Revision 34c96507e8f6be497c15497be05f489fb34c5880 authored by NeilBrown on 10 April 2017, 02:13:00 UTC, committed by Mike Snitzer on 26 July 2017, 19:55:44 UTC
mempool_alloc() cannot fail for GFP_NOIO allocation, so there is no
point testing for failure.

One place the code tested for failure was passing "0" as the GFP
flags.  This is most unusual and is probably meant to be GFP_NOIO,
so that is changed.

Also, allocation from ->extra_pool and ->prealloc_pool are repeated
before releasing the previous allocation.  This can deadlock if the code
is servicing a write under high memory pressure.  To avoid deadlocks,
change these to use GFP_NOWAIT and leave the error handling in place.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 parent 4218a95
Raw File
kmemleak-test.c
/*
 * 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
 */

#define pr_fmt(fmt) "kmemleak: " fmt

#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 *, kmemleak_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;

	pr_info("Kmemleak testing\n");

	/* make some orphan objects */
	pr_info("kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));
	pr_info("kmalloc(32) = %p\n", kmalloc(32, GFP_KERNEL));
	pr_info("kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));
	pr_info("kmalloc(1024) = %p\n", kmalloc(1024, GFP_KERNEL));
	pr_info("kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));
	pr_info("kmalloc(2048) = %p\n", kmalloc(2048, GFP_KERNEL));
	pr_info("kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));
	pr_info("kmalloc(4096) = %p\n", kmalloc(4096, GFP_KERNEL));
#ifndef CONFIG_MODULES
	pr_info("kmem_cache_alloc(files_cachep) = %p\n",
		kmem_cache_alloc(files_cachep, GFP_KERNEL));
	pr_info("kmem_cache_alloc(files_cachep) = %p\n",
		kmem_cache_alloc(files_cachep, GFP_KERNEL));
#endif
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("vmalloc(64) = %p\n", vmalloc(64));
	pr_info("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 = kzalloc(sizeof(*elem), GFP_KERNEL);
		pr_info("kzalloc(sizeof(*elem)) = %p\n", elem);
		if (!elem)
			return -ENOMEM;
		INIT_LIST_HEAD(&elem->list);
		list_add_tail(&elem->list, &test_list);
	}

	for_each_possible_cpu(i) {
		per_cpu(kmemleak_test_pointer, i) = kmalloc(129, GFP_KERNEL);
		pr_info("kmalloc(129) = %p\n",
			per_cpu(kmemleak_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");
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