Merge branch 'for-linus' of git://linux-arm.org/linux-2.6

* 'for-linus' of git://linux-arm.org/linux-2.6:
  kmemleak: Add the corresponding MAINTAINERS entry
  kmemleak: Simple testing module for kmemleak
  kmemleak: Enable the building of the memory leak detector
  kmemleak: Remove some of the kmemleak false positives
  kmemleak: Add modules support
  kmemleak: Add kmemleak_alloc callback from alloc_large_system_hash
  kmemleak: Add the vmalloc memory allocation/freeing hooks
  kmemleak: Add the slub memory allocation/freeing hooks
  kmemleak: Add the slob memory allocation/freeing hooks
  kmemleak: Add the slab memory allocation/freeing hooks
  kmemleak: Add documentation on the memory leak detector
  kmemleak: Add the base support

Manual conflict resolution (with the slab/earlyboot changes) in:
	drivers/char/vt.c
	init/main.c
	mm/slab.c

19 files changed, 2043 insertions, 7 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 72d3bf08d79..7bcdebffdab 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1083,6 +1083,10 @@ and is between 256 and 4096 characters. It is defined in the file
 			Configure the RouterBoard 532 series on-chip
 			Ethernet adapter MAC address.
 
+	kmemleak=	[KNL] Boot-time kmemleak enable/disable
+			Valid arguments: on, off
+			Default: on
+
 	kstack=N	[X86] Print N words from the kernel stack
 			in oops dumps.
 
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
new file mode 100644
index 00000000000..0112da3b9ab
--- /dev/null
+++ b/Documentation/kmemleak.txt
@@ -0,0 +1,142 @@
+Kernel Memory Leak Detector
+===========================
+
+Introduction
+------------
+
+Kmemleak provides a way of detecting possible kernel memory leaks in a
+way similar to a tracing garbage collector
+(http://en.wikipedia.org/wiki/Garbage_collection_%28computer_science%29#Tracing_garbage_collectors),
+with the difference that the orphan objects are not freed but only
+reported via /sys/kernel/debug/kmemleak. A similar method is used by the
+Valgrind tool (memcheck --leak-check) to detect the memory leaks in
+user-space applications.
+
+Usage
+-----
+
+CONFIG_DEBUG_KMEMLEAK in "Kernel hacking" has to be enabled. A kernel
+thread scans the memory every 10 minutes (by default) and prints any new
+unreferenced objects found. To trigger an intermediate scan and display
+all the possible memory leaks:
+
+  # mount -t debugfs nodev /sys/kernel/debug/
+  # cat /sys/kernel/debug/kmemleak
+
+Note that the orphan objects are listed in the order they were allocated
+and one object at the beginning of the list may cause other subsequent
+objects to be reported as orphan.
+
+Memory scanning parameters can be modified at run-time by writing to the
+/sys/kernel/debug/kmemleak file. The following parameters are supported:
+
+  off		- disable kmemleak (irreversible)
+  stack=on	- enable the task stacks scanning
+  stack=off	- disable the tasks stacks scanning
+  scan=on	- start the automatic memory scanning thread
+  scan=off	- stop the automatic memory scanning thread
+  scan=<secs>	- set the automatic memory scanning period in seconds (0
+		  to disable it)
+
+Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on
+the kernel command line.
+
+Basic Algorithm
+---------------
+
+The memory allocations via kmalloc, vmalloc, kmem_cache_alloc and
+friends are traced and the pointers, together with additional
+information like size and stack trace, are stored in a prio search tree.
+The corresponding freeing function calls are tracked and the pointers
+removed from the kmemleak data structures.
+
+An allocated block of memory is considered orphan if no pointer to its
+start address or to any location inside the block can be found by
+scanning the memory (including saved registers). This means that there
+might be no way for the kernel to pass the address of the allocated
+block to a freeing function and therefore the block is considered a
+memory leak.
+
+The scanning algorithm steps:
+
+  1. mark all objects as white (remaining white objects will later be
+     considered orphan)
+  2. scan the memory starting with the data section and stacks, checking
+     the values against the addresses stored in the prio search tree. If
+     a pointer to a white object is found, the object is added to the
+     gray list
+  3. scan the gray objects for matching addresses (some white objects
+     can become gray and added at the end of the gray list) until the
+     gray set is finished
+  4. the remaining white objects are considered orphan and reported via
+     /sys/kernel/debug/kmemleak
+
+Some allocated memory blocks have pointers stored in the kernel's
+internal data structures and they cannot be detected as orphans. To
+avoid this, kmemleak can also store the number of values pointing to an
+address inside the block address range that need to be found so that the
+block is not considered a leak. One example is __vmalloc().
+
+Kmemleak API
+------------
+
+See the include/linux/kmemleak.h header for the functions prototype.
+
+kmemleak_init		 - initialize kmemleak
+kmemleak_alloc		 - notify of a memory block allocation
+kmemleak_free		 - notify of a memory block freeing
+kmemleak_not_leak	 - mark an object as not a leak
+kmemleak_ignore		 - do not scan or report an object as leak
+kmemleak_scan_area	 - add scan areas inside a memory block
+kmemleak_no_scan	 - do not scan a memory block
+kmemleak_erase		 - erase an old value in a pointer variable
+kmemleak_alloc_recursive - as kmemleak_alloc but checks the recursiveness
+kmemleak_free_recursive	 - as kmemleak_free but checks the recursiveness
+
+Dealing with false positives/negatives
+--------------------------------------
+
+The false negatives are real memory leaks (orphan objects) but not
+reported by kmemleak because values found during the memory scanning
+point to such objects. To reduce the number of false negatives, kmemleak
+provides the kmemleak_ignore, kmemleak_scan_area, kmemleak_no_scan and
+kmemleak_erase functions (see above). The task stacks also increase the
+amount of false negatives and their scanning is not enabled by default.
+
+The false positives are objects wrongly reported as being memory leaks
+(orphan). For objects known not to be leaks, kmemleak provides the
+kmemleak_not_leak function. The kmemleak_ignore could also be used if
+the memory block is known not to contain other pointers and it will no
+longer be scanned.
+
+Some of the reported leaks are only transient, especially on SMP
+systems, because of pointers temporarily stored in CPU registers or
+stacks. Kmemleak defines MSECS_MIN_AGE (defaulting to 1000) representing
+the minimum age of an object to be reported as a memory leak.
+
+Limitations and Drawbacks
+-------------------------
+
+The main drawback is the reduced performance of memory allocation and
+freeing. To avoid other penalties, the memory scanning is only performed
+when the /sys/kernel/debug/kmemleak file is read. Anyway, this tool is
+intended for debugging purposes where the performance might not be the
+most important requirement.
+
+To keep the algorithm simple, kmemleak scans for values pointing to any
+address inside a block's address range. This may lead to an increased
+number of false negatives. However, it is likely that a real memory leak
+will eventually become visible.
+
+Another source of false negatives is the data stored in non-pointer
+values. In a future version, kmemleak could only scan the pointer
+members in the allocated structures. This feature would solve many of
+the false negative cases described above.
+
+The tool can report false positives. These are cases where an allocated
+block doesn't need to be freed (some cases in the init_call functions),
+the pointer is calculated by other methods than the usual container_of
+macro or the pointer is stored in a location not scanned by kmemleak.
+
+Page allocations and ioremap are not tracked. Only the ARM and x86
+architectures are currently supported.
diff --git a/MAINTAINERS b/MAINTAINERS
index 70f961d43d9..1a0084e22cf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3370,6 +3370,12 @@ F:	Documentation/trace/kmemtrace.txt
 F:	include/trace/kmemtrace.h
 F:	kernel/trace/kmemtrace.c
 
+KMEMLEAK
+P:	Catalin Marinas
+M:	catalin.marinas@arm.com
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+
 KPROBES
 P:	Ananth N Mavinakayanahalli
 M:	ananth@in.ibm.com
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index c796a86ab7f..de9ebee8657 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -103,6 +103,7 @@
 #include <linux/io.h>
 #include <asm/system.h>
 #include <linux/uaccess.h>
+#include <linux/kmemleak.h>
 
 #define MAX_NR_CON_DRIVER 16
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2dfc6cdcebb..931f6b8c4b2 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -25,6 +25,7 @@
 #include <linux/uio.h>
 #include <linux/namei.h>
 #include <linux/log2.h>
+#include <linux/kmemleak.h>
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -492,6 +493,11 @@ void __init bdev_cache_init(void)
 	bd_mnt = kern_mount(&bd_type);
 	if (IS_ERR(bd_mnt))
 		panic("Cannot create bdev pseudo-fs");
+	/*
+	 * This vfsmount structure is only used to obtain the
+	 * blockdev_superblock, so tell kmemleak not to report it.
+	 */
+	kmemleak_not_leak(bd_mnt);
 	blockdev_superblock = bd_mnt->mnt_sb;	/* For writeback */
 }
 
diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
new file mode 100644
index 00000000000..7796aed6cdd
--- /dev/null
+++ b/include/linux/kmemleak.h
@@ -0,0 +1,96 @@
+/*
+ * include/linux/kmemleak.h
+ *
+ * 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
+ */
+
+#ifndef __KMEMLEAK_H
+#define __KMEMLEAK_H
+
+#ifdef CONFIG_DEBUG_KMEMLEAK
+
+extern void kmemleak_init(void);
+extern void kmemleak_alloc(const void *ptr, size_t size, int min_count,
+			   gfp_t gfp);
+extern void kmemleak_free(const void *ptr);
+extern void kmemleak_padding(const void *ptr, unsigned long offset,
+			     size_t size);
+extern void kmemleak_not_leak(const void *ptr);
+extern void kmemleak_ignore(const void *ptr);
+extern void kmemleak_scan_area(const void *ptr, unsigned long offset,
+			       size_t length, gfp_t gfp);
+extern void kmemleak_no_scan(const void *ptr);
+
+static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
+					    int min_count, unsigned long flags,
+					    gfp_t gfp)
+{
+	if (!(flags & SLAB_NOLEAKTRACE))
+		kmemleak_alloc(ptr, size, min_count, gfp);
+}
+
+static inline void kmemleak_free_recursive(const void *ptr, unsigned long flags)
+{
+	if (!(flags & SLAB_NOLEAKTRACE))
+		kmemleak_free(ptr);
+}
+
+static inline void kmemleak_erase(void **ptr)
+{
+	*ptr = NULL;
+}
+
+#else
+
+static inline void kmemleak_init(void)
+{
+}
+static inline void kmemleak_alloc(const void *ptr, size_t size, int min_count,
+				  gfp_t gfp)
+{
+}
+static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
+					    int min_count, unsigned long flags,
+					    gfp_t gfp)
+{
+}
+static inline void kmemleak_free(const void *ptr)
+{
+}
+static inline void kmemleak_free_recursive(const void *ptr, unsigned long flags)
+{
+}
+static inline void kmemleak_not_leak(const void *ptr)
+{
+}
+static inline void kmemleak_ignore(const void *ptr)
+{
+}
+static inline void kmemleak_scan_area(const void *ptr, unsigned long offset,
+				      size_t length, gfp_t gfp)
+{
+}
+static inline void kmemleak_erase(void **ptr)
+{
+}
+static inline void kmemleak_no_scan(const void *ptr)
+{
+}
+
+#endif	/* CONFIG_DEBUG_KMEMLEAK */
+
+#endif	/* __KMEMLEAK_H */
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 1581ff235c7..26fd9d12f05 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -86,7 +86,12 @@ struct percpu_data {
 	void *ptrs[1];
 };
 
+/* pointer disguising messes up the kmemleak objects tracking */
+#ifndef CONFIG_DEBUG_KMEMLEAK
 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
+#else
+#define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
+#endif
 
 #define per_cpu_ptr(ptr, cpu)						\
 ({									\
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 24c5602bee9..48803064ced 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -62,6 +62,8 @@
 # define SLAB_DEBUG_OBJECTS	0x00000000UL
 #endif
 
+#define SLAB_NOLEAKTRACE	0x00800000UL	/* Avoid kmemleak tracing */
+
 /* The following flags affect the page allocator grouping pages by mobility */
 #define SLAB_RECLAIM_ACCOUNT	0x00020000UL		/* Objects are reclaimable */
 #define SLAB_TEMPORARY		SLAB_RECLAIM_ACCOUNT	/* Objects are short-lived */
diff --git a/init/main.c b/init/main.c
index 7917695bf71..5616661eac0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -56,6 +56,7 @@
 #include <linux/debug_locks.h>
 #include <linux/debugobjects.h>
 #include <linux/lockdep.h>
+#include <linux/kmemleak.h>
 #include <linux/pid_namespace.h>
 #include <linux/device.h>
 #include <linux/kthread.h>
@@ -621,6 +622,7 @@ asmlinkage void __init start_kernel(void)
 	/* init some links before init_ISA_irqs() */
 	early_irq_init();
 	init_IRQ();
+	prio_tree_init();
 	init_timers();
 	hrtimers_init();
 	softirq_init();
@@ -667,6 +669,7 @@ asmlinkage void __init start_kernel(void)
 	enable_debug_pagealloc();
 	cpu_hotplug_init();
 	kmemtrace_init();
+	kmemleak_init();
 	debug_objects_mem_init();
 	idr_init_cache();
 	setup_per_cpu_pageset();
@@ -676,7 +679,6 @@ asmlinkage void __init start_kernel(void)
 	calibrate_delay();
 	pidmap_init();
 	pgtable_cache_init();
-	prio_tree_init();
 	anon_vma_init();
 #ifdef CONFIG_X86
 	if (efi_enabled)
diff --git a/kernel/module.c b/kernel/module.c
index 278e9b6762b..35f7de00bf0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -53,6 +53,7 @@
 #include <linux/ftrace.h>
 #include <linux/async.h>
 #include <linux/percpu.h>
+#include <linux/kmemleak.h>
 
 #if 0
 #define DEBUGP printk
@@ -433,6 +434,7 @@ static void *percpu_modalloc(unsigned long size, unsigned long align,
 	unsigned long extra;
 	unsigned int i;
 	void *ptr;
+	int cpu;
 
 	if (align > PAGE_SIZE) {
 		printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
@@ -462,6 +464,11 @@ static void *percpu_modalloc(unsigned long size, unsigned long align,
 			if (!split_block(i, size))
 				return NULL;
 
+		/* add the per-cpu scanning areas */
+		for_each_possible_cpu(cpu)
+			kmemleak_alloc(ptr + per_cpu_offset(cpu), size, 0,
+				       GFP_KERNEL);
+
 		/* Mark allocated */
 		pcpu_size[i] = -pcpu_size[i];
 		return ptr;
@@ -476,6 +483,7 @@ static void percpu_modfree(void *freeme)
 {
 	unsigned int i;
 	void *ptr = __per_cpu_start + block_size(pcpu_size[0]);
+	int cpu;
 
 	/* First entry is core kernel percpu data. */
 	for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) {
@@ -487,6 +495,10 @@ static void percpu_modfree(void *freeme)
 	BUG();
 
  free:
+	/* remove the per-cpu scanning areas */
+	for_each_possible_cpu(cpu)
+		kmemleak_free(freeme + per_cpu_offset(cpu));
+
 	/* Merge with previous? */
 	if (pcpu_size[i-1] >= 0) {
 		pcpu_size[i-1] += pcpu_size[i];
@@ -1879,6 +1891,36 @@ static void *module_alloc_update_bounds(unsigned long size)
 	return ret;
 }
 
+#ifdef CONFIG_DEBUG_KMEMLEAK
+static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
+				 Elf_Shdr *sechdrs, char *secstrings)
+{
+	unsigned int i;
+
+	/* only scan the sections containing data */
+	kmemleak_scan_area(mod->module_core, (unsigned long)mod -
+			   (unsigned long)mod->module_core,
+			   sizeof(struct module), GFP_KERNEL);
+
+	for (i = 1; i < hdr->e_shnum; i++) {
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+		if (strncmp(secstrings + sechdrs[i].sh_name, ".data", 5) != 0
+		    && strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0)
+			continue;
+
+		kmemleak_scan_area(mod->module_core, sechdrs[i].sh_addr -
+				   (unsigned long)mod->module_core,
+				   sechdrs[i].sh_size, GFP_KERNEL);
+	}
+}
+#else
+static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
+					Elf_Shdr *sechdrs, char *secstrings)
+{
+}
+#endif
+
 /* Allocate and load the module: note that size of section 0 is always
    zero, and we rely on this for optional sections. */
 static noinline struct module *load_module(void __user *umod,
@@ -2049,6 +2091,12 @@ static noinline struct module *load_module(void __user *umod,
 
 	/* Do the allocs. */
 	ptr = module_alloc_update_bounds(mod->core_size);
+	/*
+	 * The pointer to this block is stored in the module structure
+	 * which is inside the block. Just mark it as not being a
+	 * leak.
+	 */
+	kmemleak_not_leak(ptr);
 	if (!ptr) {
 		err = -ENOMEM;
 		goto free_percpu;
@@ -2057,6 +2105,13 @@ static noinline struct module *load_module(void __user *umod,
 	mod->module_core = ptr;
 
 	ptr = module_alloc_update_bounds(mod->init_size);
+	/*
+	 * The pointer to this block is stored in the module structure
+	 * which is inside the block. This block doesn't need to be
+	 * scanned as it contains data and code that will be freed
+	 * after the module is initialized.
+	 */
+	kmemleak_ignore(ptr);
 	if (!ptr && mod->init_size) {
 		err = -ENOMEM;
 		goto free_core;
@@ -2087,6 +2142,7 @@ static noinline struct module *load_module(void __user *umod,
 	}
 	/* Module has been moved. */
 	mod = (void *)sechdrs[modindex].sh_addr;
+	kmemleak_load_module(mod, hdr, sechdrs, secstrings);
 
 #if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
 	mod->refptr = percpu_modalloc(sizeof(local_t), __alignof__(local_t),
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6cdcf38f2da..116a35051be 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -336,6 +336,38 @@ config SLUB_STATS
 	  out which slabs are relevant to a particular load.
 	  Try running: slabinfo -DA
 
+config DEBUG_KMEMLEAK
+	bool "Kernel memory leak detector"
+	depends on DEBUG_KERNEL && EXPERIMENTAL && (X86 || ARM) && \
+		!MEMORY_HOTPLUG
+	select DEBUG_SLAB if SLAB
+	select SLUB_DEBUG if SLUB
+	select DEBUG_FS if SYSFS
+	select STACKTRACE if STACKTRACE_SUPPORT
+	select KALLSYMS
+	help
+	  Say Y here if you want to enable the memory leak
+	  detector. The memory allocation/freeing is traced in a way
+	  similar to the Boehm's conservative garbage collector, the
+	  difference being that the orphan objects are not freed but
+	  only shown in /sys/kernel/debug/kmemleak. Enabling this
+	  feature will introduce an overhead to memory
+	  allocations. See Documentation/kmemleak.txt for more
+	  details.
+
+	  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)
diff --git a/mm/Makefile b/mm/Makefile
index ec73c68b601..e89acb090b4 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -38,3 +38,5 @@ obj-$(CONFIG_SMP) += allocpercpu.o
 endif
 obj-$(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 00000000000..d5292fc6f52
--- /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");
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
new file mode 100644
index 00000000000..58ec86c9e58
--- /dev/null
+++ b/mm/kmemleak.c
@@ -0,0 +1,1498 @@
+/*
+ * mm/kmemleak.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
+ *
+ *
+ * For more information on the algorithm and kmemleak usage, please see
+ * Documentation/kmemleak.txt.
+ *
+ * Notes on locking
+ * ----------------
+ *
+ * The following locks and mutexes are used by kmemleak:
+ *
+ * - kmemleak_lock (rwlock): protects the object_list modifications and
+ *   accesses to the object_tree_root. The object_list is the main list
+ *   holding the metadata (struct kmemleak_object) for the allocated memory
+ *   blocks. The object_tree_root is a priority search tree used to look-up
+ *   metadata based on a pointer to the corresponding memory block.  The
+ *   kmemleak_object structures are added to the object_list and
+ *   object_tree_root in the create_object() function called from the
+ *   kmemleak_alloc() callback and removed in delete_object() called from the
+ *   kmemleak_free() callback
+ * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
+ *   the metadata (e.g. count) are protected by this lock. Note that some
+ *   members of this structure may be protected by other means (atomic or
+ *   kmemleak_lock). This lock is also held when scanning the corresponding
+ *   memory block to avoid the kernel freeing it via the kmemleak_free()
+ *   callback. This is less heavyweight than holding a global lock like
+ *   kmemleak_lock during scanning
+ * - scan_mutex (mutex): ensures that only one thread may scan the memory for
+ *   unreferenced objects at a time. The gray_list contains the objects which
+ *   are already referenced or marked as false positives and need to be
+ *   scanned. This list is only modified during a scanning episode when the
+ *   scan_mutex is held. At the end of a scan, the gray_list is always empty.
+ *   Note that the kmemleak_object.use_count is incremented when an object is
+ *   added to the gray_list and therefore cannot be freed
+ * - kmemleak_mutex (mutex): prevents multiple users of the "kmemleak" debugfs
+ *   file together with modifications to the memory scanning parameters
+ *   including the scan_thread pointer
+ *
+ * The kmemleak_object structures have a use_count incremented or decremented
+ * using the get_object()/put_object() functions. When the use_count becomes
+ * 0, this count can no longer be incremented and put_object() schedules the
+ * kmemleak_object freeing via an RCU callback. All calls to the get_object()
+ * function must be protected by rcu_read_lock() to avoid accessing a freed
+ * structure.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/prio_tree.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/cpumask.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/rcupdate.h>
+#include <linux/stacktrace.h>
+#include <linux/cache.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/mmzone.h>
+#include <linux/slab.h>
+#include <linux/thread_info.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/string.h>
+#include <linux/nodemask.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+#include <asm/processor.h>
+#include <asm/atomic.h>
+
+#include <linux/kmemleak.h>
+
+/*
+ * Kmemleak configuration and common defines.
+ */
+#define MAX_TRACE		16	/* stack trace length */
+#define REPORTS_NR		50	/* maximum number of reported leaks */
+#define MSECS_MIN_AGE		5000	/* minimum object age for reporting */
+#define MSECS_SCAN_YIELD	10	/* CPU yielding period */
+#define SECS_FIRST_SCAN		60	/* delay before the first scan */
+#define SECS_SCAN_WAIT		600	/* subsequent auto scanning delay */
+
+#define BYTES_PER_POINTER	sizeof(void *)
+
+/* scanning area inside a memory block */
+struct kmemleak_scan_area {
+	struct hlist_node node;
+	unsigned long offset;
+	size_t length;
+};
+
+/*
+ * Structure holding the metadata for each allocated memory block.
+ * Modifications to such objects should be made while holding the
+ * object->lock. Insertions or deletions from object_list, gray_list or
+ * tree_node are already protected by the corresponding locks or mutex (see
+ * the notes on locking above). These objects are reference-counted
+ * (use_count) and freed using the RCU mechanism.
+ */
+struct kmemleak_object {
+	spinlock_t lock;
+	unsigned long flags;		/* object status flags */
+	struct list_head object_list;
+	struct list_head gray_list;
+	struct prio_tree_node tree_node;
+	struct rcu_head rcu;		/* object_list lockless traversal */
+	/* object usage count; object freed when use_count == 0 */
+	atomic_t use_count;
+	unsigned long pointer;
+	size_t size;
+	/* minimum number of a pointers found before it is considered leak */
+	int min_count;
+	/* the total number of pointers found pointing to this object */
+	int count;
+	/* memory ranges to be scanned inside an object (empty for all) */
+	struct hlist_head area_list;
+	unsigned long trace[MAX_TRACE];
+	unsigned int trace_len;
+	unsigned long jiffies;		/* creation timestamp */
+	pid_t pid;			/* pid of the current task */
+	char comm[TASK_COMM_LEN];	/* executable name */
+};
+
+/* flag representing the memory block allocation status */
+#define OBJECT_ALLOCATED	(1 << 0)
+/* flag set after the first reporting of an unreference object */
+#define OBJECT_REPORTED		(1 << 1)
+/* flag set to not scan the object */
+#define OBJECT_NO_SCAN		(1 << 2)
+
+/* the list of all allocated objects */
+static LIST_HEAD(object_list);
+/* the list of gray-colored objects (see color_gray comment below) */
+static LIST_HEAD(gray_list);
+/* prio search tree for object boundaries */
+static struct prio_tree_root object_tree_root;
+/* rw_lock protecting the access to object_list and prio_tree_root */
+static DEFINE_RWLOCK(kmemleak_lock);
+
+/* allocation caches for kmemleak internal data */
+static struct kmem_cache *object_cache;
+static struct kmem_cache *scan_area_cache;
+
+/* set if tracing memory operations is enabled */
+static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
+/* set in the late_initcall if there were no errors */
+static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
+/* enables or disables early logging of