Revision 15cf17d26e08ee95c2e392a3a71f55d32e99e971 authored by Konstantin Khlebnikov on 08 March 2013, 20:43:36 UTC, committed by Linus Torvalds on 08 March 2013, 23:05:34 UTC
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: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 755727b
Raw File
mm_init.c
/*
 * mm_init.c - Memory initialisation verification and debugging
 *
 * Copyright 2008 IBM Corporation, 2008
 * Author Mel Gorman <mel@csn.ul.ie>
 *
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/export.h>
#include "internal.h"

#ifdef CONFIG_DEBUG_MEMORY_INIT
int mminit_loglevel;

#ifndef SECTIONS_SHIFT
#define SECTIONS_SHIFT	0
#endif

/* The zonelists are simply reported, validation is manual. */
void mminit_verify_zonelist(void)
{
	int nid;

	if (mminit_loglevel < MMINIT_VERIFY)
		return;

	for_each_online_node(nid) {
		pg_data_t *pgdat = NODE_DATA(nid);
		struct zone *zone;
		struct zoneref *z;
		struct zonelist *zonelist;
		int i, listid, zoneid;

		BUG_ON(MAX_ZONELISTS > 2);
		for (i = 0; i < MAX_ZONELISTS * MAX_NR_ZONES; i++) {

			/* Identify the zone and nodelist */
			zoneid = i % MAX_NR_ZONES;
			listid = i / MAX_NR_ZONES;
			zonelist = &pgdat->node_zonelists[listid];
			zone = &pgdat->node_zones[zoneid];
			if (!populated_zone(zone))
				continue;

			/* Print information about the zonelist */
			printk(KERN_DEBUG "mminit::zonelist %s %d:%s = ",
				listid > 0 ? "thisnode" : "general", nid,
				zone->name);

			/* Iterate the zonelist */
			for_each_zone_zonelist(zone, z, zonelist, zoneid) {
#ifdef CONFIG_NUMA
				printk(KERN_CONT "%d:%s ",
					zone->node, zone->name);
#else
				printk(KERN_CONT "0:%s ", zone->name);
#endif /* CONFIG_NUMA */
			}
			printk(KERN_CONT "\n");
		}
	}
}

void __init mminit_verify_pageflags_layout(void)
{
	int shift, width;
	unsigned long or_mask, add_mask;

	shift = 8 * sizeof(unsigned long);
	width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH - LAST_NID_SHIFT;
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
		"Section %d Node %d Zone %d Lastnid %d Flags %d\n",
		SECTIONS_WIDTH,
		NODES_WIDTH,
		ZONES_WIDTH,
		LAST_NID_WIDTH,
		NR_PAGEFLAGS);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
		"Section %d Node %d Zone %d Lastnid %d\n",
		SECTIONS_SHIFT,
		NODES_SHIFT,
		ZONES_SHIFT,
		LAST_NID_SHIFT);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_pgshifts",
		"Section %lu Node %lu Zone %lu Lastnid %lu\n",
		(unsigned long)SECTIONS_PGSHIFT,
		(unsigned long)NODES_PGSHIFT,
		(unsigned long)ZONES_PGSHIFT,
		(unsigned long)LAST_NID_PGSHIFT);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodezoneid",
		"Node/Zone ID: %lu -> %lu\n",
		(unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT),
		(unsigned long)ZONEID_PGOFF);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_usage",
		"location: %d -> %d layout %d -> %d unused %d -> %d page-flags\n",
		shift, width, width, NR_PAGEFLAGS, NR_PAGEFLAGS, 0);
#ifdef NODE_NOT_IN_PAGE_FLAGS
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
		"Node not in page flags");
#endif
#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
		"Last nid not in page flags");
#endif

	if (SECTIONS_WIDTH) {
		shift -= SECTIONS_WIDTH;
		BUG_ON(shift != SECTIONS_PGSHIFT);
	}
	if (NODES_WIDTH) {
		shift -= NODES_WIDTH;
		BUG_ON(shift != NODES_PGSHIFT);
	}
	if (ZONES_WIDTH) {
		shift -= ZONES_WIDTH;
		BUG_ON(shift != ZONES_PGSHIFT);
	}

	/* Check for bitmask overlaps */
	or_mask = (ZONES_MASK << ZONES_PGSHIFT) |
			(NODES_MASK << NODES_PGSHIFT) |
			(SECTIONS_MASK << SECTIONS_PGSHIFT);
	add_mask = (ZONES_MASK << ZONES_PGSHIFT) +
			(NODES_MASK << NODES_PGSHIFT) +
			(SECTIONS_MASK << SECTIONS_PGSHIFT);
	BUG_ON(or_mask != add_mask);
}

void __meminit mminit_verify_page_links(struct page *page, enum zone_type zone,
			unsigned long nid, unsigned long pfn)
{
	BUG_ON(page_to_nid(page) != nid);
	BUG_ON(page_zonenum(page) != zone);
	BUG_ON(page_to_pfn(page) != pfn);
}

static __init int set_mminit_loglevel(char *str)
{
	get_option(&str, &mminit_loglevel);
	return 0;
}
early_param("mminit_loglevel", set_mminit_loglevel);
#endif /* CONFIG_DEBUG_MEMORY_INIT */

struct kobject *mm_kobj;
EXPORT_SYMBOL_GPL(mm_kobj);

static int __init mm_sysfs_init(void)
{
	mm_kobj = kobject_create_and_add("mm", kernel_kobj);
	if (!mm_kobj)
		return -ENOMEM;

	return 0;
}

__initcall(mm_sysfs_init);
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