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    Subject[PATCH 14/15] kmemleak: Simple testing module for kmemleak
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    This patch adds a loadable module that deliberately leaks memory. It
    is used for testing various memory leaking scenarios.

    Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    ---
    lib/Kconfig.debug | 11 +++++
    mm/Makefile | 1
    mm/memleak-test.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 121 insertions(+), 0 deletions(-)
    create mode 100644 mm/memleak-test.c

    diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
    index 72cde77..205c1da 100644
    --- a/lib/Kconfig.debug
    +++ b/lib/Kconfig.debug
    @@ -313,6 +313,17 @@ config DEBUG_MEMLEAK
    In order to access the memleak file, debugfs needs to be
    mounted (usually at /sys/kernel/debug).

    +config DEBUG_MEMLEAK_TEST
    + tristate "Test the kernel memory leak detector"
    + default n
    + depends on DEBUG_MEMLEAK
    + 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_KEEP_INIT
    bool "Do not free the __init code/data"
    default n
    diff --git a/mm/Makefile b/mm/Makefile
    index 3e43536..deb5935 100644
    --- a/mm/Makefile
    +++ b/mm/Makefile
    @@ -35,3 +35,4 @@ obj-$(CONFIG_SMP) += allocpercpu.o
    obj-$(CONFIG_QUICKLIST) += quicklist.o
    obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
    obj-$(CONFIG_DEBUG_MEMLEAK) += memleak.o
    +obj-$(CONFIG_DEBUG_MEMLEAK_TEST) += memleak-test.o
    diff --git a/mm/memleak-test.c b/mm/memleak-test.c
    new file mode 100644
    index 0000000..c7315af
    --- /dev/null
    +++ b/mm/memleak-test.c
    @@ -0,0 +1,109 @@
    +/*
    + * mm/memleak-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/memleak.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 memleak_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(memleak_test_init);
    +
    +static void __exit memleak_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(memleak_test_exit);
    +
    +MODULE_LICENSE("GPL");


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