Make OleEmbeddedObject::GetRidOfComponent safer when releasing lock

Thanks Michael Stahl for the useful advise - see
https://gerrit.libreoffice.org/c/core/+/171996/comment/4dc20148_5ec861ad/

Change-Id: I16e1876a81a52f291ede49572f012c15d4cd9a6d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/172233
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/embeddedobj/source/msole/olemisc.cxx b/embeddedobj/source/msole/olemisc.cxx
index 13fc558a529e..582ae49de56f 100644
--- a/embeddedobj/source/msole/olemisc.cxx
+++ b/embeddedobj/source/msole/olemisc.cxx
@@ -230,23 +230,26 @@ void OleEmbeddedObject::GetRidOfComponent(osl::ResettableMutexGuard* guard)
             SaveObject_Impl();
 
         m_pOleComponent->removeCloseListener( m_xClosePreventer );
+        // When releasing the guard below, avoid a case when two threads are doing the same;
+        // store the reference on stack and clear m_pOleComponent in advance
+        rtl::Reference<OleComponent> pOleComponent(std::move(m_pOleComponent));
         try
         {
             std::optional<osl::ResettableMutexGuardScopedReleaser> oReleaser;
             if (guard)
                 oReleaser.emplace(*guard);
-            m_pOleComponent->close( false );
+            pOleComponent->close(false);
         }
         catch( const uno::Exception& )
         {
+            m_pOleComponent = std::move(pOleComponent);
             // TODO: there should be a special listener to wait for component closing
             //       and to notify object, may be object itself can be such a listener
             m_pOleComponent->addCloseListener( m_xClosePreventer );
             throw;
         }
 
-        m_pOleComponent->disconnectEmbeddedObject();
-        m_pOleComponent.clear();
+        pOleComponent->disconnectEmbeddedObject();
     }
 #else
     (void)guard;