* pinfo.cc (proc_waiter): Zero wait_thread in child to avoid races with process

termination.
* cygthread.cc (cygthread::terminate): Clumsily detect when h has gone away and
attempt no further action.

3 files changed, 24 insertions, 1 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 88148bf..364f8c3 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,5 +1,12 @@
 2004-12-22  Christopher Faylor  <cgf@timesys.com>
 
+	* pinfo.cc (proc_waiter): Zero wait_thread in child to avoid races with
+	process termination.
+	* cygthread.cc (cygthread::terminate): Clumsily detect when h has gone away
+	and attempt no further action.
+
+2004-12-22  Christopher Faylor  <cgf@timesys.com>
+
 	* cygthread.h (cygthread::release): Just declare here.
 	* cygthread.cc (cygthread::release): Define here.  Use
 	InterlockedExchange to set inuse or suffer potential races.
diff --git a/winsup/cygwin/cygthread.cc b/winsup/cygwin/cygthread.cc
index d20bf68..80fc5e0 100644
--- a/winsup/cygwin/cygthread.cc
+++ b/winsup/cygwin/cygthread.cc
@@ -226,18 +226,33 @@ cygthread::release ()
 void
 cygthread::terminate_thread ()
 {
+  /* FIXME: The if (!h) stuff below should be handled better.  The
+     problem is that terminate_thread could be called while a thread
+     is terminating and either the thread could be handling its own
+     release or, if this is being called during exit, some other
+     thread may be attempting to free up this resource.  In the former
+     case, setting some kind of "I deal with my own exit" type of
+     flag may be the way to handle this. */
   if (!is_freerange)
     {
       ResetEvent (*this);
       ResetEvent (thread_sync);
     }
+  if (!h)
+    return;
   (void) TerminateThread (h, 0);
   (void) WaitForSingleObject (h, INFINITE);
+  if (!h)
+    return;
+
   CloseHandle (h);
 
-  while (!stack_ptr)
+  while (h && !stack_ptr)
     low_priority_sleep (0);
 
+  if (!h)
+    return;
+
   MEMORY_BASIC_INFORMATION m;
   memset (&m, 0, sizeof (m));
   (void) VirtualQuery (stack_ptr, &m, sizeof m);
diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index a26336c..508ed5c 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -763,6 +763,7 @@ proc_waiter (void *arg)
     }
 
   sigproc_printf ("exiting wait thread for pid %d", pid);
+  vchild.wait_thread = NULL;
   _my_tls._ctinfo->release ();	/* return the cygthread to the cygthread pool */
   return 0;
 }