
  2909		bvhead = krwp->bkvhead_free[1];
  2910		krwp->bkvhead_free[1] = NULL;
  2911	
  2912		/* Channel 3. */
  2913		head = krwp->head_free;
  2914		krwp->head_free = NULL;
  2915		spin_unlock_irqrestore(&krcp->lock, flags);
  2916	
  2917		/* kmalloc()/kfree() channel. */
  2918		for (; bkhead; bkhead = bknext) {
  2919			bknext = bkhead->next;
  2920	
  2921			debug_rcu_bhead_unqueue(bkhead);
  2922	
  2923			rcu_lock_acquire(&rcu_callback_map);
  2924			trace_rcu_invoke_kfree_bulk_callback(rcu_state.name,
  2925				bkhead->nr_records, bkhead->records);
  2926	
  2927			kfree_bulk(bkhead->nr_records, bkhead->records);
  2928			rcu_lock_release(&rcu_callback_map);
  2929	
  2930			if (cmpxchg(&krcp->bkvcache[0], NULL, bkhead))
  2931				free_page((unsigned long) bkhead);
  2932	
  2933			cond_resched_tasks_rcu_qs();
  2934		}
  2935	
  2936		/* vmalloc()/vfree() channel. */
  2937		for (; bvhead; bvhead = bvnext) {
  2938			bvnext = bvhead->next;
  2939	
  2940			debug_rcu_bhead_unqueue(bvhead);
  2941	
  2942			rcu_lock_acquire(&rcu_callback_map);
  2943			for (i = 0; i < bvhead->nr_records; i++) {
  2944				trace_rcu_invoke_kvfree_callback(rcu_state.name,
  2945					(struct rcu_head *) bvhead->records[i], 0);
> 2946				vfree(bvhead->records[i]);
  2947			}
  2948			rcu_lock_release(&rcu_callback_map);
  2949	
  2950			if (cmpxchg(&krcp->bkvcache[1], NULL, bvhead))
  2951				free_page((unsigned long) bvhead);
  2952	
  2953			cond_resched_tasks_rcu_qs();
  2954		}
  2955	
  2956		/*
  2957		 * This path covers emergency case only due to high
  2958		 * memory pressure also means low memory condition,
  2959		 * when we could not allocate a bulk array.
  2960		 *
  2961		 * Under that condition an object is queued to the
  2962		 * list instead.
  2963		 */
  2964		for (; head; head = next) {
  2965			unsigned long offset = (unsigned long)head->func;
  2966			void *ptr = (void *)head - offset;
  2967	
  2968			next = head->next;
  2969			debug_rcu_head_unqueue((struct rcu_head *)ptr);
  2970			rcu_lock_acquire(&rcu_callback_map);
  2971			trace_rcu_invoke_kvfree_callback(rcu_state.name, head, offset);
  2972	
  2973			if (!WARN_ON_ONCE(!__is_kvfree_rcu_offset(offset)))
  2974				kvfree(ptr);
  2975	
  2976			rcu_lock_release(&rcu_callback_map);
  2977			cond_resched_tasks_rcu_qs();
  2978		}
  2979	}
  2980	

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

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