• K
    memcg: initialize kmem-cache destroying work earlier · 15cf17d2
    Konstantin Khlebnikov 提交于
    Fix a warning from lockdep caused by calling cancel_work_sync() for
    uninitialized struct work.  This path has been triggered by destructon
    kmem-cache hierarchy via destroying its root kmem-cache.
    
      cache ffff88003c072d80
      obj ffff88003b410000 cache ffff88003c072d80
      obj ffff88003b924000 cache ffff88003c20bd40
      INFO: trying to register non-static key.
      the code is fine but needs lockdep annotation.
      turning off the locking correctness validator.
      Pid: 2825, comm: insmod Tainted: G           O 3.9.0-rc1-next-20130307+ #611
      Call Trace:
        __lock_acquire+0x16a2/0x1cb0
        lock_acquire+0x8a/0x120
        flush_work+0x38/0x2a0
        __cancel_work_timer+0x89/0xf0
        cancel_work_sync+0xb/0x10
        kmem_cache_destroy_memcg_children+0x81/0xb0
        kmem_cache_destroy+0xf/0xe0
        init_module+0xcb/0x1000 [kmem_test]
        do_one_initcall+0x11a/0x170
        load_module+0x19b0/0x2320
        SyS_init_module+0xc6/0xf0
        system_call_fastpath+0x16/0x1b
    
    Example module to demonstrate:
    
      #include <linux/module.h>
      #include <linux/slab.h>
      #include <linux/mm.h>
      #include <linux/workqueue.h>
    
      int __init mod_init(void)
      {
      	int size = 256;
      	struct kmem_cache *cache;
      	void *obj;
      	struct page *page;
    
      	cache = kmem_cache_create("kmem_cache_test", size, size, 0, NULL);
      	if (!cache)
      		return -ENOMEM;
    
      	printk("cache %p\n", cache);
    
      	obj = kmem_cache_alloc(cache, GFP_KERNEL);
      	if (obj) {
      		page = virt_to_head_page(obj);
      		printk("obj %p cache %p\n", obj, page->slab_cache);
      		kmem_cache_free(cache, obj);
      	}
    
      	flush_scheduled_work();
    
      	obj = kmem_cache_alloc(cache, GFP_KERNEL);
      	if (obj) {
      		page = virt_to_head_page(obj);
      		printk("obj %p cache %p\n", obj, page->slab_cache);
      		kmem_cache_free(cache, obj);
      	}
    
      	kmem_cache_destroy(cache);
    
      	return -EBUSY;
      }
    
      module_init(mod_init);
      MODULE_LICENSE("GPL");
    Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
    Cc: Glauber Costa <glommer@parallels.com>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    15cf17d2
memcontrol.c 180.4 KB