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Subject[patch 1/5] Debugobjects transition check
Implement a basic state machine checker in the debugobjects.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: David S. Miller <davem@davemloft.net>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: akpm@linux-foundation.org
CC: mingo@elte.hu
CC: laijs@cn.fujitsu.com
CC: dipankar@in.ibm.com
CC: josh@joshtriplett.org
CC: dvhltc@us.ibm.com
CC: niv@us.ibm.com
CC: tglx@linutronix.de
CC: peterz@infradead.org
CC: rostedt@goodmis.org
CC: Valdis.Kletnieks@vt.edu
CC: dhowells@redhat.com
CC: eric.dumazet@gmail.com
CC: Alexey Dobriyan <adobriyan@gmail.com>
---
include/linux/debugobjects.h | 11 ++++++++
lib/debugobjects.c | 59 ++++++++++++++++++++++++++++++++++++++++---
2 files changed, 67 insertions(+), 3 deletions(-)

Index: linux.trees.git/include/linux/debugobjects.h
===================================================================
--- linux.trees.git.orig/include/linux/debugobjects.h 2010-03-27 18:48:23.000000000 -0400
+++ linux.trees.git/include/linux/debugobjects.h 2010-03-27 18:50:09.000000000 -0400
@@ -20,12 +20,14 @@ struct debug_obj_descr;
* struct debug_obj - representaion of an tracked object
* @node: hlist node to link the object into the tracker list
* @state: tracked object state
+ * @astate: current active state
* @object: pointer to the real object
* @descr: pointer to an object type specific debug description structure
*/
struct debug_obj {
struct hlist_node node;
enum debug_obj_state state;
+ unsigned int astate;
void *object;
struct debug_obj_descr *descr;
};
@@ -60,6 +62,15 @@ extern void debug_object_deactivate(void
extern void debug_object_destroy (void *addr, struct debug_obj_descr *descr);
extern void debug_object_free (void *addr, struct debug_obj_descr *descr);

+/*
+ * Active state:
+ * - Set at 0 upon initialization.
+ * - Must return to 0 before deactivation.
+ */
+extern void
+debug_object_active_state(void *addr, struct debug_obj_descr *descr,
+ unsigned int expect, unsigned int next);
+
extern void debug_objects_early_init(void);
extern void debug_objects_mem_init(void);
#else
Index: linux.trees.git/lib/debugobjects.c
===================================================================
--- linux.trees.git.orig/lib/debugobjects.c 2010-03-27 18:48:23.000000000 -0400
+++ linux.trees.git/lib/debugobjects.c 2010-03-27 18:50:09.000000000 -0400
@@ -140,6 +140,7 @@ alloc_object(void *addr, struct debug_bu
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);
@@ -251,8 +252,10 @@ static void debug_print_object(struct de

if (limit < 5 && obj->descr != descr_test) {
limit++;
- WARN(1, KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
- obj_states[obj->state], obj->descr->name);
+ WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
+ "object type: %s\n",
+ msg, obj_states[obj->state], obj->astate,
+ obj->descr->name);
}
debug_objects_warnings++;
}
@@ -446,7 +449,10 @@ void debug_object_deactivate(void *addr,
case ODEBUG_STATE_INIT:
case ODEBUG_STATE_INACTIVE:
case ODEBUG_STATE_ACTIVE:
- obj->state = ODEBUG_STATE_INACTIVE;
+ if (!obj->astate)
+ obj->state = ODEBUG_STATE_INACTIVE;
+ else
+ debug_print_object(obj, "deactivate");
break;

case ODEBUG_STATE_DESTROYED:
@@ -552,6 +558,53 @@ out_unlock:
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)
{
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68


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