* dcrt0.cc (child_info_fork::alloc_stack_hard_way): Change sense of guard test.

Increase size of stack reserved and increase size before the current stack
pointer.  Use pointers when doing arithmetic.
(dll_crt0_1): Initialize exception handler when we notice we're the child of a
fork from non-main thread.
* fork.cc (frok::parent): Make argument volatile.
(frok::child): Ditto.
(lock_signals): New class.
(lock_pthread): Ditto.
(hold_everhthing): Ditto.
(frok::parent): Move atforkprepare and atforkparent to lock_pthread class.
(fork): Make ischild boolean.  Use hold_everything variable within limited
scope to set various mutexes in such a way as to avoid deadlocks.
* thread.h (pthread_mutex::tid): New variable, active when debugging for
tracking thread id of owner.
(pthread_mutex::set_owner): Set tid when debugging.
* thread.cc (pthread_mutex::pthread_mutex): Clear tid.
(pthread_mutex::_unlock): Ditto when unlocking.
(pthread_mutex::fixup_after_fork): Set tid to special value after forking since
owner is unknown.

1 files changed, 24 insertions, 9 deletions

diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index fc29fc19a..936d9a55c 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -1,9 +1,7 @@
 /* thread.cc: Locking and threading module functions
 
-   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007 Red Hat, Inc.
-
-   Originally written by Marco Fuykschot <marco@ddi.nl>
-   Substantialy enhanced by Robert Collins <rbtcollins@hotmail.com>
+   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+   2006, 2007 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -1599,7 +1597,11 @@ pthread_mutex::pthread_mutex (pthread_mutexattr *attr) :
   verifyable_object (PTHREAD_MUTEX_MAGIC),
   lock_counter (0),
   win32_obj_id (NULL), recursion_counter (0),
-  condwaits (0), owner (NULL), type (PTHREAD_MUTEX_ERRORCHECK),
+  condwaits (0), owner (NULL),
+#ifdef DEBUGGING
+  tid (0),
+#endif
+  type (PTHREAD_MUTEX_ERRORCHECK),
   pshared (PTHREAD_PROCESS_PRIVATE)
 {
   win32_obj_id = ::CreateSemaphore (&sec_none_nih, 0, LONG_MAX, NULL);
@@ -1680,6 +1682,9 @@ pthread_mutex::_unlock (pthread_t self)
   if (--recursion_counter == 0)
     {
       owner = NULL;
+#ifdef DEBUGGING
+      tid = 0;
+#endif
       if (InterlockedDecrement ((long *)&lock_counter))
 	// Another thread is waiting
 	::ReleaseSemaphore (win32_obj_id, 1, NULL);
@@ -1713,11 +1718,21 @@ pthread_mutex::_fixup_after_fork ()
     api_fatal ("pthread_mutex::_fixup_after_fork () doesn'tunderstand PROCESS_SHARED mutex's");
 
   if (owner == NULL)
-    /* mutex has no owner, reset to initial */
-    lock_counter = 0;
+    {
+      /* mutex has no owner, reset to initial */
+      lock_counter = 0;
+#ifdef DEBUGGING
+      tid = 0;
+#endif
+    }
   else if (lock_counter != 0)
-    /* All waiting threads are gone after a fork */
-    lock_counter = 1;
+    {
+      /* All waiting threads are gone after a fork */
+      lock_counter = 1;
+#ifdef DEBUGGING
+      tid = 0xffffffff;	/* Don't know the tid after a fork */
+#endif
+    }
 
   win32_obj_id = ::CreateSemaphore (&sec_none_nih, 0, LONG_MAX, NULL);
   if (!win32_obj_id)