linux/lib/debugobjects.c
Du, Changbin b9fdac7f66 debugobjects: insulate non-fixup logic related to static obj from fixup callbacks
When activating a static object we need make sure that the object is
tracked in the object tracker.  If it is a non-static object then the
activation is illegal.

In previous implementation, each subsystem need take care of this in
their fixup callbacks.  Actually we can put it into debugobjects core.
Thus we can save duplicated code, and have *pure* fixup callbacks.

To achieve this, a new callback "is_static_object" is introduced to let
the type specific code decide whether a object is static or not.  If
yes, we take it into object tracker, otherwise give warning and invoke
fixup callback.

This change has paassed debugobjects selftest, and I also do some test
with all debugobjects supports enabled.

At last, I have a concern about the fixups that can it change the object
which is in incorrect state on fixup? Because the 'addr' may not point
to any valid object if a non-static object is not tracked.  Then Change
such object can overwrite someone's memory and cause unexpected
behaviour.  For example, the timer_fixup_activate bind timer to function
stub_timer.

Link: http://lkml.kernel.org/r/1462576157-14539-1-git-send-email-changbin.du@intel.com
[changbin.du@intel.com: improve code comments where invoke the new is_static_object callback]
  Link: http://lkml.kernel.org/r/1462777431-8171-1-git-send-email-changbin.du@intel.com
Signed-off-by: Du, Changbin <changbin.du@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Triplett <josh@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00

1112 lines
27 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/seq_file.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/hash.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_CHUNK_SHIFT PAGE_SHIFT
#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
struct debug_bucket {
struct hlist_head list;
raw_spinlock_t lock;
};
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 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 struct kmem_cache *obj_cache;
static int debug_objects_maxchain __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 struct debug_obj_descr *descr_test __read_mostly;
static void free_obj_work(struct work_struct *work);
static DECLARE_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 *new;
unsigned long flags;
if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
return;
if (unlikely(!obj_cache))
return;
while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
new = kmem_cache_zalloc(obj_cache, gfp);
if (!new)
return;
raw_spin_lock_irqsave(&pool_lock, flags);
hlist_add_head(&new->node, &obj_pool);
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. 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_obj *obj = NULL;
raw_spin_lock(&pool_lock);
if (obj_pool.first) {
obj = hlist_entry(obj_pool.first, typeof(*obj), node);
obj->object = addr;
obj->descr = descr;
obj->state = ODEBUG_STATE_NONE;
obj->astate = 0;
hlist_del(&obj->node);
hlist_add_head(&obj->node, &b->list);
obj_pool_used++;
if (obj_pool_used > obj_pool_max_used)
obj_pool_max_used = obj_pool_used;
obj_pool_free--;
if (obj_pool_free < obj_pool_min_free)
obj_pool_min_free = obj_pool_free;
}
raw_spin_unlock(&pool_lock);
return obj;
}
/*
* workqueue function to free objects.
*/
static void free_obj_work(struct work_struct *work)
{
struct debug_obj *obj;
unsigned long flags;
raw_spin_lock_irqsave(&pool_lock, flags);
while (obj_pool_free > ODEBUG_POOL_SIZE) {
obj = hlist_entry(obj_pool.first, typeof(*obj), node);
hlist_del(&obj->node);
obj_pool_free--;
/*
* We release pool_lock across kmem_cache_free() to
* avoid contention on pool_lock.
*/
raw_spin_unlock_irqrestore(&pool_lock, flags);
kmem_cache_free(obj_cache, obj);
raw_spin_lock_irqsave(&pool_lock, flags);
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
/*
* Put the object back into the pool and schedule work to free objects
* if necessary.
*/
static void free_object(struct debug_obj *obj)
{
unsigned long flags;
int sched = 0;
raw_spin_lock_irqsave(&pool_lock, flags);
/*
* schedule work when the pool is filled and the cache is
* initialized:
*/
if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
sched = keventd_up();
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
obj_pool_used--;
raw_spin_unlock_irqrestore(&pool_lock, flags);
if (sched)
schedule_work(&debug_obj_work);
}
/*
* 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 is on stack, but not annotated\n");
else
pr_warn("object is not on stack, but annotated\n");
WARN_ON(1);
}
static void
__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
{
enum debug_obj_state state;
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;
}
debug_object_is_on_stack(addr, onstack);
}
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:
debug_print_object(obj, "init");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_object_fixup(descr->fixup_init, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
debug_print_object(obj, "init");
break;
default:
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
}
/**
* 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);
}
/**
* 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);
}
/**
* 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) {
switch (obj->state) {
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
obj->state = ODEBUG_STATE_ACTIVE;
ret = 0;
break;
case ODEBUG_STATE_ACTIVE:
debug_print_object(obj, "activate");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
ret = debug_object_fixup(descr->fixup_activate, addr, state);
return ret ? 0 : -EINVAL;
case ODEBUG_STATE_DESTROYED:
debug_print_object(obj, "activate");
ret = -EINVAL;
break;
default:
ret = 0;
break;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
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;
}
/**
* 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;
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
debug_print_object(obj, "deactivate");
break;
case ODEBUG_STATE_DESTROYED:
debug_print_object(obj, "deactivate");
break;
default:
break;
}
} else {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "deactivate");
}
raw_spin_unlock_irqrestore(&db->lock, flags);
}
/**
* 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;
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:
debug_print_object(obj, "destroy");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_object_fixup(descr->fixup_destroy, addr, state);
return;
case ODEBUG_STATE_DESTROYED:
debug_print_object(obj, "destroy");
break;
default:
break;
}
out_unlock:
raw_spin_unlock_irqrestore(&db->lock, flags);
}
/**
* 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:
debug_print_object(obj, "free");
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
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);
}
/**
* 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);
}
/**
* 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;
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
debug_print_object(obj, "active_state");
break;
default:
debug_print_object(obj, "active_state");
break;
}
} else {
struct debug_obj o = { .object = addr,
.state = ODEBUG_STATE_NOTAVAILABLE,
.descr = descr };
debug_print_object(&o, "active_state");
}
raw_spin_unlock_irqrestore(&db->lock, flags);
}
#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 hlist_node *tmp;
HLIST_HEAD(freelist);
struct debug_obj_descr *descr;
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
int cnt;
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:
debug_print_object(obj, "free");
descr = obj->descr;
state = obj->state;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_object_fixup(descr->fixup_free,
(void *) oaddr, state);
goto repeat;
default:
hlist_del(&obj->node);
hlist_add_head(&obj->node, &freelist);
break;
}
}
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);
}
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
}
}
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)
{
seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
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);
seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
seq_printf(m, "pool_used :%d\n", obj_pool_used);
seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
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, *dbgstats;
if (!debug_objects_enabled)
return 0;
dbgdir = debugfs_create_dir("debug_objects", NULL);
if (!dbgdir)
return -ENOMEM;
dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
&debug_stats_fops);
if (!dbgstats)
goto err;
return 0;
err:
debugfs_remove(dbgdir);
return -ENOMEM;
}
__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);
}
/*
* When debug_objects_mem_init() is called we know that only
* one CPU is up, so disabling interrupts is enough
* protection. This avoids the lockdep hell of lock ordering.
*/
local_irq_disable();
/* 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++;
}
}
local_irq_enable();
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)
{
if (!debug_objects_enabled)
return;
obj_cache = kmem_cache_create("debug_objects_cache",
sizeof (struct debug_obj), 0,
SLAB_DEBUG_OBJECTS, NULL);
if (!obj_cache || debug_objects_replace_static_objects()) {
debug_objects_enabled = 0;
if (obj_cache)
kmem_cache_destroy(obj_cache);
pr_warn("out of memory.\n");
} else
debug_objects_selftest();
}