Changeset 27774 in vbox

Timestamp:

Mar 29, 2010 10:44:37 AM (15 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

59420

Message:

Main: fix locking order violation in Medium::CloneTo()

File:

• trunk/src/VBox/Main/MediumImpl.cpp (modified) (4 diffs)

trunk/src/VBox/Main/MediumImpl.cpp

@@ -2431 +2431 @@
         parent = static_cast<Medium*>(aParent);
 
-    AutoMultiWriteLock3 alock(this, target, parent COMMA_LOCKVAL_SRC_POS);
-
     ComObjPtr<Progress> progress;
     HRESULT rc = S_OK;
@@ -2438 +2436 @@
     try
     {
+        // locking: we need the tree lock first because we access parent pointers
+        AutoReadLock treeLock(m->pVirtualBox->getMediaTreeLockHandle() COMMA_LOCKVAL_SRC_POS);
+        // and we need to write-lock the images involved
+        AutoMultiWriteLock3 alock(this, target, parent COMMA_LOCKVAL_SRC_POS);
+
         if (    target->m->state != MediumState_NotCreated
             &&  target->m->state != MediumState_Created)
@@ -2449 +2452 @@
         std::auto_ptr <ImageChain> srcChain(new ImageChain());
 
-        /* we walk the source tree */
-        AutoReadLock treeLock(m->pVirtualBox->getMediaTreeLockHandle() COMMA_LOCKVAL_SRC_POS);
         for (Medium *hd = this;
              hd;
@@ -2521 +2522 @@
 
     if (SUCCEEDED(rc))
-    {
         /* return progress to the caller */
         progress.queryInterfaceTo(aProgress);
-    }
 
     return rc;