diff --git a/repos/base/src/lib/base/lock.cc b/repos/base/src/lib/base/lock.cc
index 447062ee7e..b358496304 100644
--- a/repos/base/src/lib/base/lock.cc
+++ b/repos/base/src/lib/base/lock.cc
@@ -146,12 +146,16 @@ void Cancelable_lock::unlock()
 
 		/* transfer lock ownership to next applicant and wake him up */
 		_owner = *next_owner;
+
+		/* make copy since _owner may change outside spinlock ! */
+		Applicant owner = *next_owner;
+
 		if (_last_applicant == next_owner)
 			_last_applicant = &_owner;
 
 		spinlock_unlock(&_spinlock_state);
 
-		_owner.wake_up();
+		owner.wake_up();
 
 	} else {