Changeset 8756 in vbox for trunk/src

Timestamp:

May 11, 2008 2:43:49 PM (17 years ago)

Author:

vboxsync

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

30736

Message:

Main/AutoLock: Fixed: Two or more write locks could be acquired simultaneously on different threads if a read lock was requested while one or more write locks were pending.

File:

• trunk/src/VBox/Main/AutoLock.cpp (modified) (1 diff)

trunk/src/VBox/Main/AutoLock.cpp

@@ -373 +373 @@
 
             /* write locks are top priority, so let them go if they are
-             * pending */
-            if (mWriteLockPending != 0)
+             * pending and we're the only reader so far */
+            if (mWriteLockPending != 0 && isFirstReadLock)
             {
                 isWriteLock = true;
-                /* the first postponed reader kicks pending writers */
-                if (isFirstReadLock)
-                    RTSemEventSignal (mGoWriteSem);
+                /* note that we must not signal mGoWriteSem here because it
+                 * has been already signaled by unlockWrite() or by
+                 * unlockRead() */
             }
         }