Revision 4528fd0595847c2078b59f24800e751c2d6b7e41 authored by Li Zefan on 02 February 2010, 21:44:10 UTC, committed by Linus Torvalds on 03 February 2010, 02:11:22 UTC
In cgroup_create(), if alloc_css_id() returns failure, the errno is not
propagated to userspace, so mkdir will fail silently.

To trigger this bug, we mount blkio (or memory subsystem), and create more
then 65534 cgroups.  (The number of cgroups is limited to 65535 if a
subsystem has use_id == 1)

 # mount -t cgroup -o blkio xxx /mnt
 # for ((i = 0; i < 65534; i++)); do mkdir /mnt/$i; done
 # mkdir /mnt/65534
 (should return ENOSPC)
 #

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent ef2b9b0
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/module.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;
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
		"Section %d Node %d Zone %d Flags %d\n",
		SECTIONS_WIDTH,
		NODES_WIDTH,
		ZONES_WIDTH,
		NR_PAGEFLAGS);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
		"Section %d Node %d Zone %d\n",
		SECTIONS_SHIFT,
		NODES_SHIFT,
		ZONES_SHIFT);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_offsets",
		"Section %lu Node %lu Zone %lu\n",
		(unsigned long)SECTIONS_PGSHIFT,
		(unsigned long)NODES_PGSHIFT,
		(unsigned long)ZONES_PGSHIFT);
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_zoneid",
		"Zone ID: %lu -> %lu\n",
		(unsigned long)ZONEID_PGOFF,
		(unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT));
	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_usage",
		"location: %d -> %d unused %d -> %d flags %d -> %d\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

	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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