linux/lib/debugobjects.c
Waiman Long d5f34153e5 debugobjects: Move printk out of db->lock critical sections
The db->lock is a raw spinlock and so the lock hold time is supposed
to be short. This will not be the case when printk() is being involved
in some of the critical sections. In order to avoid the long hold time,
in case some messages need to be printed, the debug_object_is_on_stack()
and debug_print_object() calls are now moved out of those critical
sections.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: Qian Cai <cai@gmx.us>
Cc: Zhong Jiang <zhongjiang@huawei.com>
Link: https://lkml.kernel.org/r/20190520141450.7575-6-longman@redhat.com
2019-06-14 14:51:16 +02:00

1385 lines
34 KiB
C

/*
* Generic infrastructure for lifetime debugging of objects.
*
* Started by Thomas Gleixner
*
* Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
*
* For licencing details see kernel-base/COPYING
*/
#define pr_fmt(fmt) "ODEBUG: " fmt
#include <linux/debugobjects.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/hash.h>
#include <linux/kmemleak.h>
#define ODEBUG_HASH_BITS 14
#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
#define ODEBUG_POOL_SIZE 1024
#define ODEBUG_POOL_MIN_LEVEL 256
#define ODEBUG_POOL_PERCPU_SIZE 64
#define ODEBUG_BATCH_SIZE 16
#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
/*
* We limit the freeing of debug objects via workqueue at a maximum
* frequency of 10Hz and about 1024 objects for each freeing operation.
* So it is freeing at most 10k debug objects per second.
*/
#define ODEBUG_FREE_WORK_MAX 1024
#define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
struct debug_bucket {
struct hlist_head list;
raw_spinlock_t lock;
};
/*
* Debug object percpu free list
* Access is protected by disabling irq
*/
struct debug_percpu_free {
struct hlist_head free_objs;
int obj_free;
};
static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
static DEFINE_RAW_SPINLOCK(pool_lock);
static HLIST_HEAD(obj_pool);
static HLIST_HEAD(obj_to_free);
/*
* Because of the presence of percpu free pools, obj_pool_free will
* under-count those in the percpu free pools. Similarly, obj_pool_used
* will over-count those in the percpu free pools. Adjustments will be
* made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
* can be off.
*/
static int obj_pool_min_free = ODEBUG_POOL_SIZE;
static int obj_pool_free = ODEBUG_POOL_SIZE;
static int obj_pool_used;
static int obj_pool_max_used;
static bool obj_freeing;
/* The number of objs on the global free list */
static int obj_nr_tofree;
static int debug_objects_maxchain __read_mostly;
static int __maybe_unused debug_objects_maxchecked __read_mostly;
static int debug_objects_fixups __read_mostly;
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
static int debug_objects_pool_size __read_mostly
= ODEBUG_POOL_SIZE;
static int debug_objects_pool_min_level __read_mostly
= ODEBUG_POOL_MIN_LEVEL;
static struct debug_obj_descr *descr_test __read_mostly;
static struct kmem_cache *obj_cache __read_mostly;
/*
* Track numbers of kmem_cache_alloc()/free() calls done.
*/
static int debug_objects_allocated;
static int debug_objects_freed;
static void free_obj_work(struct work_struct *work);
static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
static int __init enable_object_debug(char *str)
{
debug_objects_enabled = 1;
return 0;
}
static int __init disable_object_debug(char *str)
{
debug_objects_enabled = 0;
return 0;
}
early_param("debug_objects", enable_object_debug);
early_param("no_debug_objects", disable_object_debug);
static const char *obj_states[ODEBUG_STATE_MAX] = {
[ODEBUG_STATE_NONE] = "none",
[ODEBUG_STATE_INIT] = "initialized",
[ODEBUG_STATE_INACTIVE] = "inactive",
[ODEBUG_STATE_ACTIVE] = "active",
[ODEBUG_STATE_DESTROYED] = "destroyed",
[ODEBUG_STATE_NOTAVAILABLE] = "not available",
};
static void fill_pool(void)
{
gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
struct debug_obj *obj;
unsigned long flags;
if (likely(obj_pool_free >= debug_objects_pool_min_level))
return;
/*
* Reuse objs from the global free list; they will be reinitialized
* when allocating.
*/
while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
raw_spin_lock_irqsave(&pool_lock, flags);
/*
* Recheck with the lock held as the worker thread might have
* won the race and freed the global free list already.
*/
while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_nr_tofree--;
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
if (unlikely(!obj_cache))
return;
while (obj_pool_free < debug_objects_pool_min_level) {
struct debug_obj *new[ODEBUG_BATCH_SIZE];
int cnt;
for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
if (!new[cnt])
break;
}
if (!cnt)
return;
raw_spin_lock_irqsave(&pool_lock, flags);
while (cnt) {
hlist_add_head(&new[--cnt]->node, &obj_pool);
debug_objects_allocated++;
obj_pool_free++;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
}
/*
* Lookup an object in the hash bucket.
*/
static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
{
struct debug_obj *obj;
int cnt = 0;
hlist_for_each_entry(obj, &b->list, node) {
cnt++;
if (obj->object == addr)
return obj;
}
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
return NULL;
}
/*
* Allocate a new object from the hlist
*/
static struct debug_obj *__alloc_object(struct hlist_head *list)
{
struct debug_obj *obj = NULL;
if (list->first) {
obj = hlist_entry(list->first, typeof(*obj), node);
hlist_del(&obj->node);
}
return obj;
}
/*
* Allocate a new object. If the pool is empty, switch off the debugger.
* Must be called with interrupts disabled.
*/
static struct debug_obj *
alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
{
struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
struct debug_obj *obj;
if (likely(obj_cache)) {
obj = __alloc_object(&percpu_pool->free_objs);
if (obj) {
percpu_pool->obj_free--;
goto init_obj;
}
}
raw_spin_lock(&pool_lock);
obj = __alloc_object(&obj_pool);
if (obj) {
obj_pool_used++;
obj_pool_free--;
/*
* Looking ahead, allocate one batch of debug objects and
* put them into the percpu free pool.
*/
if (likely(obj_cache)) {
int i;
for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
struct debug_obj *obj2;
obj2 = __alloc_object(&obj_pool);
if (!obj2)
break;
hlist_add_head(&obj2->node,
&percpu_pool->free_objs);
percpu_pool->obj_free++;
obj_pool_used++;
obj_pool_free--;
}
}
if (obj_pool_used > obj_pool_max_used)
obj_pool_max_used = obj_pool_used;
if (obj_pool_free < obj_pool_min_free)
obj_pool_min_free = obj_pool_free;
}
raw_spin_unlock(&pool_lock);
init_obj:
if (obj) {
obj->object = addr;
obj->descr = descr;
obj->state = ODEBUG_STATE_NONE;
obj->astate = 0;
hlist_add_head(&obj->node, &b->list);
}
return obj;
}
/*
* workqueue function to free objects.
*
* To reduce contention on the global pool_lock, the actual freeing of
* debug objects will be delayed if the pool_lock is busy.
*/
static void free_obj_work(struct work_struct *work)
{
struct hlist_node *tmp;
struct debug_obj *obj;
unsigned long flags;
HLIST_HEAD(tofree);
WRITE_ONCE(obj_freeing, false);
if (!raw_spin_trylock_irqsave(&pool_lock, flags))
return;
if (obj_pool_free >= debug_objects_pool_size)
goto free_objs;
/*
* The objs on the pool list might be allocated before the work is
* run, so recheck if pool list it full or not, if not fill pool
* list from the global free list. As it is likely that a workload
* may be gearing up to use more and more objects, don't free any
* of them until the next round.
*/
while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
obj_nr_tofree--;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
return;
free_objs:
/*
* Pool list is already full and there are still objs on the free
* list. Move remaining free objs to a temporary list to free the
* memory outside the pool_lock held region.
*/
if (obj_nr_tofree) {
hlist_move_list(&obj_to_free, &tofree);
debug_objects_freed += obj_nr_tofree;
obj_nr_tofree = 0;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
hlist_del(&obj->node);
kmem_cache_free(obj_cache, obj);
}
}
static void __free_object(struct debug_obj *obj)
{
struct debug_obj *objs[ODEBUG_BATCH_SIZE];
struct debug_percpu_free *percpu_pool;
int lookahead_count = 0;
unsigned long flags;
bool work;
local_irq_save(flags);
if (!obj_cache)
goto free_to_obj_pool;
/*
* Try to free it into the percpu pool first.
*/
percpu_pool = this_cpu_ptr(&percpu_obj_pool);
if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
hlist_add_head(&obj->node, &percpu_pool->free_objs);
percpu_pool->obj_free++;
local_irq_restore(flags);
return;
}
/*
* As the percpu pool is full, look ahead and pull out a batch
* of objects from the percpu pool and free them as well.
*/
for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
if (!objs[lookahead_count])
break;
percpu_pool->obj_free--;
}
free_to_obj_pool:
raw_spin_lock(&pool_lock);
work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
(obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
obj_pool_used--;
if (work) {
obj_nr_tofree++;
hlist_add_head(&obj->node, &obj_to_free);
if (lookahead_count) {
obj_nr_tofree += lookahead_count;
obj_pool_used -= lookahead_count;
while (lookahead_count) {
hlist_add_head(&objs[--lookahead_count]->node,
&obj_to_free);
}
}
if ((obj_pool_free > debug_objects_pool_size) &&
(obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
int i;
/*
* Free one more batch of objects from obj_pool.
*/
for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
obj = __alloc_object(&obj_pool);
hlist_add_head(&obj->node, &obj_to_free);
obj_pool_free--;
obj_nr_tofree++;
}
}
} else {
obj_pool_free++;
hlist_add_head(&obj->node, &obj_pool);
if (lookahead_count) {
obj_pool_free += lookahead_count;
obj_pool_used -= lookahead_count;
while (lookahead_count) {
hlist_add_head(&objs[--lookahead_count]->node,
&obj_pool);
}
}
}
raw_spin_unlock(&pool_lock);
local_irq_restore(flags);
}
/*
* Put the object back into the pool and schedule work to free objects
* if necessary.
*/
static void free_object(struct debug_obj *obj)
{
__free_object(obj);
if (!obj_freeing && obj_nr_tofree) {
WRITE_ONCE(obj_freeing, true);
schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
}
}
/*
* We run out of memory. That means we probably have tons of objects
* allocated.
*/
static void debug_objects_oom(void)
{
struct debug_bucket *db = obj_hash;
struct hlist_node *tmp;
HLIST_HEAD(freelist);
struct debug_obj *obj;
unsigned long flags;
int i;
pr_warn("Out of memory. ODEBUG disabled\n");
for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
raw_spin_lock_irqsave(&db->lock, flags);
hlist_move_list(&db->list, &freelist);
raw_spin_unlock_irqrestore(&db->lock, flags);
/* Now free them */
hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
hlist_del(&obj->node);
free_object(obj);
}
}
}
/*
* We use the pfn of the address for the hash. That way we can check
* for freed objects simply by checking the affected bucket.
*/
static struct debug_bucket *get_bucket(unsigned long addr)
{
unsigned long hash;
hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
return &obj_hash[hash];
}
static void debug_print_object(struct debug_obj *obj, char *msg)
{
struct debug_obj_descr *descr = obj->descr;
static int limit;
if (limit < 5 && descr != descr_test) {
void *hint = descr->debug_hint ?
descr->debug_hint(obj->object) : NULL;
limit++;
WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
"object type: %s hint: %pS\n",
msg, obj_states[obj->state], obj->astate,
descr->name, hint);
}
debug_objects_warnings++;
}
/*
* Try to repair the damage, so we have a better chance to get useful
* debug output.
*/
static bool
debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
void * addr, enum debug_obj_state state)
{
if (fixup && fixup(addr, state)) {
debug_objects_fixups++;
return true;
}
return false;
}
static void debug_object_is_on_stack(void *addr, int onstack)
{
int is_on_stack;
static int limit;
if (limit > 4)
return;
is_on_stack = object_is_on_stack(addr);
if (is_on_stack == onstack)
return;
limit++;
if (is_on_stack)
pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
task_stack_page(current));
else
pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
task_stack_page(current));
WARN_ON(1);
}
static void
__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
{
enum debug_obj_state state;
bool check_stack = false;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
fill_pool();
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj) {
obj = alloc_object(addr, db, descr);
if (!obj) {
debug_objects_enabled = 0;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_objects_oom();
return;
}
check_stack = true;
}
switch (obj->state) {
case ODEBUG_STATE_NONE:
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_INIT;
break;
case ODEBUG_STATE_ACTIVE:
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "init");
debug_object_fixup(descr->fixup_init, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "init");
return;
default:
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (check_stack)
debug_object_is_on_stack(addr, onstack);
}
/**
* debug_object_init - debug checks when an object is initialized
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_init(void *addr, struct debug_obj_descr *descr)
{
if (!debug_objects_enabled)
return;
__debug_object_init(addr, descr, 0);
}
EXPORT_SYMBOL_GPL(debug_object_init);
/**
* debug_object_init_on_stack - debug checks when an object on stack is
* initialized
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
{
if (!debug_objects_enabled)
return;
__debug_object_init(addr, descr, 1);
}
EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
/**
* debug_object_activate - debug checks when an object is activated
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
* Returns 0 for success, -EINVAL for check failed.
*/
int debug_object_activate(void *addr, struct debug_obj_descr *descr)
{
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
int ret;
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
if (!debug_objects_enabled)
return 0;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (obj) {
bool print_object = false;
switch (obj->state) {
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_ACTIVE;
ret = 0;
break;
case ODEBUG_STATE_ACTIVE:
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "activate");
ret = debug_object_fixup(descr->fixup_activate, addr, state);
return ret ? 0 : -EINVAL;
case ODEBUG_STATE_DESTROYED:
print_object = true;
ret = -EINVAL;
break;
default:
ret = 0;
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (print_object)
debug_print_object(obj, "activate");
return ret;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
/*
* We are here when a static object is activated. We
* let the type specific code confirm whether this is
* true or not. if true, we just make sure that the
* static object is tracked in the object tracker. If
* not, this must be a bug, so we try to fix it up.
*/
if (descr->is_static_object && descr->is_static_object(addr)) {
/* track this static object */
debug_object_init(addr, descr);
debug_object_activate(addr, descr);
} else {
debug_print_object(&o, "activate");
ret = debug_object_fixup(descr->fixup_activate, addr,
ODEBUG_STATE_NOTAVAILABLE);
return ret ? 0 : -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(debug_object_activate);
/**
* debug_object_deactivate - debug checks when an object is deactivated
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
{
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
bool print_object = false;
if (!debug_objects_enabled)
return;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (obj) {
switch (obj->state) {
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
case ODEBUG_STATE_ACTIVE:
if (!obj->astate)
obj->state = ODEBUG_STATE_INACTIVE;
else
print_object = true;
break;
case ODEBUG_STATE_DESTROYED:
print_object = true;
break;
default:
break;
}
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (!obj) {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "deactivate");
} else if (print_object) {
debug_print_object(obj, "deactivate");
}
}
EXPORT_SYMBOL_GPL(debug_object_deactivate);
/**
* debug_object_destroy - debug checks when an object is destroyed
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
{
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
bool print_object = false;
if (!debug_objects_enabled)
return;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj)
goto out_unlock;
switch (obj->state) {
case ODEBUG_STATE_NONE:
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_DESTROYED;
break;
case ODEBUG_STATE_ACTIVE:
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "destroy");
debug_object_fixup(descr->fixup_destroy, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
print_object = true;
break;
default:
break;
}
out_unlock:
raw_spin_unlock_irqrestore(&db->lock, flags);
if (print_object)
debug_print_object(obj, "destroy");
}
EXPORT_SYMBOL_GPL(debug_object_destroy);
/**
* debug_object_free - debug checks when an object is freed
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_free(void *addr, struct debug_obj_descr *descr)
{
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
if (!debug_objects_enabled)
return;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj)
goto out_unlock;
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "free");
debug_object_fixup(descr->fixup_free, addr, state);
return;
default:
hlist_del(&obj->node);
raw_spin_unlock_irqrestore(&db->lock, flags);
free_object(obj);
return;
}
out_unlock:
raw_spin_unlock_irqrestore(&db->lock, flags);
}
EXPORT_SYMBOL_GPL(debug_object_free);
/**
* debug_object_assert_init - debug checks when object should be init-ed
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
*/
void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
{
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
if (!debug_objects_enabled)
return;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj) {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
raw_spin_unlock_irqrestore(&db->lock, flags);
/*
* Maybe the object is static, and we let the type specific
* code confirm. Track this static object if true, else invoke
* fixup.
*/
if (descr->is_static_object && descr->is_static_object(addr)) {
/* Track this static object */
debug_object_init(addr, descr);
} else {
debug_print_object(&o, "assert_init");
debug_object_fixup(descr->fixup_assert_init, addr,
ODEBUG_STATE_NOTAVAILABLE);
}
return;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
}
EXPORT_SYMBOL_GPL(debug_object_assert_init);
/**
* debug_object_active_state - debug checks object usage state machine
* @addr: address of the object
* @descr: pointer to an object specific debug description structure
* @expect: expected state
* @next: state to move to if expected state is found
*/
void
debug_object_active_state(void *addr, struct debug_obj_descr *descr,
unsigned int expect, unsigned int next)
{
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
bool print_object = false;
if (!debug_objects_enabled)
return;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (obj) {
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
if (obj->astate == expect)
obj->astate = next;
else
print_object = true;
break;
default:
print_object = true;
break;
}
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (!obj) {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "active_state");
} else if (print_object) {
debug_print_object(obj, "active_state");
}
}
EXPORT_SYMBOL_GPL(debug_object_active_state);
#ifdef CONFIG_DEBUG_OBJECTS_FREE
static void __debug_check_no_obj_freed(const void *address, unsigned long size)
{
unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
struct debug_obj_descr *descr;
enum debug_obj_state state;
struct debug_bucket *db;
struct hlist_node *tmp;
struct debug_obj *obj;
int cnt, objs_checked = 0;
saddr = (unsigned long) address;
eaddr = saddr + size;
paddr = saddr & ODEBUG_CHUNK_MASK;
chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
chunks >>= ODEBUG_CHUNK_SHIFT;
for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
db = get_bucket(paddr);
repeat:
cnt = 0;
raw_spin_lock_irqsave(&db->lock, flags);
hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
cnt++;
oaddr = (unsigned long) obj->object;
if (oaddr < saddr || oaddr >= eaddr)
continue;
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
descr = obj->descr;
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "free");
debug_object_fixup(descr->fixup_free,
(void *) oaddr, state);
goto repeat;
default:
hlist_del(&obj->node);
__free_object(obj);
break;
}
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
objs_checked += cnt;
}
if (objs_checked > debug_objects_maxchecked)
debug_objects_maxchecked = objs_checked;
/* Schedule work to actually kmem_cache_free() objects */
if (!obj_freeing && obj_nr_tofree) {
WRITE_ONCE(obj_freeing, true);
schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
}
}
void debug_check_no_obj_freed(const void *address, unsigned long size)
{
if (debug_objects_enabled)
__debug_check_no_obj_freed(address, size);
}
#endif
#ifdef CONFIG_DEBUG_FS
static int debug_stats_show(struct seq_file *m, void *v)
{
int cpu, obj_percpu_free = 0;
for_each_possible_cpu(cpu)
obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
seq_printf(m, "warnings :%d\n", debug_objects_warnings);
seq_printf(m, "fixups :%d\n", debug_objects_fixups);
seq_printf(m, "pool_free :%d\n", obj_pool_free + obj_percpu_free);
seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
seq_printf(m, "on_free_list :%d\n", obj_nr_tofree);
seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
return 0;
}
static int debug_stats_open(struct inode *inode, struct file *filp)
{
return single_open(filp, debug_stats_show, NULL);
}
static const struct file_operations debug_stats_fops = {
.open = debug_stats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init debug_objects_init_debugfs(void)
{
struct dentry *dbgdir;
if (!debug_objects_enabled)
return 0;
dbgdir = debugfs_create_dir("debug_objects", NULL);
debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
return 0;
}
__initcall(debug_objects_init_debugfs);
#else
static inline void debug_objects_init_debugfs(void) { }
#endif
#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
/* Random data structure for the self test */
struct self_test {
unsigned long dummy1[6];
int static_init;
unsigned long dummy2[3];
};
static __initdata struct debug_obj_descr descr_type_test;
static bool __init is_static_object(void *addr)
{
struct self_test *obj = addr;
return obj->static_init;
}
/*
* fixup_init is called when:
* - an active object is initialized
*/
static bool __init fixup_init(void *addr, enum debug_obj_state state)
{
struct self_test *obj = addr;
switch (state) {
case ODEBUG_STATE_ACTIVE:
debug_object_deactivate(obj, &descr_type_test);
debug_object_init(obj, &descr_type_test);
return true;
default:
return false;
}
}
/*
* fixup_activate is called when:
* - an active object is activated
* - an unknown non-static object is activated
*/
static bool __init fixup_activate(void *addr, enum debug_obj_state state)
{
struct self_test *obj = addr;
switch (state) {
case ODEBUG_STATE_NOTAVAILABLE:
return true;
case ODEBUG_STATE_ACTIVE:
debug_object_deactivate(obj, &descr_type_test);
debug_object_activate(obj, &descr_type_test);
return true;
default:
return false;
}
}
/*
* fixup_destroy is called when:
* - an active object is destroyed
*/
static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
{
struct self_test *obj = addr;
switch (state) {
case ODEBUG_STATE_ACTIVE:
debug_object_deactivate(obj, &descr_type_test);
debug_object_destroy(obj, &descr_type_test);
return true;
default:
return false;
}
}
/*
* fixup_free is called when:
* - an active object is freed
*/
static bool __init fixup_free(void *addr, enum debug_obj_state state)
{
struct self_test *obj = addr;
switch (state) {
case ODEBUG_STATE_ACTIVE:
debug_object_deactivate(obj, &descr_type_test);
debug_object_free(obj, &descr_type_test);
return true;
default:
return false;
}
}
static int __init
check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
{
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
int res = -EINVAL;
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj && state != ODEBUG_STATE_NONE) {
WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
goto out;
}
if (obj && obj->state != state) {
WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
obj->state, state);
goto out;
}
if (fixups != debug_objects_fixups) {
WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
fixups, debug_objects_fixups);
goto out;
}
if (warnings != debug_objects_warnings) {
WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
warnings, debug_objects_warnings);
goto out;
}
res = 0;
out:
raw_spin_unlock_irqrestore(&db->lock, flags);
if (res)
debug_objects_enabled = 0;
return res;
}
static __initdata struct debug_obj_descr descr_type_test = {
.name = "selftest",
.is_static_object = is_static_object,
.fixup_init = fixup_init,
.fixup_activate = fixup_activate,
.fixup_destroy = fixup_destroy,
.fixup_free = fixup_free,
};
static __initdata struct self_test obj = { .static_init = 0 };
static void __init debug_objects_selftest(void)
{
int fixups, oldfixups, warnings, oldwarnings;
unsigned long flags;
local_irq_save(flags);
fixups = oldfixups = debug_objects_fixups;
warnings = oldwarnings = debug_objects_warnings;
descr_test = &descr_type_test;
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
goto out;
debug_object_activate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
goto out;
debug_object_activate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
goto out;
debug_object_deactivate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
goto out;
debug_object_destroy(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
goto out;
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
goto out;
debug_object_activate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
goto out;
debug_object_deactivate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
goto out;
debug_object_free(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
goto out;
obj.static_init = 1;
debug_object_activate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
goto out;
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
goto out;
debug_object_free(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
goto out;
#ifdef CONFIG_DEBUG_OBJECTS_FREE
debug_object_init(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
goto out;
debug_object_activate(&obj, &descr_type_test);
if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
goto out;
__debug_check_no_obj_freed(&obj, sizeof(obj));
if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
goto out;
#endif
pr_info("selftest passed\n");
out:
debug_objects_fixups = oldfixups;
debug_objects_warnings = oldwarnings;
descr_test = NULL;
local_irq_restore(flags);
}
#else
static inline void debug_objects_selftest(void) { }
#endif
/*
* Called during early boot to initialize the hash buckets and link
* the static object pool objects into the poll list. After this call
* the object tracker is fully operational.
*/
void __init debug_objects_early_init(void)
{
int i;
for (i = 0; i < ODEBUG_HASH_SIZE; i++)
raw_spin_lock_init(&obj_hash[i].lock);
for (i = 0; i < ODEBUG_POOL_SIZE; i++)
hlist_add_head(&obj_static_pool[i].node, &obj_pool);
}
/*
* Convert the statically allocated objects to dynamic ones:
*/
static int __init debug_objects_replace_static_objects(void)
{
struct debug_bucket *db = obj_hash;
struct hlist_node *tmp;
struct debug_obj *obj, *new;
HLIST_HEAD(objects);
int i, cnt = 0;
for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
if (!obj)
goto free;
hlist_add_head(&obj->node, &objects);
}
/*
* debug_objects_mem_init() is now called early that only one CPU is up
* and interrupts have been disabled, so it is safe to replace the
* active object references.
*/
/* Remove the statically allocated objects from the pool */
hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
hlist_del(&obj->node);
/* Move the allocated objects to the pool */
hlist_move_list(&objects, &obj_pool);
/* Replace the active object references */
for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
hlist_move_list(&db->list, &objects);
hlist_for_each_entry(obj, &objects, node) {
new = hlist_entry(obj_pool.first, typeof(*obj), node);
hlist_del(&new->node);
/* copy object data */
*new = *obj;
hlist_add_head(&new->node, &db->list);
cnt++;
}
}
pr_debug("%d of %d active objects replaced\n",
cnt, obj_pool_used);
return 0;
free:
hlist_for_each_entry_safe(obj, tmp, &objects, node) {
hlist_del(&obj->node);
kmem_cache_free(obj_cache, obj);
}
return -ENOMEM;
}
/*
* Called after the kmem_caches are functional to setup a dedicated
* cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
* prevents that the debug code is called on kmem_cache_free() for the
* debug tracker objects to avoid recursive calls.
*/
void __init debug_objects_mem_init(void)
{
int cpu, extras;
if (!debug_objects_enabled)
return;
/*
* Initialize the percpu object pools
*
* Initialization is not strictly necessary, but was done for
* completeness.
*/
for_each_possible_cpu(cpu)
INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
obj_cache = kmem_cache_create("debug_objects_cache",
sizeof (struct debug_obj), 0,
SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
NULL);
if (!obj_cache || debug_objects_replace_static_objects()) {
debug_objects_enabled = 0;
kmem_cache_destroy(obj_cache);
pr_warn("out of memory.\n");
} else
debug_objects_selftest();
/*
* Increase the thresholds for allocating and freeing objects
* according to the number of possible CPUs available in the system.
*/
extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
debug_objects_pool_size += extras;
debug_objects_pool_min_level += extras;
}