From oneukum@suse.de Mon Apr 2 06:24:01 2007 From: Oliver Neukum Date: Mon, 2 Apr 2007 14:47:59 +0200 Subject: kref: fix CPU ordering with respect to krefs To: Greg KH , linux-kernel@vger.kernel.org Message-ID: <200704021447.59476.oneukum@suse.de> Content-Disposition: inline some atomic operations are only atomic, not ordered. Thus a CPU is allowed to reorder memory references to an object to before the reference is obtained. This fixes it. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- lib/kref.c | 2 ++ 1 file changed, 2 insertions(+) --- a/lib/kref.c +++ b/lib/kref.c @@ -21,6 +21,7 @@ void kref_init(struct kref *kref) { atomic_set(&kref->refcount,1); + smp_mb(); } /** @@ -31,6 +32,7 @@ void kref_get(struct kref *kref) { WARN_ON(!atomic_read(&kref->refcount)); atomic_inc(&kref->refcount); + smp_mb__after_atomic_inc(); } /**