From 223506145988c88424a94f7264dabebaf35d8f2d Mon Sep 17 00:00:00 2001
From: scott snyder <sss@karma>
Date: Sun, 3 Oct 2021 14:05:56 -0400
Subject: [PATCH] GeoModelKernel: Fix race in RCBase::unref().
The decrement and test must be done atomically; otherwise we could have
a race. E.g., suppose a RCBase object has a refcount of 2, and two threads
call unref simultaneously. The two decrements could both happen before
either of the comparisons, resulting in a double-delete.
---
GeoModelCore/GeoModelKernel/src/RCBase.cxx | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/GeoModelCore/GeoModelKernel/src/RCBase.cxx b/GeoModelCore/GeoModelKernel/src/RCBase.cxx
index 1fedd9386..368cf3679 100755
--- a/GeoModelCore/GeoModelKernel/src/RCBase.cxx
+++ b/GeoModelCore/GeoModelKernel/src/RCBase.cxx
@@ -1,5 +1,5 @@
/*
- Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+ Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
#include "GeoModelKernel/RCBase.h"
@@ -21,10 +21,7 @@ void RCBase::ref () const
void RCBase::unref () const
{
- if (m_count.load()>0) {
- m_count--;
- if (m_count.load()==0) delete this;
- }
+ if (--m_count == 0) delete this;
}
unsigned int RCBase::refCount () const
--
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