Avoid race between {,__de}allocate_stack and __reclaim_stacks during fork

5 files changed, 35 insertions, 8 deletions

diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 15c785bf4e..ae48299a41 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,12 @@
+2011-09-15  Andreas Schwab  <schwab@redhat.com>
+
+	* sysdeps/pthread/list.h: Define only list_t if __need_list_t is
+	defined.
+	(list_add): Add atomic_write_barrier.
+	* descr.h: Define __need_list_t before including <list.h>.
+	* nptl-init.c: Include <list.h>
+	* allocatestack.c: Likewise.
+
 2011-09-11  Ulrich Drepper  <drepper@gmail.com>
 
 	* sysdeps/i386/tls.h: Remove HAVE_TLS_SUPPORT test.
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 23d2ce559c..36b4aa16fd 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -28,6 +28,7 @@
 #include <dl-sysdep.h>
 #include <dl-tls.h>
 #include <tls.h>
+#include <list.h>
 #include <lowlevellock.h>
 #include <kernel-features.h>
 
diff --git a/nptl/descr.h b/nptl/descr.h
index 9c366e7400..e57e29e311 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -26,6 +26,7 @@
 #include <stdbool.h>
 #include <sys/types.h>
 #include <hp-timing.h>
+#define __need_list_t
 #include <list.h>
 #include <lowlevellock.h>
 #include <pthreaddef.h>
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 33492c1602..db45cab230 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -29,6 +29,7 @@
 #include <atomic.h>
 #include <ldsodefs.h>
 #include <tls.h>
+#include <list.h>
 #include <fork.h>
 #include <version.h>
 #include <shlib-compat.h>
diff --git a/nptl/sysdeps/pthread/list.h b/nptl/sysdeps/pthread/list.h
index 6ddccb9fb9..cfc4abad3c 100644
--- a/nptl/sysdeps/pthread/list.h
+++ b/nptl/sysdeps/pthread/list.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2009, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -18,27 +18,39 @@
    02111-1307 USA.  */
 
 #ifndef _LIST_H
-#define _LIST_H	1
+
+#ifndef __need_list_t
+# define _LIST_H	1
+#endif
 
 /* The definitions of this file are adopted from those which can be
    found in the Linux kernel headers to enable people familiar with
    the latter find their way in these sources as well.  */
 
 
+#if defined __need_list_t || defined _LIST_H
+# ifndef __list_t_defined
+#  define __list_t_defined
 /* Basic type for the double-link list.  */
 typedef struct list_head
 {
   struct list_head *next;
   struct list_head *prev;
 } list_t;
+# endif
+# undef __need_list_t
+#endif
+
+#ifdef _LIST_H
 
+# include <atomic.h>
 
 /* Define a variable with the head and tail of the list.  */
-#define LIST_HEAD(name) \
+# define LIST_HEAD(name) \
   list_t name = { &(name), &(name) }
 
 /* Initialize a new list head.  */
-#define INIT_LIST_HEAD(ptr) \
+# define INIT_LIST_HEAD(ptr) \
   (ptr)->next = (ptr)->prev = (ptr)
 
 
@@ -49,6 +61,7 @@ list_add (list_t *newp, list_t *head)
   newp->next = head->next;
   newp->prev = head;
   head->next->prev = newp;
+  atomic_write_barrier ();
   head->next = newp;
 }
 
@@ -78,26 +91,28 @@ list_splice (list_t *add, list_t *head)
 
 
 /* Get typed element from list at a given position.  */
-#define list_entry(ptr, type, member) \
+# define list_entry(ptr, type, member) \
   ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
 
 
 
 /* Iterate forward over the elements of the list.  */
-#define list_for_each(pos, head) \
+# define list_for_each(pos, head) \
   for (pos = (head)->next; pos != (head); pos = pos->next)
 
 
 /* Iterate forward over the elements of the list.  */
-#define list_for_each_prev(pos, head) \
+# define list_for_each_prev(pos, head) \
   for (pos = (head)->prev; pos != (head); pos = pos->prev)
 
 
 /* Iterate backwards over the elements list.  The list elements can be
    removed from the list while doing this.  */
-#define list_for_each_prev_safe(pos, p, head) \
+# define list_for_each_prev_safe(pos, p, head) \
   for (pos = (head)->prev, p = pos->prev; \
        pos != (head); \
        pos = p, p = pos->prev)
 
+#endif /* _LIST_H */
+
 #endif	/* list.h */