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Subject[PATCH 2.6.19 01/10] Base support for kmemleak
Date
This patch adds the base support for the kernel memory leak detector. It
traces the memory allocation/freeing in a way similar to the Boehm's
conservative garbage collector, the difference being that the orphan
pointers are not freed but only shown in /proc/memleak. Enabling this
feature would introduce an overhead to memory allocations.

Signed-off-by: Catalin Marinas <catalin.marinas@gmail.com>
---
include/linux/kernel.h | 7
include/linux/memleak.h | 111 ++++
init/main.c | 3
lib/Kconfig.debug | 114 ++++
mm/Makefile | 1
mm/memleak.c | 1477 +++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 1711 insertions(+), 2 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index b9b5e4b..936a2ce 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -13,6 +13,7 @@
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/bitops.h>
+#include <linux/memleak.h>
#include <asm/byteorder.h>
#include <asm/bug.h>

@@ -300,9 +301,13 @@ static inline int __attribute__ ((format
* @member: the name of the member within the struct.
*
*/
-#define container_of(ptr, type, member) ({ \
+#define __container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
+#define container_of(ptr, type, member) ({ \
+ DECLARE_MEMLEAK_OFFSET(container_of, type, member); \
+ __container_of(ptr, type, member); \
+})

/*
* Check at compile time that something is of a particular type.
diff --git a/include/linux/memleak.h b/include/linux/memleak.h
new file mode 100644
index 0000000..39669bf
--- /dev/null
+++ b/include/linux/memleak.h
@@ -0,0 +1,111 @@
+/*
+ * include/linux/memleak.h
+ *
+ * Copyright (C) 2006 ARM Limited
+ * Written by Catalin Marinas <catalin.marinas@gmail.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 __MEMLEAK_H
+#define __MEMLEAK_H
+
+#include <linux/stddef.h>
+
+struct memleak_offset {
+ unsigned long type_id;
+ unsigned long member_type_id;
+ unsigned long offset;
+};
+
+/* type id approximation */
+#define ml_guess_typeid(size) ((unsigned long)(size))
+#define ml_typeid(type) ml_guess_typeid(sizeof(type))
+#define ml_sizeof(typeid) ((size_t)(typeid))
+
+#ifdef CONFIG_DEBUG_MEMLEAK
+
+/* if offsetof(type, member) is not a constant known at compile time,
+ * just use 0 instead since we cannot add it to the
+ * .init.memleak_offsets section
+ */
+#define memleak_offsetof(type, member) \
+ (__builtin_constant_p(offsetof(type, member)) ? \
+ offsetof(type, member) : 0)
+
+#define DECLARE_MEMLEAK_OFFSET(name, type, member) \
+ static const struct memleak_offset \
+ __attribute__ ((__section__ (".init.memleak_offsets"))) \
+ __attribute_used__ __memleak_offset__##name = { \
+ ml_typeid(type), \
+ ml_typeid(typeof(((type *)0)->member)), \
+ memleak_offsetof(type, member) \
+ }
+
+extern void memleak_init(void);
+extern void memleak_alloc(const void *ptr, size_t size, int ref_count);
+extern void memleak_free(const void *ptr);
+extern void memleak_padding(const void *ptr, unsigned long offset, size_t size);
+extern void memleak_not_leak(const void *ptr);
+extern void memleak_ignore(const void *ptr);
+extern void memleak_scan_area(const void *ptr, unsigned long offset, size_t length);
+extern void memleak_insert_aliases(struct memleak_offset *ml_off_start,
+ struct memleak_offset *ml_off_end);
+
+static inline void memleak_erase(void **ptr)
+{
+ *ptr = NULL;
+}
+
+#define memleak_container(type, member) { \
+ DECLARE_MEMLEAK_OFFSET(container_of, type, member); \
+}
+
+extern void memleak_typeid_raw(const void *ptr, unsigned long type_id);
+#define memleak_typeid(ptr, type) \
+ memleak_typeid_raw(ptr, ml_typeid(type))
+
+#else
+
+#define DECLARE_MEMLEAK_OFFSET(name, type, member)
+
+static inline void memleak_init(void)
+{ }
+static inline void memleak_alloc(const void *ptr, size_t size, int ref_count)
+{ }
+static inline void memleak_free(const void *ptr)
+{ }
+static inline void memleak_padding(const void *ptr, unsigned long offset, size_t size)
+{ }
+static inline void memleak_not_leak(const void *ptr)
+{ }
+static inline void memleak_ignore(const void *ptr)
+{ }
+static inline void memleak_scan_area(const void *ptr, unsigned long offset, size_t length)
+{ }
+static inline void memleak_insert_aliases(struct memleak_offset *ml_off_start,
+ struct memleak_offset *ml_off_end)
+{ }
+static inline void memleak_erase(void **ptr)
+{ }
+
+#define memleak_container(type, member)
+
+static inline void memleak_typeid_raw(const void *ptr, unsigned long type_id)
+{ }
+#define memleak_typeid(ptr, type)
+
+#endif /* CONFIG_DEBUG_MEMLEAK */
+
+#endif /* __MEMLEAK_H */
diff --git a/init/main.c b/init/main.c
index 36f608a..39be647 100644
--- a/init/main.c
+++ b/init/main.c
@@ -571,6 +571,8 @@ asmlinkage void __init start_kernel(void
cpuset_init_early();
mem_init();
kmem_cache_init();
+ radix_tree_init();
+ memleak_init();
setup_per_cpu_pageset();
numa_policy_init();
if (late_time_init)
@@ -591,7 +593,6 @@ asmlinkage void __init start_kernel(void
key_init();
security_init();
vfs_caches_init(num_physpages);
- radix_tree_init();
signals_init();
/* rootfs populating might need page-writeback */
page_writeback_init();
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d367910..2dda93b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -112,6 +112,120 @@ config DEBUG_SLAB_LEAK
bool "Memory leak debugging"
depends on DEBUG_SLAB

+menuconfig DEBUG_MEMLEAK
+ bool "Kernel memory leak detector"
+ default n
+ depends on EXPERIMENTAL && DEBUG_SLAB
+ select DEBUG_FS
+ select STACKTRACE
+ select FRAME_POINTER
+ 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/memleak. Enabling this
+ feature will introduce an overhead to memory
+ allocations. See Documentation/kmemleak.txt for more
+ details.
+
+ In order to access the memleak file, debugfs needs to be
+ mounted (usually at /sys/kernel/debug).
+
+config DEBUG_MEMLEAK_HASH_BITS
+ int "Pointer hash bits"
+ default 16
+ depends on DEBUG_MEMLEAK
+ help
+ This option sets the number of bits used for the pointer
+ hash table. Higher values give better memory scanning
+ performance but also lead to bigger RAM usage. The size of
+ the allocated hash table is (sizeof(void*) * 2^hash_bits).
+
+ The minimum recommended value is 16. A maximum value of
+ around 20 should be sufficient.
+
+config DEBUG_MEMLEAK_TRACE_LENGTH
+ int "Stack trace length"
+ default 4
+ depends on DEBUG_MEMLEAK && FRAME_POINTER
+ help
+ This option sets the length of the stack trace for the
+ allocated objects tracked by kmemleak.
+
+config DEBUG_MEMLEAK_PREINIT_OBJECTS
+ int "Pre-init actions buffer size"
+ default 512
+ depends on DEBUG_MEMLEAK
+ help
+ This is the buffer for storing the memory allocation/freeing
+ calls before kmemleak is fully initialized. Each element in
+ the buffer takes 24 bytes on a 32 bit architecture. This
+ buffer will be freed once the system initialization is
+ completed.
+
+config DEBUG_MEMLEAK_SECONDARY_ALIASES
+ bool "Create secondary level pointer aliases"
+ default y
+ depends on DEBUG_MEMLEAK
+ help
+ This option creates aliases for container_of(container_of(member))
+ access to objects. Disabling this option reduces the chances of
+ false negatives but it can slightly increase the number of false
+ positives.
+
+config DEBUG_MEMLEAK_TASK_STACKS
+ bool "Scan task kernel stacks"
+ default y
+ depends on DEBUG_MEMLEAK
+ help
+ This option enables the scanning of the task kernel
+ stacks. This option can introduce false negatives because of
+ the randomness of stacks content.
+
+ If unsure, say Y.
+
+config DEBUG_MEMLEAK_ORPHAN_FREEING
+ bool "Notify when freeing orphan objects"
+ default n
+ depends on DEBUG_MEMLEAK
+ help
+ This option enables the notification when objects
+ considered leaks are freed. The stack dump and the object
+ information displayed allow an easier identification of
+ false positives. Use this mainly for debugging kmemleak.
+
+ If unsure, say N.
+
+config DEBUG_MEMLEAK_REPORT_THLD
+ int "Unreferenced reporting threshold"
+ default 1
+ depends on DEBUG_MEMLEAK
+ help
+ This option sets the number of times an object needs to be
+ detected as unreferenced before being reported as a memory
+ leak. A value of 0 means that the object will be reported
+ the first time it is found as unreferenced. Other positive
+ values mean that the object needs to be found as
+ unreferenced a specified number of times prior to being
+ reported.
+
+ This is useful to avoid the reporting of transient false
+ positives where the pointers might be held in CPU registers,
+ especially on SMP systems, or on the stack when the stack
+ scanning option is disabled.
+
+config DEBUG_MEMLEAK_REPORTS_NR
+ int "Maximum number of reported leaks"
+ default 100
+ depends on DEBUG_MEMLEAK
+ help
+ This option sets the maximum number of leaks reported. If
+ this number is too big and there are leaks to be reported,
+ reading the /sys/kernel/debug/memleak file could lead to
+ some soft-locks.
+
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
diff --git a/mm/Makefile b/mm/Makefile
index f3c077e..aafe03f 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_MEMORY_HOTPLUG) += memory_h
obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
obj-$(CONFIG_SMP) += allocpercpu.o
+obj-$(CONFIG_DEBUG_MEMLEAK) += memleak.o
diff --git a/mm/memleak.c b/mm/memleak.c
new file mode 100644
index 0000000..db62a1d
--- /dev/null
+++ b/mm/memleak.c
@@ -0,0 +1,1477 @@
+/*
+ * mm/memleak.c
+ *
+ * Copyright (C) 2006 ARM Limited
+ * Written by Catalin Marinas <catalin.marinas@gmail.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
+ *
+ *
+ * Notes on locking
+ *
+ * Kmemleak needs to allocate/free memory for its own data structures:
+ * the memleak_object, the pointer hash and aliases radix trees. The
+ * memleak_free hook can be called from mm/slab.c with the list_lock
+ * held (i.e. when releasing off-slab management structures) and it
+ * will ackquire the memleak_lock. To avoid deadlocks caused by
+ * locking dependency, the list_lock must not be acquired while
+ * memleak_lock is held. This is ensured by not allocating/freeing
+ * memory while any of the kmemleak locks are held.
+ *
+ * The kmemleak hooks cannot be called concurrently on the same
+ * memleak_object (this is due to the way they were inserted in the
+ * kernel).
+ *
+ * The following locks are present in kmemleak:
+ *
+ * - alias_tree_lock - rwlock for accessing the radix tree holding the
+ * objects type information
+ *
+ * - memleak_lock - global kmemleak lock; protects object_list,
+ * last_object, pointer_hash and memleak_object structures
+ *
+ * Locking dependencies:
+ *
+ * - alias_tree_lock --> l3->list_lock
+ * - l3->list_lock --> memleak_lock
+ */
+
+/* #define DEBUG */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/radix-tree.h>
+#include <linux/gfp.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kallsyms.h>
+#include <linux/mman.h>
+#include <linux/nodemask.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/cpumask.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/hash.h>
+#include <linux/stacktrace.h>
+
+#include <asm/bitops.h>
+#include <asm/sections.h>
+#include <asm/percpu.h>
+#include <asm/processor.h>
+#include <asm/thread_info.h>
+#include <asm/atomic.h>
+
+#include <linux/memleak.h>
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+#define BUG_ON_LOCKING(cond) BUG_ON(cond)
+#else
+#define BUG_ON_LOCKING(cond)
+#endif
+
+#define MAX_TRACE CONFIG_DEBUG_MEMLEAK_TRACE_LENGTH
+#define SCAN_BLOCK_SIZE 4096 /* maximum scan length with interrupts disabled */
+#define PREINIT_OBJECTS CONFIG_DEBUG_MEMLEAK_PREINIT_OBJECTS
+#define HASH_BITS CONFIG_DEBUG_MEMLEAK_HASH_BITS
+#define BYTES_PER_WORD sizeof(void *)
+
+extern struct memleak_offset __memleak_offsets_start[];
+extern struct memleak_offset __memleak_offsets_end[];
+
+struct memleak_alias {
+ struct hlist_node node;
+ unsigned long offset;
+};
+
+struct memleak_scan_area {
+ struct hlist_node node;
+ unsigned long offset;
+ size_t length;
+};
+
+struct memleak_object {
+ unsigned long flags;
+ struct list_head object_list;
+ struct list_head gray_list;
+ struct rcu_head rcu;
+ int use_count;
+ unsigned long pointer;
+ unsigned long offset; /* padding */
+ size_t size;
+ unsigned long type_id;
+ int ref_count; /* the minimum encounters of the value */
+ int count; /* the ecounters of the value */
+ int report_thld; /* the unreferenced reporting threshold */
+ struct hlist_head *alias_list;
+ struct hlist_head area_list; /* areas to be scanned (or empty for all) */
+ unsigned long trace[MAX_TRACE];
+ unsigned int trace_len;
+};
+
+struct hash_node {
+ struct hlist_node node;
+ unsigned long val;
+ void *object;
+};
+
+enum memleak_action {
+ MEMLEAK_ALLOC,
+ MEMLEAK_FREE,
+ MEMLEAK_PADDING,
+ MEMLEAK_NOT_LEAK,
+ MEMLEAK_IGNORE,
+ MEMLEAK_SCAN_AREA,
+ MEMLEAK_TYPEID
+};
+
+struct memleak_preinit_object {
+ enum memleak_action type;
+ const void *pointer;
+ unsigned long offset;
+ size_t size;
+ unsigned long type_id;
+ int ref_count;
+};
+
+/* Tree storing the pointer aliases indexed by size */
+static RADIX_TREE(alias_tree, GFP_ATOMIC);
+static DEFINE_RWLOCK(alias_tree_lock);
+/* Hash storing all the possible objects, indexed by the pointer value */
+static struct hlist_head *pointer_hash;
+/* The list of all allocated objects */
+static LIST_HEAD(object_list);
+/* The list of the gray objects */
+static LIST_HEAD(gray_list);
+
+static struct kmem_cache *object_cache;
+/* The main lock for protecting the object lists and radix trees */
+static DEFINE_SPINLOCK(memleak_lock);
+static cpumask_t memleak_cpu_mask = CPU_MASK_NONE;
+static atomic_t memleak_initialized = ATOMIC_INIT(0);
+static int __initdata preinit_pos;
+static struct memleak_preinit_object __initdata preinit_objects[PREINIT_OBJECTS];
+/* last allocated object (optimization); protected by memleak_lock */
+static struct memleak_object *last_object;
+static int reported_leaks;
+
+/* object flags */
+#define OBJECT_ALLOCATED 0x1
+#define OBJECT_TYPE_GUESSED 0x2
+
+/* Hash functions */
+static void hash_init(void)
+{
+ unsigned int i;
+ unsigned int hash_size = sizeof(*pointer_hash) * (1 << HASH_BITS);
+ unsigned int hash_order = fls(hash_size) - 1;
+
+ /* hash_size not a power of 2 */
+ if (hash_size & ((1 << hash_order) - 1))
+ hash_order += 1;
+ if (hash_order < PAGE_SHIFT)
+ hash_order = PAGE_SHIFT;
+
+ pointer_hash = (struct hlist_head *)
+ __get_free_pages(GFP_ATOMIC, hash_order - PAGE_SHIFT);
+ if (!pointer_hash)
+ panic("kmemleak: cannot allocate the pointer hash\n");
+
+ for (i = 0; i < (1 << HASH_BITS); i++)
+ INIT_HLIST_HEAD(&pointer_hash[i]);
+}
+
+static struct hash_node *__hash_lookup_node(unsigned long val)
+{
+ struct hlist_node *elem;
+ struct hash_node *hnode;
+ unsigned long index = hash_long(val, HASH_BITS);
+
+ hlist_for_each_entry(hnode, elem, &pointer_hash[index], node) {
+ if (hnode->val == val)
+ return hnode;
+ }
+ return NULL;
+}
+
+static int hash_insert(unsigned long val, void *object)
+{
+ unsigned long flags;
+ unsigned long index = hash_long(val, HASH_BITS);
+ struct hash_node *hnode = kmalloc(sizeof(*hnode), GFP_ATOMIC);
+
+ if (!hnode)
+ return -ENOMEM;
+ INIT_HLIST_NODE(&hnode->node);
+ hnode->val = val;
+ hnode->object = object;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+ hlist_add_head(&hnode->node, &pointer_hash[index]);
+ spin_unlock_irqrestore(&memleak_lock, flags);
+
+ return 0;
+}
+
+static void *hash_delete(unsigned long val)
+{
+ unsigned long flags;
+ void *object = NULL;
+ struct hash_node *hnode;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+ hnode = __hash_lookup_node(val);
+ if (hnode) {
+ object = hnode->object;
+ hlist_del(&hnode->node);
+ }
+ spin_unlock_irqrestore(&memleak_lock, flags);
+
+ kfree(hnode);
+ return object;
+}
+
+/* memleak_lock held by the calling function and interrupts disabled */
+static void *hash_lookup(unsigned long val)
+{
+ struct hash_node *hnode;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+ BUG_ON_LOCKING(!spin_is_locked(&memleak_lock));
+
+ hnode = __hash_lookup_node(val);
+ if (hnode)
+ return hnode->object;
+ return NULL;
+}
+
+/* helper macros to avoid recursive calls. After disabling the
+ * interrupts, the only calls to this function on the same CPU should
+ * be from kmemleak itself and we can either ignore them or
+ * panic. Calls from other CPU's should be protected by spinlocks */
+#define recursive_enter(cpu_id, flags) ({ \
+ local_irq_save(flags); \
+ cpu_id = get_cpu(); \
+ cpu_test_and_set(cpu_id, memleak_cpu_mask); \
+})
+
+#define recursive_clear(cpu_id) do { \
+ cpu_clear(cpu_id, memleak_cpu_mask); \
+} while (0)
+
+#define recursive_exit(flags) do { \
+ put_cpu_no_resched(); \
+ local_irq_restore(flags); \
+} while (0)
+
+/* Object colors, encoded with count and ref_count:
+ * - white - orphan object, i.e. not enough references to it (ref_count >= 1)
+ * - gray - referred at least once and therefore non-orphan (ref_count == 0)
+ * - black - ignore; it doesn't contain references (text section) (ref_count == -1) */
+static inline int color_white(const struct memleak_object *object)
+{
+ return object->count != -1 && object->count < object->ref_count;
+}
+
+static inline int color_gray(const struct memleak_object *object)
+{
+ return object->ref_count != -1 && object->count >= object->ref_count;
+}
+
+static inline int color_black(const struct memleak_object *object)
+{
+ return object->ref_count == -1;
+}
+
+#ifdef DEBUG
+static inline void dump_object_internals(struct memleak_object *object)
+{
+ struct memleak_alias *alias;
+ struct hlist_node *elem;
+
+ printk(KERN_NOTICE " size = %d\n", object->size);
+ printk(KERN_NOTICE " ref_count = %d\n", object->ref_count);
+ printk(KERN_NOTICE " count = %d\n", object->count);
+ printk(KERN_NOTICE " aliases:\n");
+ if (object->alias_list) {
+ hlist_for_each_entry(alias, elem, object->alias_list, node)
+ printk(KERN_NOTICE " 0x%lx\n", alias->offset);
+ }
+}
+#else
+static inline void dump_object_internals(struct memleak_object *object)
+{ }
+#endif
+
+static void dump_object_info(struct memleak_object *object)
+{
+ struct stack_trace trace;
+
+ trace.nr_entries = object->trace_len;
+ trace.entries = object->trace;
+
+ printk(KERN_NOTICE "kmemleak: object 0x%08lx:\n", object->pointer);
+ dump_object_internals(object);
+ printk(KERN_NOTICE " trace:\n");
+ print_stack_trace(&trace, 4);
+}
+
+/* Insert an element into the aliases radix tree.
+ * Return 0 on success. */
+static int insert_alias(unsigned long type_id, unsigned long offset)
+{
+ int ret = 0;
+ struct hlist_head *alias_list;
+ struct hlist_node *elem;
+ struct memleak_alias *alias;
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (type_id == 0 || offset == 0 || offset >= ml_sizeof(type_id))
+ return -EINVAL;
+
+ if (recursive_enter(cpu_id, flags))
+ BUG();
+ write_lock(&alias_tree_lock);
+
+ offset &= ~(BYTES_PER_WORD - 1);
+
+ alias_list = radix_tree_lookup(&alias_tree, type_id);
+ if (!alias_list) {
+ /* no alias list for this type id. Allocate list_head
+ * and insert into the radix tree */
+ alias_list = kmalloc(sizeof(*alias_list), GFP_ATOMIC);
+ if (!alias_list)
+ panic("kmemleak: cannot allocate alias_list\n");
+ INIT_HLIST_HEAD(alias_list);
+
+ ret = radix_tree_insert(&alias_tree, type_id, alias_list);
+ if (ret)
+ panic("kmemleak: cannot insert into the aliases radix tree: %d\n", ret);
+ }
+
+ hlist_for_each_entry(alias, elem, alias_list, node) {
+ if (alias->offset == offset) {
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ alias = kmalloc(sizeof(*alias), GFP_ATOMIC);
+ if (!alias)
+ panic("kmemleak: cannot allocate initial memory\n");
+ INIT_HLIST_NODE(&alias->node);
+ alias->offset = offset;
+
+ hlist_add_head_rcu(&alias->node, alias_list);
+
+ out:
+ write_unlock(&alias_tree_lock);
+ recursive_clear(cpu_id);
+ recursive_exit(flags);
+
+ return ret;
+}
+
+/* Insert pointer aliases from the given array */
+void memleak_insert_aliases(struct memleak_offset *ml_off_start,
+ struct memleak_offset *ml_off_end)
+{
+ struct memleak_offset *ml_off;
+ int i = 0;
+#ifdef CONFIG_DEBUG_MEMLEAK_SECONDARY_ALIASES
+ unsigned long flags;
+#endif
+
+ pr_debug("%s(0x%p, 0x%p)\n", __FUNCTION__, ml_off_start, ml_off_end);
+
+ /* primary aliases - container_of(member) */
+ for (ml_off = ml_off_start; ml_off < ml_off_end; ml_off++)
+ if (!insert_alias(ml_off->type_id, ml_off->offset))
+ i++;
+ pr_debug("kmemleak: found %d primary alias(es)\n", i);
+
+#ifdef CONFIG_DEBUG_MEMLEAK_SECONDARY_ALIASES
+ /* secondary aliases - container_of(container_of(member)) */
+ for (ml_off = ml_off_start; ml_off < ml_off_end; ml_off++) {
+ struct hlist_head *alias_list;
+ struct memleak_alias *alias;
+ struct hlist_node *elem;
+
+ /* with imprecise type identification, if the member
+ * id is the same as the outer structure id, just
+ * ignore as any potential aliases are already in the
+ * tree */
+ if (ml_off->member_type_id == ml_off->type_id)
+ continue;
+
+ read_lock_irqsave(&alias_tree_lock, flags);
+ alias_list = radix_tree_lookup(&alias_tree, ml_off->member_type_id);
+ read_unlock_irqrestore(&alias_tree_lock, flags);
+ if (!alias_list)
+ continue;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(alias, elem, alias_list, node)
+ if (!insert_alias(ml_off->type_id, ml_off->offset + alias->offset))
+ i++;
+ rcu_read_unlock();
+ }
+ pr_debug("kmemleak: found %d alias(es)\n", i);
+#endif
+}
+EXPORT_SYMBOL_GPL(memleak_insert_aliases);
+
+/* called with interrupts disabled */
+static inline struct memleak_object *get_cached_object(unsigned long ptr)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ spin_lock(&memleak_lock);
+ if (!last_object || ptr != last_object->pointer)
+ last_object = hash_lookup(ptr);
+ object = last_object;
+ spin_unlock(&memleak_lock);
+
+ return object;
+}
+
+/* no need for atomic operations since memleak_lock is already held
+ * and interrupts disabled. Return 1 if successful or 0 otherwise */
+static inline int get_object(struct memleak_object *object)
+{
+ BUG_ON_LOCKING(!irqs_disabled());
+ BUG_ON_LOCKING(!spin_is_locked(&memleak_lock));
+
+ if (object->use_count != 0)
+ object->use_count++;
+ return object->use_count != 0;
+}
+
+static void free_object_rcu(struct rcu_head *rcu)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+ struct hlist_node *elem, *tmp;
+ struct memleak_scan_area *area;
+ struct memleak_object *object =
+ container_of(rcu, struct memleak_object, rcu);
+
+ if (recursive_enter(cpu_id, flags))
+ BUG();
+
+ /* once use_count is 0, there is no code accessing the object */
+ hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) {
+ hlist_del(elem);
+ kfree(area);
+ }
+ kmem_cache_free(object_cache, object);
+
+ recursive_clear(cpu_id);
+ recursive_exit(flags);
+}
+
+/* called without memleak_lock held */
+static void put_object(struct memleak_object *object)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+
+ if (--object->use_count > 0)
+ goto out;
+
+ /* should only get here after delete_object was called */
+ BUG_ON(object->flags & OBJECT_ALLOCATED);
+
+ /* the last reference to this object */
+ list_del_rcu(&object->object_list);
+ call_rcu(&object->rcu, free_object_rcu);
+
+ out:
+ spin_unlock_irqrestore(&memleak_lock, flags);
+}
+
+/* called with interrupts disabled (no need to hold the memleak_lock
+ * as the the pointer aliases functions cannot be called concurrently
+ * on the same object) */
+static void delete_pointer_aliases(struct memleak_object *object)
+{
+ struct memleak_alias *alias;
+ struct hlist_node *elem;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ if (object->offset)
+ hash_delete(object->pointer + object->offset);
+
+ if (object->alias_list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(alias, elem, object->alias_list, node)
+ hash_delete(object->pointer
+ + object->offset + alias->offset);
+ rcu_read_unlock();
+ object->alias_list = NULL;
+ }
+}
+
+/* called with interrupts disabled (see above for why memleak_lock
+ * doesn't need to be held) */
+static void create_pointer_aliases(struct memleak_object *object)
+{
+ struct memleak_alias *alias;
+ struct hlist_node *elem;
+ int err;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ if (object->offset) {
+ err = hash_insert(object->pointer + object->offset, object);
+ if (err) {
+ dump_stack();
+ panic("kmemleak: cannot insert offset into the pointer hash table: %d\n", err);
+ }
+ }
+
+ read_lock(&alias_tree_lock);
+ object->alias_list = radix_tree_lookup(&alias_tree, object->type_id);
+ read_unlock(&alias_tree_lock);
+
+ if (object->alias_list) {
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(alias, elem, object->alias_list, node) {
+ err = hash_insert(object->pointer + object->offset
+ + alias->offset, object);
+ if (err) {
+ dump_stack();
+ panic("kmemleak: cannot insert alias into the pointer hash table: %d\n", err);
+ }
+ }
+ rcu_read_unlock();
+ }
+}
+
+/* Insert a pointer and its aliases into the pointer hash table */
+static inline void create_object(unsigned long ptr, size_t size, int ref_count)
+{
+ struct memleak_object *object;
+ int err;
+ struct stack_trace trace;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = kmem_cache_alloc(object_cache, SLAB_ATOMIC);
+ if (!object)
+ panic("kmemleak: cannot allocate a memleak_object structure\n");
+
+ INIT_LIST_HEAD(&object->object_list);
+ INIT_LIST_HEAD(&object->gray_list);
+ INIT_HLIST_HEAD(&object->area_list);
+ object->flags = OBJECT_TYPE_GUESSED;
+ object->use_count = 1;
+ object->pointer = ptr;
+ object->offset = 0;
+ object->size = size;
+ object->type_id = ml_guess_typeid(size); /* type id approximation */
+ object->ref_count = ref_count;
+ object->count = -1;
+ object->report_thld = CONFIG_DEBUG_MEMLEAK_REPORT_THLD;
+ object->alias_list = NULL;
+
+ trace.max_entries = MAX_TRACE;
+ trace.nr_entries = 0;
+ trace.entries = object->trace;
+ trace.skip = 2;
+ trace.all_contexts = 0;
+ save_stack_trace(&trace, NULL);
+
+ object->trace_len = trace.nr_entries;
+
+ spin_lock(&memleak_lock);
+ /* object->use_count already set to 1 */
+ list_add_tail_rcu(&object->object_list, &object_list);
+ spin_unlock(&memleak_lock);
+
+ err = hash_insert(ptr, object);
+ if (err) {
+ dump_stack();
+ if (err == -EEXIST) {
+ printk(KERN_NOTICE "Existing pointer:\n");
+ spin_lock(&memleak_lock);
+ object = hash_lookup(ptr);
+ dump_object_info(object);
+ spin_unlock(&memleak_lock);
+ }
+ panic("kmemleak: cannot insert 0x%lx into the pointer hash table: %d\n",
+ ptr, err);
+ }
+
+ create_pointer_aliases(object);
+
+ /* everything completed fine, just mark the object as allocated */
+ spin_lock(&memleak_lock);
+ object->flags |= OBJECT_ALLOCATED;
+ last_object = object;
+ spin_unlock(&memleak_lock);
+}
+
+/* Remove a pointer and its aliases from the pointer hash table */
+static inline void delete_object(unsigned long ptr)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = hash_delete(ptr);
+ if (!object) {
+ dump_stack();
+ printk(KERN_WARNING "kmemleak: freeing unknown object at 0x%08lx\n", ptr);
+ return;
+ }
+
+ spin_lock(&memleak_lock);
+
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: freeing object by alias 0x%08lx\n", ptr);
+ }
+ BUG_ON(!(object->flags & OBJECT_ALLOCATED));
+
+ object->flags &= ~OBJECT_ALLOCATED;
+
+ /* deleting the cached object */
+ if (last_object && ptr == last_object->pointer)
+ last_object = NULL;
+
+#ifdef CONFIG_DEBUG_MEMLEAK_ORPHAN_FREEING
+ if (color_white(object)) {
+ dump_stack();
+ dump_object_info(object);
+ printk(KERN_WARNING "kmemleak: freeing orphan object 0x%08lx\n", ptr);
+ }
+#endif
+
+ spin_unlock(&memleak_lock);
+
+ delete_pointer_aliases(object);
+ object->pointer = 0;
+ put_object(object);
+}
+
+/* Re-create the pointer aliases according to the new size/offset
+ * information */
+static inline void unpad_object(unsigned long ptr, unsigned long offset,
+ size_t size)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = get_cached_object(ptr);
+ if (!object) {
+ dump_stack();
+ panic("kmemleak: resizing unknown object at 0x%08lx\n", ptr);
+ }
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: resizing object by alias 0x%08lx\n", ptr);
+ }
+ if (offset + size > object->size) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: new boundaries exceed object 0x%08lx\n", ptr);
+ }
+
+ /* nothing changed */
+ if (offset == object->offset && size == object->size)
+ return;
+
+ /* re-create the pointer aliases */
+ delete_pointer_aliases(object);
+
+ spin_lock(&memleak_lock);
+ object->offset = offset;
+ object->size = size;
+ if (object->flags & OBJECT_TYPE_GUESSED)
+ object->type_id = ml_guess_typeid(size);
+ spin_unlock(&memleak_lock);
+
+ create_pointer_aliases(object);
+}
+
+/* Make a object permanently gray (false positive) */
+static inline void make_gray_object(unsigned long ptr)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = get_cached_object(ptr);
+ if (!object) {
+ dump_stack();
+ panic("kmemleak: graying unknown object at 0x%08lx\n", ptr);
+ }
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: graying object by alias 0x%08lx\n", ptr);
+ }
+
+ spin_lock(&memleak_lock);
+ object->ref_count = 0;
+ spin_unlock(&memleak_lock);
+}
+
+/* Mark the object as black */
+static inline void make_black_object(unsigned long ptr)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = get_cached_object(ptr);
+ if (!object) {
+ dump_stack();
+ panic("kmemleak: blacking unknown object at 0x%08lx\n", ptr);
+ }
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: blacking object by alias 0x%08lx\n", ptr);
+ }
+
+ spin_lock(&memleak_lock);
+ object->ref_count = -1;
+ spin_unlock(&memleak_lock);
+}
+
+/* Add a scanning area to the object */
+static inline void add_scan_area(unsigned long ptr, unsigned long offset, size_t length)
+{
+ struct memleak_object *object;
+ struct memleak_scan_area *area;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ area = kmalloc(sizeof(*area), GFP_ATOMIC);
+ if (!area)
+ panic("kmemleak: cannot allocate a scan area\n");
+
+ INIT_HLIST_NODE(&area->node);
+ area->offset = offset;
+ area->length = length;
+
+ object = get_cached_object(ptr);
+ if (!object) {
+ dump_stack();
+ panic("kmemleak: adding scan area to unknown object at 0x%08lx\n", ptr);
+ }
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: adding scan area to object by alias 0x%08lx\n", ptr);
+ }
+ if (offset + length > object->size) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: scan area larger than object 0x%08lx\n", ptr);
+ }
+
+ spin_lock(&memleak_lock);
+ hlist_add_head(&area->node, &object->area_list);
+ spin_unlock(&memleak_lock);
+}
+
+/* Re-create the pointer aliases according to the new type id */
+static inline void change_type_id(unsigned long ptr, unsigned long type_id)
+{
+ struct memleak_object *object;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+
+ object = get_cached_object(ptr);
+ if (!object) {
+ dump_stack();
+ panic("kmemleak: changing type of unknown object at 0x%08lx\n", ptr);
+ }
+ if (object->pointer != ptr) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: changing type of object by alias 0x%08lx\n", ptr);
+ }
+ if (ml_sizeof(type_id) > object->size) {
+ dump_stack();
+ dump_object_info(object);
+ panic("kmemleak: new type larger than object 0x%08lx\n", ptr);
+ }
+
+ spin_lock(&memleak_lock);
+ object->type_id = type_id;
+ object->flags &= ~OBJECT_TYPE_GUESSED;
+ spin_unlock(&memleak_lock);
+
+ if (type_id == object->type_id)
+ return;
+
+ delete_pointer_aliases(object);
+ create_pointer_aliases(object);
+}
+
+/* Allocation function hook */
+void memleak_alloc(const void *ptr, size_t size, int ref_count)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p, %d, %d)\n", __FUNCTION__, ptr, size, ref_count);
+
+ if (!atomic_read(&memleak_initialized)) {
+ /* no need for SMP locking since this object is
+ * executed before the other CPUs are started */
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_ALLOC;
+ object->pointer = ptr;
+ object->size = size;
+ object->ref_count = ref_count;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ create_object((unsigned long)ptr, size, ref_count);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL_GPL(memleak_alloc);
+
+/* Freeing function hook */
+void memleak_free(const void *ptr)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p)\n", __FUNCTION__, ptr);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_FREE;
+ object->pointer = ptr;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ delete_object((unsigned long)ptr);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL_GPL(memleak_free);
+
+/* Change the size and location information of an allocated memory
+ * object (this is needed for allocations padding the object) */
+void memleak_padding(const void *ptr, unsigned long offset, size_t size)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p, %d)\n", __FUNCTION__, ptr, size);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_PADDING;
+ object->pointer = ptr;
+ object->offset = offset;
+ object->size = size;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ unpad_object((unsigned long)ptr, offset, size);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL(memleak_padding);
+
+/* Mark a object as a false positive */
+void memleak_not_leak(const void *ptr)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p)\n", __FUNCTION__, ptr);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_NOT_LEAK;
+ object->pointer = ptr;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ make_gray_object((unsigned long)ptr);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL(memleak_not_leak);
+
+/* Ignore this memory object */
+void memleak_ignore(const void *ptr)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p)\n", __FUNCTION__, ptr);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_IGNORE;
+ object->pointer = ptr;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ make_black_object((unsigned long)ptr);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL(memleak_ignore);
+
+/* Add a scanning area to a object */
+void memleak_scan_area(const void *ptr, unsigned long offset, size_t length)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p)\n", __FUNCTION__, ptr);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_SCAN_AREA;
+ object->pointer = ptr;
+ object->offset = offset;
+ object->size = length;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ add_scan_area((unsigned long)ptr, offset, length);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL(memleak_scan_area);
+
+/* Change the type id of an allocated memory object */
+void memleak_typeid_raw(const void *ptr, unsigned long type_id)
+{
+ unsigned long flags;
+ unsigned int cpu_id;
+
+ if (!ptr)
+ return;
+ if (!type_id)
+ return;
+
+ if (recursive_enter(cpu_id, flags))
+ goto out;
+
+ pr_debug("%s(0x%p, %ld)\n", __FUNCTION__, ptr, type_id);
+
+ if (!atomic_read(&memleak_initialized)) {
+ struct memleak_preinit_object *object;
+
+ BUG_ON(cpu_id != 0);
+
+ if (preinit_pos < PREINIT_OBJECTS) {
+ object = &preinit_objects[preinit_pos];
+
+ object->type = MEMLEAK_TYPEID;
+ object->pointer = ptr;
+ object->type_id = type_id;
+ }
+ preinit_pos++;
+
+ goto clear;
+ }
+
+ change_type_id((unsigned long)ptr, type_id);
+
+ clear:
+ recursive_clear(cpu_id);
+ out:
+ recursive_exit(flags);
+}
+EXPORT_SYMBOL(memleak_typeid_raw);
+
+/* Scan a block of memory (exclusive range) for pointers and move
+ * those found to the gray list. This function is called with
+ * memleak_lock held and interrupts disabled */
+static void __scan_block(void *_start, void *_end)
+{
+ unsigned long *ptr;
+ unsigned long *start = (unsigned long *)ALIGN((unsigned long)_start,
+ BYTES_PER_WORD);
+ unsigned long *end = _end;
+
+ BUG_ON_LOCKING(!irqs_disabled());
+ BUG_ON_LOCKING(!spin_is_locked(&memleak_lock));
+
+ for (ptr = start; ptr < end; ptr++) {
+ struct memleak_object *object =
+ hash_lookup((*ptr) & ~(BYTES_PER_WORD - 1));
+ if (!object)
+ continue;
+ if (!color_white(object))
+ continue;
+
+ object->count++;
+ /* this can also happen during the gray_list traversal */
+ if (color_gray(object)) {
+ /* found in the hash, get_object() returns 1 */
+ get_object(object);
+ object->report_thld++;
+ list_add_tail(&object->gray_list, &gray_list);
+ }
+ }
+}
+
+static void scan_block(void *start, void *end)
+{
+ unsigned long flags;
+ void *s, *e;
+
+ s = start;
+ while (s < end) {
+ e = s + SCAN_BLOCK_SIZE;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+ __scan_block(s, e < end ? e : end);
+ spin_unlock_irqrestore(&memleak_lock, flags);
+
+ s = e;
+ }
+}
+
+/* Scan a memory block represented by a memleak_object */
+static inline void scan_object(struct memleak_object *object)
+{
+ struct memleak_scan_area *area;
+ struct hlist_node *elem;
+ unsigned long flags;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+
+ /* freed object */
+ if (!(object->flags & OBJECT_ALLOCATED))
+ goto out;
+
+ if (hlist_empty(&object->area_list))
+ __scan_block((void *)(object->pointer + object->offset),
+ (void *)(object->pointer + object->offset
+ + object->size));
+ else
+ hlist_for_each_entry(area, elem, &object->area_list, node)
+ __scan_block((void *)(object->pointer + area->offset),
+ (void *)(object->pointer + area->offset
+ + area->length));
+
+ out:
+ spin_unlock_irqrestore(&memleak_lock, flags);
+}
+
+/* Scan the memory and print the orphan objects */
+static void memleak_scan(void)
+{
+ unsigned long flags;
+ struct memleak_object *object, *tmp;
+#ifdef CONFIG_DEBUG_MEMLEAK_TASK_STACKS
+ struct task_struct *task;
+#endif
+ int i;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ spin_lock_irqsave(&memleak_lock, flags);
+
+ /* there should be a maximum of 1 reference to any
+ * object at this point */
+ BUG_ON(object->use_count > 1);
+
+ /* reset the reference count (whiten the object) */
+ object->count = 0;
+ if (color_gray(object) && get_object(object))
+ list_add_tail(&object->gray_list, &gray_list);
+ else
+ object->report_thld--;
+
+ spin_unlock_irqrestore(&memleak_lock, flags);
+ }
+ rcu_read_unlock();
+
+ /* data/bss scanning */
+ scan_block(_sdata, _edata);
+ scan_block(__bss_start, __bss_stop);
+
+#ifdef CONFIG_SMP
+ /* per-cpu scanning */
+ for_each_possible_cpu(i)
+ scan_block(__per_cpu_start + per_cpu_offset(i),
+ __per_cpu_end + per_cpu_offset(i));
+#endif
+
+ /* mem_map scanning */
+ for_each_online_node(i) {
+ struct page *page, *end;
+
+ page = NODE_MEM_MAP(i);
+ end = page + NODE_DATA(i)->node_spanned_pages;
+
+ scan_block(page, end);
+ }
+
+#ifdef CONFIG_DEBUG_MEMLEAK_TASK_STACKS
+ read_lock(&tasklist_lock);
+ for_each_process(task)
+ scan_block(task_stack_page(task),
+ task_stack_page(task) + THREAD_SIZE);
+ read_unlock(&tasklist_lock);
+#endif
+
+ /* scan the objects already referenced. More objects will be
+ * referenced and, if there are no memory leaks, all the
+ * objects will be scanned. The list traversal is safe for
+ * both tail additions and removals from inside the loop. The
+ * memleak objects cannot be freed from outside the loop
+ * because their use_count was increased */
+ object = list_entry(gray_list.next, typeof(*object), gray_list);
+ while (&object->gray_list != &gray_list) {
+ /* may add new objects to the list */
+ scan_object(object);
+
+ tmp = list_entry(object->gray_list.next, typeof(*object),
+ gray_list);
+
+ /* remove the object from the list and release it */
+ list_del(&object->gray_list);
+ put_object(object);
+
+ object = tmp;
+ }
+ BUG_ON(!list_empty(&gray_list));
+}
+
+static void *memleak_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct memleak_object *object;
+ loff_t n = *pos;
+ unsigned long flags;
+
+ if (!n) {
+ memleak_scan();
+ reported_leaks = 0;
+ }
+ if (reported_leaks >= CONFIG_DEBUG_MEMLEAK_REPORTS_NR)
+ return NULL;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ if (n-- > 0)
+ continue;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+ if (get_object(object)) {
+ spin_unlock_irqrestore(&memleak_lock, flags);
+ goto out;
+ }
+ spin_unlock_irqrestore(&memleak_lock, flags);
+ }
+ object = NULL;
+ out:
+ rcu_read_unlock();
+ return object;
+}
+
+static void *memleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct list_head *n;
+ struct memleak_object *next = NULL;
+ unsigned long flags;
+
+ ++(*pos);
+ if (reported_leaks >= CONFIG_DEBUG_MEMLEAK_REPORTS_NR)
+ return NULL;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+
+ n = ((struct memleak_object *)v)->object_list.next;
+ if (n != &object_list) {
+ next = list_entry(n, struct memleak_object, object_list);
+ /* still in the object_list, get_object() returns 1 */
+ get_object(next);
+ }
+
+ spin_unlock_irqrestore(&memleak_lock, flags);
+
+ put_object(v);
+ return next;
+}
+
+static void memleak_seq_stop(struct seq_file *seq, void *v)
+{
+ if (v)
+ put_object(v);
+}
+
+static int memleak_seq_show(struct seq_file *seq, void *v)
+{
+ const struct memleak_object *object = v;
+ unsigned long flags;
+ char namebuf[KSYM_NAME_LEN + 1] = "";
+ char *modname;
+ unsigned long symsize;
+ unsigned long offset = 0;
+ int i;
+
+ spin_lock_irqsave(&memleak_lock, flags);
+
+ if (!color_white(object))
+ goto out;
+ /* freed in the meantime (false positive) or just allocated */
+ if (!(object->flags & OBJECT_ALLOCATED))
+ goto out;
+ if (object->report_thld >= 0)
+ goto out;
+
+ reported_leaks++;
+ seq_printf(seq, "unreferenced object 0x%08lx (size %d):\n",
+ object->pointer, object->size);
+
+ for (i = 0; i < object->trace_len; i++) {
+ unsigned long trace = object->trace[i];
+
+ kallsyms_lookup(trace, &symsize, &offset, &modname, namebuf);
+ seq_printf(seq, " [<%08lx>] %s\n", trace, namebuf);
+ }
+
+ out:
+ spin_unlock_irqrestore(&memleak_lock, flags);
+ return 0;
+}
+
+static struct seq_operations memleak_seq_ops = {
+ .start = memleak_seq_start,
+ .next = memleak_seq_next,
+ .stop = memleak_seq_stop,
+ .show = memleak_seq_show,
+};
+
+static int memleak_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &memleak_seq_ops);
+}
+
+static struct file_operations memleak_fops = {
+ .owner = THIS_MODULE,
+ .open = memleak_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/* KMemLeak initialization. Set up the radix tree for the pointer aliases */
+void __init memleak_init(void)
+{
+ int i;
+ unsigned long flags;
+
+ hash_init();
+
+ object_cache = kmem_cache_create("memleak_object_cache", sizeof(struct memleak_object),
+ 0, SLAB_PANIC, NULL, NULL);
+ if (!object_cache)
+ panic("kmemleak: cannot create the object cache\n");
+
+ memleak_insert_aliases(__memleak_offsets_start, __memleak_offsets_end);
+
+ /* no need to hold the spinlock as SMP is not initialized
+ * yet. Holding it here would lead to a deadlock */
+ local_irq_save(flags);
+
+ atomic_set(&memleak_initialized, 1);
+
+ if (preinit_pos >= PREINIT_OBJECTS)
+ panic("kmemleak: preinit objects buffer overflow: %d\n",
+ preinit_pos);
+
+ /* execute the buffered memleak actions */
+ pr_debug("kmemleak: %d preinit actions\n", preinit_pos);
+ for (i = 0; i < preinit_pos; i++) {
+ struct memleak_preinit_object *object = &preinit_objects[i];
+
+ switch (object->type) {
+ case MEMLEAK_ALLOC:
+ memleak_alloc(object->pointer, object->size,
+ object->ref_count);
+ break;
+ case MEMLEAK_FREE:
+ memleak_free(object->pointer);
+ break;
+ case MEMLEAK_PADDING:
+ memleak_padding(object->pointer, object->offset,
+ object->size);
+ break;
+ case MEMLEAK_NOT_LEAK:
+ memleak_not_leak(object->pointer);
+ break;
+ case MEMLEAK_IGNORE:
+ memleak_ignore(object->pointer);
+ break;
+ case MEMLEAK_SCAN_AREA:
+ memleak_scan_area(object->pointer,
+ object->offset, object->size);
+ break;
+ case MEMLEAK_TYPEID:
+ memleak_typeid_raw(object->pointer, object->type_id);
+ break;
+ default:
+ BUG();
+ }
+ }
+
+ local_irq_restore(flags);
+
+ printk(KERN_INFO "Kernel memory leak detector initialized\n");
+}
+
+/* Late initialization function */
+int __init memleak_late_init(void)
+{
+ struct dentry *dentry;
+
+ dentry = debugfs_create_file("memleak", S_IRUGO, NULL, NULL,
+ &memleak_fops);
+ if (!dentry)
+ return -ENOMEM;
+
+ pr_debug("kmemleak: late initialization completed\n");
+
+ return 0;
+}
+late_initcall(memleak_late_init);
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