Changeset 98847 in vbox

Timestamp:

Mar 6, 2023 10:28:59 PM (21 months ago)

Author:

vboxsync

Message:

Main/Medium+VirtualBox: If two Machine instances of the same VM are
being torn down at the same time they can wrestle over the media tree
lock between Medium::i_close() and VirtualBox::i_unregisterMachineMedia()
and end up closing the same medium twice. Medium::i_close() drops the
media tree lock before calling Medium::uninit() and during this window
i_unregisterMachineMedia() can grab the lock and call i_close() for all
of the attached media including the medium in the process of being
closed. The fix checks inside i_close() whether the current medium is
already in the process of being closed and returns an error in such
cases. bugref:6447

Location:

trunk/src/VBox/Main/src-server

Files:

• MediumImpl.cpp (modified) (1 diff)
• VirtualBoxImpl.cpp (modified) (1 diff)

trunk/src/VBox/Main/src-server/MediumImpl.cpp

@@ -5673 +5673 @@
             return i_setStateError();
     }
+
+    if (m->fClosing)
+        return setError(VBOX_E_OBJECT_IN_USE,
+                        tr("Medium '%s' cannot be closed because it is already in the process of being closed", ""),
+                        m->strLocationFull.c_str());
 
     if (m->backRefs.size() != 0)

trunk/src/VBox/Main/src-server/VirtualBoxImpl.cpp

@@ -5348 +5348 @@
         Log(("Closing medium %RTuuid\n", pMedium->i_getId().raw()));
         AutoCaller mac(pMedium);
-        pMedium->i_close(mac);
+        HRESULT hrc = pMedium->i_close(mac);
+        if (FAILED(hrc))
+            return hrc;
     }