[patch] lockdep: fix possible race while disabling lock-debugging, restore fix

[Ingo Molnar <mingo@elte.hu>]

* Jarek Poplawski <jarkao2@o2.pl> wrote:

> ...
> > @@ -1212,7 +1244,8 @@ register_lock_class(struct lockdep_map *
> >  	hash_head = classhashentry(key);
> >  
> >  	raw_local_irq_save(flags);
> > -	__raw_spin_lock(&hash_lock);
> > +	if (!graph_lock())
> 
> 	! raw_local_irq_restore(flags);
> 
> > +		return NULL;

yeah. Fix below.

	Ingo

Subject: [patch] lockdep: fix possible race while disabling lock-debugging, restore fix
From: Ingo Molnar <mingo@elte.hu>

restore flags in failure branch, pointed out by Jarek Poplawski.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/lockdep.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux/kernel/lockdep.c
===================================================================
--- linux.orig/kernel/lockdep.c
+++ linux/kernel/lockdep.c
@@ -1244,8 +1244,10 @@ register_lock_class(struct lockdep_map *
 	hash_head = classhashentry(key);
 
 	raw_local_irq_save(flags);
-	if (!graph_lock())
+	if (!graph_lock()) {
+		raw_local_irq_restore(flags);
 		return NULL;
+	}
 	/*
 	 * We have to do the hash-walk again, to avoid races
 	 * with another CPU: