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Commit 0822ee4a authored by Catalin Marinas's avatar Catalin Marinas
Browse files

kmemleak: Simple testing module for kmemleak 



This patch adds a loadable module that deliberately leaks memory. It
is used for testing various memory leaking scenarios.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 3bba00d7

lib/Kconfig.debug

+10 −0
Original line number Diff line number Diff line
@@ -358,6 +358,16 @@ config DEBUG_KMEMLEAK 
	  In order to access the kmemleak file, debugfs needs to be

	  mounted (usually at /sys/kernel/debug).



config DEBUG_KMEMLEAK_TEST

	tristate "Simple test for the kernel memory leak detector"

	depends on DEBUG_KMEMLEAK

	help

	  Say Y or M here to build a test for the kernel memory leak

	  detector. This option enables a module that explicitly leaks

	  memory.



	  If unsure, say N.



config DEBUG_PREEMPT

	bool "Debug preemptible kernel"

	depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)

mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -39,3 +39,4 @@ endif 
obj-$(CONFIG_QUICKLIST) += quicklist.o

obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o

obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o

obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o

mm/kmemleak-test.c

0 → 100644
+111 −0
Original line number Diff line number Diff line 
/*

 * mm/kmemleak-test.c

 *

 * Copyright (C) 2008 ARM Limited

 * Written by Catalin Marinas <catalin.marinas@arm.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

 */



#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/list.h>

#include <linux/percpu.h>

#include <linux/fdtable.h>



#include <linux/kmemleak.h>



struct test_node {

	long header[25];

	struct list_head list;

	long footer[25];

};



static LIST_HEAD(test_list);

static DEFINE_PER_CPU(void *, test_pointer);



/*

 * Some very simple testing. This function needs to be extended for

 * proper testing.

 */

static int __init kmemleak_test_init(void)

{

	struct test_node *elem;

	int i;



	printk(KERN_INFO "Kmemleak testing\n");



	/* make some orphan objects */

	pr_info("kmemleak: kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));

	pr_info("kmemleak: kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));

#ifndef CONFIG_MODULES

	pr_info("kmemleak: kmem_cache_alloc(files_cachep) = %p\n",

		kmem_cache_alloc(files_cachep, GFP_KERNEL));

	pr_info("kmemleak: kmem_cache_alloc(files_cachep) = %p\n",

		kmem_cache_alloc(files_cachep, GFP_KERNEL));

#endif

	pr_info("kmemleak: vmalloc(64) = %p\n", vmalloc(64));

	pr_info("kmemleak: vmalloc(64) = %p\n", vmalloc(64));

	pr_info("kmemleak: vmalloc(64) = %p\n", vmalloc(64));

	pr_info("kmemleak: vmalloc(64) = %p\n", vmalloc(64));

	pr_info("kmemleak: vmalloc(64) = %p\n", vmalloc(64));



	/*

	 * Add elements to a list. They should only appear as orphan

	 * after the module is removed.

	 */

	for (i = 0; i < 10; i++) {

		elem = kmalloc(sizeof(*elem), GFP_KERNEL);

		pr_info("kmemleak: kmalloc(sizeof(*elem)) = %p\n", elem);

		if (!elem)

			return -ENOMEM;

		memset(elem, 0, sizeof(*elem));

		INIT_LIST_HEAD(&elem->list);



		list_add_tail(&elem->list, &test_list);

	}



	for_each_possible_cpu(i) {

		per_cpu(test_pointer, i) = kmalloc(129, GFP_KERNEL);

		pr_info("kmemleak: kmalloc(129) = %p\n",

			per_cpu(test_pointer, i));

	}



	return 0;

}

module_init(kmemleak_test_init);



static void __exit kmemleak_test_exit(void)

{

	struct test_node *elem, *tmp;



	/*

	 * Remove the list elements without actually freeing the

	 * memory.

	 */

	list_for_each_entry_safe(elem, tmp, &test_list, list)

		list_del(&elem->list);

}

module_exit(kmemleak_test_exit);



MODULE_LICENSE("GPL");