From c99729093af33b97b190eed8da84dd28ee61b25f Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Date: Fri, 7 Oct 2016 19:59:18 +0200
Subject: [PATCH] base: fix race in multiple lock.unlock() calls

Fixes #2122
---
 repos/base/src/lib/base/lock.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

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 {