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Subject[GIT pull] debugobject fixes for 2.6.27
Linus,

Please pull the latest core/debugobjects git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core/debugobjects

It contains a lockdep fix for the debug objects core code. Please note
that I added a helper function to move a hlist from one head to
another to avoid open coding it in the debugobjects code.

Thanks,

tglx

------------------>
Vegard Nossum (1):
debugobjects: fix lockdep warning

include/linux/list.h | 13 +++++++++++++
lib/debugobjects.c | 31 +++++++++++++++++++++++--------
2 files changed, 36 insertions(+), 8 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index db35ef0..969f6e9 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -619,6 +619,19 @@ static inline void hlist_add_after(struct hlist_node *n,
next->next->pprev = &next->next;
}

+/*
+ * Move a list from one list head to another. Fixup the pprev
+ * reference of the first entry if it exists.
+ */
+static inline void hlist_move_list(struct hlist_head *old,
+ struct hlist_head *new)
+{
+ new->first = old->first;
+ if (new->first)
+ new->first->pprev = &new->first;
+ old->first = NULL;
+}
+
#define hlist_entry(ptr, type, member) container_of(ptr,type,member)

#define hlist_for_each(pos, head) \
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 45a6bde..e3ab374 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -112,6 +112,7 @@ static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)

/*
* 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)
@@ -148,17 +149,18 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
static void free_object(struct debug_obj *obj)
{
unsigned long idx = (unsigned long)(obj - obj_static_pool);
+ unsigned long flags;

if (obj_pool_free < ODEBUG_POOL_SIZE || idx < ODEBUG_POOL_SIZE) {
- spin_lock(&pool_lock);
+ spin_lock_irqsave(&pool_lock, flags);
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
obj_pool_used--;
- spin_unlock(&pool_lock);
+ spin_unlock_irqrestore(&pool_lock, flags);
} else {
- spin_lock(&pool_lock);
+ spin_lock_irqsave(&pool_lock, flags);
obj_pool_used--;
- spin_unlock(&pool_lock);
+ spin_unlock_irqrestore(&pool_lock, flags);
kmem_cache_free(obj_cache, obj);
}
}
@@ -171,6 +173,7 @@ static void debug_objects_oom(void)
{
struct debug_bucket *db = obj_hash;
struct hlist_node *node, *tmp;
+ HLIST_HEAD(freelist);
struct debug_obj *obj;
unsigned long flags;
int i;
@@ -179,11 +182,14 @@ static void debug_objects_oom(void)

for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
spin_lock_irqsave(&db->lock, flags);
- hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
+ hlist_move_list(&db->list, &freelist);
+ spin_unlock_irqrestore(&db->lock, flags);
+
+ /* Now free them */
+ hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
hlist_del(&obj->node);
free_object(obj);
}
- spin_unlock_irqrestore(&db->lock, flags);
}
}

@@ -498,8 +504,9 @@ void debug_object_free(void *addr, struct debug_obj_descr *descr)
return;
default:
hlist_del(&obj->node);
+ spin_unlock_irqrestore(&db->lock, flags);
free_object(obj);
- break;
+ return;
}
out_unlock:
spin_unlock_irqrestore(&db->lock, flags);
@@ -510,6 +517,7 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size)
{
unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
struct hlist_node *node, *tmp;
+ HLIST_HEAD(freelist);
struct debug_obj_descr *descr;
enum debug_obj_state state;
struct debug_bucket *db;
@@ -545,11 +553,18 @@ repeat:
goto repeat;
default:
hlist_del(&obj->node);
- free_object(obj);
+ hlist_add_head(&obj->node, &freelist);
break;
}
}
spin_unlock_irqrestore(&db->lock, flags);
+
+ /* Now free them */
+ hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
+ hlist_del(&obj->node);
+ free_object(obj);
+ }
+
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
}

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