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Debugobject changes for v6.8:

Browse Source 
- Make tracking object use more robust: it's not safe to access a
    tracking object after releasing the hashbucket lock. Create a
    persistent copy for debug printouts instead.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-debugobjects-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull debugobject update from Ingo Molnar:

 - Make tracking object use more robust: it's not safe to access a
   tracking object after releasing the hashbucket lock. Create a
   persistent copy for debug printouts instead.

* tag 'core-debugobjects-2024-01-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  debugobjects: Stop accessing objects after releasing hash bucket lock
This commit is contained in:
Linus Torvalds 2024-01-08 18:35:33 -08:00
commit ab9517fa9a
1 changed files with 80 additions and 124 deletions
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204
lib/debugobjects.c
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@ -620,9 +620,8 @@ static void debug_objects_fill_pool(void)
static void
__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
{
enum debug_obj_state state;
struct debug_obj *obj, o;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
debug_objects_fill_pool();
@ -643,24 +642,18 @@ __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack
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;
}
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);
}
/**
@ -701,11 +694,9 @@ EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
{
struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
int ret;
if (!debug_objects_enabled)
return 0;
@ -717,49 +708,38 @@ int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object_or_alloc(addr, db, descr, false, true);
if (likely(!IS_ERR_OR_NULL(obj))) {
bool print_object = false;
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;
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;
fallthrough;
default:
ret = 0;
break;
raw_spin_unlock_irqrestore(&db->lock, flags);
return 0;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
if (print_object)
debug_print_object(obj, "activate");
return ret;
}
raw_spin_unlock_irqrestore(&db->lock, flags);
/* If NULL the allocation has hit OOM */
if (!obj) {
debug_objects_oom();
return 0;
}
/* Object is neither static nor tracked. It's not initialized */
debug_print_object(&o, "activate");
ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
return ret ? 0 : -EINVAL;
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);
@ -770,10 +750,10 @@ EXPORT_SYMBOL_GPL(debug_object_activate);
*/
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;
bool print_object = false;
if (!debug_objects_enabled)
return;
@ -785,33 +765,24 @@ void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
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)
obj->state = ODEBUG_STATE_INACTIVE;
else
print_object = true;
break;
case ODEBUG_STATE_DESTROYED:
print_object = true;
break;
if (obj->astate)
break;
obj->state = ODEBUG_STATE_INACTIVE;
fallthrough;
default:
break;
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
o = *obj;
}
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");
}
debug_print_object(&o, "deactivate");
}
EXPORT_SYMBOL_GPL(debug_object_deactivate);
@ -822,11 +793,9 @@ EXPORT_SYMBOL_GPL(debug_object_deactivate);
*/
void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
{
enum debug_obj_state state;
struct debug_obj *obj, o;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
bool print_object = false;
if (!debug_objects_enabled)
return;
@ -836,32 +805,31 @@ void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj)
goto out_unlock;
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;
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;
fallthrough;
default:
break;
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
out_unlock:
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
if (print_object)
debug_print_object(obj, "destroy");
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);
@ -872,9 +840,8 @@ EXPORT_SYMBOL_GPL(debug_object_destroy);
*/
void debug_object_free(void *addr, const struct debug_obj_descr *descr)
{
enum debug_obj_state state;
struct debug_obj *obj, o;
struct debug_bucket *db;
struct debug_obj *obj;
unsigned long flags;
if (!debug_objects_enabled)
@ -885,24 +852,26 @@ void debug_object_free(void *addr, const struct debug_obj_descr *descr)
raw_spin_lock_irqsave(&db->lock, flags);
obj = lookup_object(addr, db);
if (!obj)
goto out_unlock;
if (!obj) {
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
}
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;
break;
default:
hlist_del(&obj->node);
raw_spin_unlock_irqrestore(&db->lock, flags);
free_object(obj);
return;
}
out_unlock:
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);
@ -954,10 +923,10 @@ 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;
bool print_object = false;
if (!debug_objects_enabled)
return;
@ -970,28 +939,19 @@ debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
if (obj) {
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
if (obj->astate == expect)
obj->astate = next;
else
print_object = true;
break;
if (obj->astate != expect)
break;
obj->astate = next;
raw_spin_unlock_irqrestore(&db->lock, flags);
return;
default:
print_object = true;
break;
}
o = *obj;
}
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");
}
debug_print_object(&o, "active_state");
}
EXPORT_SYMBOL_GPL(debug_object_active_state);
@ -999,12 +959,10 @@ EXPORT_SYMBOL_GPL(debug_object_active_state);
static void __debug_check_no_obj_freed(const void *address, unsigned long size)
{
unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
const struct debug_obj_descr *descr;
enum debug_obj_state state;
int cnt, objs_checked = 0;
struct debug_obj *obj, o;
struct debug_bucket *db;
struct hlist_node *tmp;
struct debug_obj *obj;
int cnt, objs_checked = 0;
saddr = (unsigned long) address;
eaddr = saddr + size;
@ -1026,12 +984,10 @@ repeat:
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
descr = obj->descr;
state = obj->state;
o = *obj;
raw_spin_unlock_irqrestore(&db->lock, flags);
debug_print_object(obj, "free");
debug_object_fixup(descr->fixup_free,
(void *) oaddr, state);
debug_print_object(&o, "free");
debug_object_fixup(o.descr->fixup_free, (void *)oaddr, o.state);
goto repeat;
default:
hlist_del(&obj->node);