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Subject[PATCH] lockdep: returns after DEBUG_LOCKS_WARN_ONs etc.
Hello,

If any of this proposals should be omitted or separated
let me know.

Regards,
Jarek P.

---
[PATCH] lockdep: returns after DEBUG_LOCKS_WARN_ONs etc.

lockdep.c changes:

- returns after DEBUG_LOCKS_WARN_ON added in 3 places

- debug_locks checking after lookup_chain_cache()
added in __lock_acquire()

- locking for testing and changing global variable
max_lockdep_depth added in __lock_acquire()

- local_irq_save/restore() replaced by raw versions
in debug_check_no_locks_freed()

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
---

diff -Nurp linux-2.6.20-rc1-/kernel/lockdep.c linux-2.6.20-rc1/kernel/lockdep.c
--- linux-2.6.20-rc1-/kernel/lockdep.c 2006-12-18 08:59:24.000000000 +0100
+++ linux-2.6.20-rc1/kernel/lockdep.c 2006-12-18 11:57:40.000000000 +0100
@@ -1293,7 +1293,8 @@ out_unlock_set:
if (!subclass || force)
lock->class_cache = class;

- DEBUG_LOCKS_WARN_ON(class->subclass != subclass);
+ if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+ return NULL;

return class;
}
@@ -1308,7 +1309,8 @@ static inline int lookup_chain_cache(u64
struct list_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;

- DEBUG_LOCKS_WARN_ON(!irqs_disabled());
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
/*
* We can walk it lock-free, because entries only get added
* to the hash:
@@ -1390,7 +1392,9 @@ static void check_chain_key(struct task_
return;
}
id = hlock->class - lock_classes;
- DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS);
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return;
+
if (prev_hlock && (prev_hlock->irq_context !=
hlock->irq_context))
chain_key = 0;
@@ -2201,7 +2205,11 @@ out_calc_hash:
if (!check_prevs_add(curr, hlock))
return 0;
graph_unlock();
- }
+
+ } else if (unlikely(!debug_locks))
+ /* after lookup_chain_cache() */
+ return 0;
+
curr->lockdep_depth++;
check_chain_key(curr);
if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
@@ -2210,9 +2218,14 @@ out_calc_hash:
printk("turning off the locking correctness validator.\n");
return 0;
}
+
+ if (!graph_lock())
+ return 0;
+
if (unlikely(curr->lockdep_depth > max_lockdep_depth))
max_lockdep_depth = curr->lockdep_depth;

+ graph_unlock();
return 1;
}

@@ -2665,7 +2678,7 @@ void debug_check_no_locks_freed(const vo
if (unlikely(!debug_locks))
return;

- local_irq_save(flags);
+ raw_local_irq_save(flags);
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;

@@ -2679,7 +2692,7 @@ void debug_check_no_locks_freed(const vo
print_freed_lock_bug(curr, mem_from, mem_to, hlock);
break;
}
- local_irq_restore(flags);
+ raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);

-
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