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Subject[PATCH 13/14] 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>
---
lib/Kconfig.debug | 11 +++++
mm/Makefile | 1
mm/kmemleak-test.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 123 insertions(+), 0 deletions(-)
create mode 100644 mm/kmemleak-test.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6c9d21f..e3fb792 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -358,6 +358,17 @@ 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"
+ default n
+ 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)
diff --git a/mm/Makefile b/mm/Makefile
index cb84a02..e89acb0 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -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
diff --git a/mm/kmemleak-test.c b/mm/kmemleak-test.c
new file mode 100644
index 0000000..d5292fc
--- /dev/null
+++ b/mm/kmemleak-test.c
@@ -0,0 +1,111 @@
+/*
+ * 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");


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