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

[Uladzislau Rezki]

Hello, Joel.

Sent out the patch fixing build error.

--
Vlad Rezki

> 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