// SPDX-License-Identifier: GPL-2.0
/*
* Generic infrastructure for lifetime debugging of objects.
*
* Copyright (C) 2008, Thomas Gleixner <[email protected]>
*/
#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>
#include <linux/cpu.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 __data_racy obj_pool_min_free = ODEBUG_POOL_SIZE;
static int __data_racy obj_pool_free = ODEBUG_POOL_SIZE;
static int obj_pool_used;
static int __data_racy obj_pool_max_used;
static bool obj_freeing;
/* The number of objs on the global free list */
static int obj_nr_tofree;
static int __data_racy debug_objects_maxchain __read_mostly;
static int __data_racy __maybe_unused debug_objects_maxchecked __read_mostly;
static int __data_racy debug_objects_fixups __read_mostly;
static int __data_racy debug_objects_warnings __read_mostly;
static int __data_racy debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
static int debug_objects_pool_size __ro_after_init
= ODEBUG_POOL_SIZE;
static int debug_objects_pool_min_level __ro_after_init
= ODEBUG_POOL_MIN_LEVEL;
static const struct debug_obj_descr *descr_test __read_mostly;
static struct kmem_cache *obj_cache __ro_after_init;
/*
* Track numbers of kmem_cache_alloc()/free() calls done.
*/
static int __data_racy debug_objects_allocated;
static int __data_racy 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_HIGH | __GFP_NOWARN;
struct debug_obj *obj;
unsigned long flags;
if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
return;
/*
* Reuse objs from the global obj_to_free list; they will be
* reinitialized when allocating.
*
* obj_nr_tofree is checked locklessly; the READ_ONCE() pairs with
* the WRITE_ONCE() in pool_lock critical sections.
*/
if (READ_ONCE(obj_nr_tofree)) {
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 < debug_objects_pool_min_level)) {
obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
hlist_del(&obj->node);
WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
hlist_add_head(&obj->node, &obj_pool);
WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
if (unlikely(!obj_cache))
return;
while (READ_ONCE(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++;
WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
}
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;
}
static struct debug_obj *
alloc_object(void *addr, struct debug_bucket *b, const 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++;
WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
/*
* 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++;
WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
}
}
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);
WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
}
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;
WRITE_ONCE(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) {
WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
hlist_add_head(&obj->node, &obj_to_free);
if (lookahead_count) {
WRITE_ONCE(obj_nr_tofree, 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);
WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
}
}
} else {
WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
hlist_add_head(&obj->node, &obj_pool);
if (lookahead_count) {
WRITE_ONCE(obj_pool_free, 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 (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
WRITE_ONCE(obj_freeing, true);
schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
}
}
#ifdef CONFIG_HOTPLUG_CPU
static int object_cpu_offline(unsigned int cpu)
{
struct debug_percpu_free *percpu_pool;
struct hlist_node *tmp;
struct debug_obj *obj;
unsigned long flags;
/* Remote access is safe as the CPU is dead already */
percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
hlist_del(&obj->node);
kmem_cache_free(obj_cache, obj);
}
raw_spin_lock_irqsave(&pool_lock, flags);
obj_pool_used -= percpu_pool->obj_free;
debug_objects_freed += percpu_pool->obj_free;
raw_spin_unlock_irqrestore(&pool_lock, flags);
percpu_pool->obj_free = 0;
return 0;
}
#endif
/*
* 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)
{
const struct debug_obj_descr *descr = obj->descr;
static int limit;
/*
* Don't report if lookup_object_or_alloc() by the current thread
* failed because lookup_object_or_alloc()/debug_objects_oom() by a
* concurrent thread turned off debug_objects_enabled and cleared
* the hash buckets.
*/
if (!debug_objects_enabled)
return;
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: %p object type: %s hint: %pS\n",
msg, obj_states[obj->state], obj->astate,
obj->object, 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 struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
const struct debug_obj_descr *descr,
bool onstack, bool alloc_ifstatic)
{
struct debug_obj *obj = lookup_object(addr, b);
enum debug_obj_state state = ODEBUG_STATE_NONE;
if (likely(obj))
return obj;
/*
* debug_object_init() unconditionally allocates untracked
* objects. It does not matter whether it is a static object or
* not.
*
* debug_object_assert_init() and debug_object_activate() allow
* allocation only if the descriptor callback confirms that the
* object is static and considered initialized. For non-static
* objects the allocation needs to be done from the fixup callback.
*/
if (unlikely(alloc_ifstatic)) {
if (!descr->is_static_object || !descr->is_static_object(addr))
return ERR_PTR(-ENOENT);
/* Statically allocated objects are considered initialized */
state = ODEBUG_STATE_INIT;
}
obj = alloc_object(addr, b, descr);
if (likely(obj)) {
obj->state = state;
debug_object_is_on_stack(addr, onstack);
return obj;
}
/* Out of memory. Do the cleanup outside of the locked region */
debug_objects_enabled = 0;
return NULL;
}
static void debug_objects_fill_pool(void)
{
/*
* On RT enabled kernels the pool refill must happen in preemptible
* context -- for !RT kernels we rely on the fact that spinlock_t and
* raw_spinlock_t are basically the same type and this lock-type
* inversion works just fine.
*/
if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
/*
* Annotate away the spinlock_t inside raw_spinlock_t warning
* by temporarily raising the wait-type to WAIT_SLEEP, matching
* the preemptible() condition above.
*/
static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
lock_map_acquire_try(&fill_pool_map);
fill_pool();
lock_map_release(&fill_pool_map);
}
}
static void
__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
{
struct debug_obj *obj, o;
struct debug_bucket *db;
unsigned long flags;
debug_objects_fill_pool();
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
if (unlikely(!obj)) {
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_objects_oom();
return;
}
switch (obj->state) {
case ODEBUG_STATE_NONE:
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_INIT;
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
default:
break;
}
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "init");
if (o.state == ODEBUG_STATE_ACTIVE)
debug_object_fixup(descr->fixup_init, addr, o.state);
}
/**
* 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, const 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, const 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, const struct debug_obj_descr *descr)
{
struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
if (!debug_objects_enabled)
return 0;
debug_objects_fill_pool();
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object_or_alloc(addr, db, descr, false, true);
if (unlikely(!obj)) {
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_objects_oom();
return 0;
} else if (likely(!IS_ERR(obj))) {
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
case ODEBUG_STATE_DESTROYED:
o = *obj;
break;
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_ACTIVE;
fallthrough;
default:
raw_spin_unlock_irqrestore(&db->lock, flags);
return 0;
}
}
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "activate");
switch (o.state) {
case ODEBUG_STATE_ACTIVE:
case ODEBUG_STATE_NOTAVAILABLE:
if (debug_object_fixup(descr->fixup_activate, addr, o.state))
return 0;
fallthrough;
default:
return -EINVAL;
}
}
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, const struct debug_obj_descr *descr)
{
struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .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) {
switch (obj->state) {
case ODEBUG_STATE_DESTROYED:
break;
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
case ODEBUG_STATE_ACTIVE:
if (obj->astate)
break;
obj->state = ODEBUG_STATE_INACTIVE;
fallthrough;
default:
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
o = *obj;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "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, const struct debug_obj_descr *descr)
{
struct debug_obj *obj, o;
struct debug_bucket *db;
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) {
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
case ODEBUG_STATE_DESTROYED:
break;
case ODEBUG_STATE_NONE:
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_DESTROYED;
fallthrough;
default:
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "destroy");
if (o.state == ODEBUG_STATE_ACTIVE)
debug_object_fixup(descr->fixup_destroy, addr, o.state);
}
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, const struct debug_obj_descr *descr)
{
struct debug_obj *obj, o;
struct debug_bucket *db;
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) {
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
break;
default:
hlist_del(&obj->node);
raw_spin_unlock_irqrestore(&db->lock, flags);
free_object(obj);
return;
}
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "free");
debug_object_fixup(descr->fixup_free, addr, o.state);
}
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, const struct debug_obj_descr *descr)
{
struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
if (!debug_objects_enabled)
return;
debug_objects_fill_pool();
db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object_or_alloc(addr, db, descr, false, true);
raw_spin_unlock_irqrestore(&db->lock, flags);
if (likely(!IS_ERR_OR_NULL(obj)))
return;
/* If NULL the allocation has hit OOM */
if (!obj) {
debug_objects_oom();
return;
}
/* Object is neither tracked nor static. It's not initialized. */
debug_print_object(&o, "assert_init");
debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
}
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, const struct debug_obj_descr *descr,
unsigned int expect, unsigned int next)
{
struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .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) {
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
if (obj->astate != expect)
break;
obj->astate = next;
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
default:
break;
}
o = *obj;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "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;
int cnt, objs_checked = 0;
struct debug_obj *obj, o;
struct debug_bucket *db;
struct hlist_node *tmp;
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:
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(&o, "free");
debug_object_fixup(o.descr->fixup_free, (void *)oaddr, o.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 (!READ_ONCE(obj_freeing) && READ_ONCE(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", READ_ONCE(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", READ_ONCE(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;
}
DEFINE_SHOW_ATTRIBUTE(debug_stats);
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 __initconst const 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 __initconst const 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_allocated += i;
/*
* 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");
return;
} else
debug_objects_selftest();
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
object_cpu_offline);
#endif
/*
* 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;
}
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