Changeset 63948 in vbox

Timestamp:

Sep 22, 2016 1:22:47 PM (8 years ago)

Author:

vboxsync

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

110834

Message:

VBoxGuest: VGDrvCommonWaitDoWakeUps must be thread-safe.

File:

• trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest.cpp (modified) (3 diffs)

trunk/src/VBox/Additions/common/VBoxGuest/VBoxGuest.cpp

@@ -1464 +1464 @@
  * All entries in the wake-up list gets signalled and moved to the woken-up
  * list.
+ * At least on Windows this function can be invoked concurrently from
+ * different VCPUs. So, be thread-safe.
  *
  * @param   pDevExt         The device extension.
@@ -1478 +1480 @@
             if (!pWait)
                 break;
+            /* Prevent other threads from accessing pWait when spinlock is released. */
+            RTListNodeRemove(&pWait->ListNode);
+
             pWait->fPendingWakeUp = true;
             RTSpinlockRelease(pDevExt->EventSpinlock);
@@ -1485 +1490 @@
 
             RTSpinlockAcquire(pDevExt->EventSpinlock);
+            Assert(pWait->ListNode.pNext == NULL && pWait->ListNode.pPrev == NULL);
+            RTListAppend(&pDevExt->WokenUpList, &pWait->ListNode);
             pWait->fPendingWakeUp = false;
-            if (!pWait->fFreeMe)
-            {
-                RTListNodeRemove(&pWait->ListNode);
-                RTListAppend(&pDevExt->WokenUpList, &pWait->ListNode);
-            }
+            if (RT_LIKELY(!pWait->fFreeMe))
+            { /* likely */ }
             else
             {