[Opalvoip-svn] SF.net SVN: opalvoip:[21271] ptlib/trunk/src/ptlib/unix/tlibthrd.cxx

[<hfr...@us...>]

Revision: 21271
          http://opalvoip.svn.sourceforge.net/opalvoip/?rev=21271&view=rev
Author:   hfriederich
Date:     2008-10-08 16:53:38 +0000 (Wed, 08 Oct 2008)

Log Message:
-----------
Fix deadlock within PTRACE()

Modified Paths:
--------------
    ptlib/trunk/src/ptlib/unix/tlibthrd.cxx

Modified: ptlib/trunk/src/ptlib/unix/tlibthrd.cxx
===================================================================
--- ptlib/trunk/src/ptlib/unix/tlibthrd.cxx	2008-10-08 05:37:41 UTC (rev 21270)
+++ ptlib/trunk/src/ptlib/unix/tlibthrd.cxx	2008-10-08 16:53:38 UTC (rev 21271)
@@ -826,6 +826,13 @@
   PThread * thread = (PThread *)arg;
   PProcess & process = PProcess::Current();
   process.OnThreadEnded(*thread);
+  
+  // Calls to PTRACE() MUST be made with activeThreadMutex unlocked, or deadlocks may occur.
+  // (PTRACE() itself calls PThread::Current()). Also, PTRACE must be done BEFORE removing the
+  // thread from the activeThreads dictionary, or PTrace::Current() will create a new 
+  // PExternalThread instance, causing the very same deadlock
+  PTRACE(5, "PWLib\tEnded thread " << thread << ' ' << thread->GetThreadName());
+  
   process.activeThreadMutex.Wait();
 
   pthread_t id = thread->GetThreadId();
@@ -835,10 +842,8 @@
     process.activeThreadMutex.Signal();
     PTRACE(2, "PWLib\tAttempted to multiply end thread " << thread << " ThreadID=" << (void *)id);
     return;
-  }  
+  }
 
-  PTRACE(5, "PWLib\tEnded thread " << thread << ' ' << thread->GetThreadName());
-
   // remove this thread from the active thread list
   process.activeThreads.SetAt((unsigned)id, NULL);
 


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.